TV RGB mod thread

[Anonygoose]

Could you confirm a couple of things please?

1- Where do I add the coupler caps? I also only have regular polarized electrolytic in hand at the moment. I'm using a Sunthar board.

2- Do I inject RGB at IC206 pins? Or somewhere in between where it says OSD RGB? The caps maybe opposite side of the pins?

3- Do I keep the switch wired directly to the jungle blanking?

1- The caps would be placed right where you are tapping at the end of your RGB lines. Notice how the original schematic has an inline cap right at the inputs of R2 B2 G2 of IC206. This usually means there is DC voltage on those OSD RGB lines for biasing and those coupling capacitors will isolate it from IC206. But to this properly you could also get some measurements so that you know exactly what is going on. Measure that cap on both sides, the OSD and the switch pins side and make notes. You will probably see something like 2v DC on the OSD side, and 0v on the switch side. Then you can measure your external RGB lines coming in and you probably will see around 0v DC or just slights amount of it if there is some offset. If the offset on external RGB is low enough then you might get away with tapping in on the switch IC206 side of that cap or directly to the pins. But generally to be on the safe side you would add your own coupling caps so that any DC offset from the external RGB side is isolated from the switch. But for a quick test to see if this part of the circuit is working you might be able to get away with direct to the pin. A polarized will probably work fine but sometimes non polarized is easier. You want the positive side of the cap facing whichever side has the higher DC offset. So if you measure 2v DC on the OSD RGB lines and you are tapping there, the positive will most likely be towards the OSD lines because that should be much higher than the external RGB lines. If you tap on IC206 pin side then it is more likely that the external RGB is going to have the higher DC voltage and the most variation of offset so you will have the positive side on the external RGB lines. A non polarized here is useful because it will always cover both ways. A 1uF cap will probably cover it just fine, but you might be able to get away with a 0.1uF as well. I wouldn't go higher than 10uF, but you are probably fine with that for testing if that is what you have.

2- Sort of answered above. Not sure where the caps would be, but it is quit possible they are ceramic and SMD.

3- You will actually want to tap your blanking with that switch as well. You will see just below IC206 there is a OSD-F/B line. This is where you will want to tap because the F/B will cause that switch to engage inputs 2 / OSD RGB lines, then IC206 has an output to trigger the jungle F/B as well. Keep in mind that that F/B line goes all the way back to the OSD chip and connects to pin 27 so you will have interaction with that part of the circuit, most importantly R928 1.8k pull down resistor. I think you were tuning your voltage divider with a 1k divider before, so your blanking signal is now going to be 5v 4.7k / 1.8k. IC206 might require slightly higher voltage to trigger so this might be fine to start with, but you might need to adjust this a little. You can probably start with that though. The OSD F/B is showing what seems to be a 5v 120 / 1.8k which means it is only slightly dropping the voltage which means you might have to match that. But this is assuming that it is starting with 5v. Ultimately you should measure that OSD pin when the OSD is turned on just to make sure, then you can measure the F/B at the IC206 F/B pins after that divider to see what that chip is expecting. Or look at the datasheet for TEA5114A and see what it wants for triggering the switch.

Hopefully that clarifies the goal points.

Hello!

Been procrastinating on this for a while but I finally have a good update, although with some weird results. I have RGB finally following the steps you outlined above which is great. Thank you very much for the detailed explanations.

Couple of issues:

1- RGB would only blank with 5V straight. Putting a 1k resistor in series for safety between the switch and the 5v source wouldn't blank. Is this safe?

2- The picture is very dim compared to composite. So to fix this I need to lower the values of the RGB inline resistors on the mux board, correct? I used 800ohm resistors. Thinking to drop to 680ohm since it's super dim.

[Delphius]

Could you confirm a couple of things please?

1- Where do I add the coupler caps? I also only have regular polarized electrolytic in hand at the moment. I'm using a Sunthar board.

2- Do I inject RGB at IC206 pins? Or somewhere in between where it says OSD RGB? The caps maybe opposite side of the pins?

3- Do I keep the switch wired directly to the jungle blanking?

1- The caps would be placed right where you are tapping at the end of your RGB lines. Notice how the original schematic has an inline cap right at the inputs of R2 B2 G2 of IC206. This usually means there is DC voltage on those OSD RGB lines for biasing and those coupling capacitors will isolate it from IC206. But to this properly you could also get some measurements so that you know exactly what is going on. Measure that cap on both sides, the OSD and the switch pins side and make notes. You will probably see something like 2v DC on the OSD side, and 0v on the switch side. Then you can measure your external RGB lines coming in and you probably will see around 0v DC or just slights amount of it if there is some offset. If the offset on external RGB is low enough then you might get away with tapping in on the switch IC206 side of that cap or directly to the pins. But generally to be on the safe side you would add your own coupling caps so that any DC offset from the external RGB side is isolated from the switch. But for a quick test to see if this part of the circuit is working you might be able to get away with direct to the pin. A polarized will probably work fine but sometimes non polarized is easier. You want the positive side of the cap facing whichever side has the higher DC offset. So if you measure 2v DC on the OSD RGB lines and you are tapping there, the positive will most likely be towards the OSD lines because that should be much higher than the external RGB lines. If you tap on IC206 pin side then it is more likely that the external RGB is going to have the higher DC voltage and the most variation of offset so you will have the positive side on the external RGB lines. A non polarized here is useful because it will always cover both ways. A 1uF cap will probably cover it just fine, but you might be able to get away with a 0.1uF as well. I wouldn't go higher than 10uF, but you are probably fine with that for testing if that is what you have.

2- Sort of answered above. Not sure where the caps would be, but it is quit possible they are ceramic and SMD.

3- You will actually want to tap your blanking with that switch as well. You will see just below IC206 there is a OSD-F/B line. This is where you will want to tap because the F/B will cause that switch to engage inputs 2 / OSD RGB lines, then IC206 has an output to trigger the jungle F/B as well. Keep in mind that that F/B line goes all the way back to the OSD chip and connects to pin 27 so you will have interaction with that part of the circuit, most importantly R928 1.8k pull down resistor. I think you were tuning your voltage divider with a 1k divider before, so your blanking signal is now going to be 5v 4.7k / 1.8k. IC206 might require slightly higher voltage to trigger so this might be fine to start with, but you might need to adjust this a little. You can probably start with that though. The OSD F/B is showing what seems to be a 5v 120 / 1.8k which means it is only slightly dropping the voltage which means you might have to match that. But this is assuming that it is starting with 5v. Ultimately you should measure that OSD pin when the OSD is turned on just to make sure, then you can measure the F/B at the IC206 F/B pins after that divider to see what that chip is expecting. Or look at the datasheet for TEA5114A and see what it wants for triggering the switch.

Hopefully that clarifies the goal points.

Hello!

Been procrastinating on this for a while but I finally have a good update, although with some weird results. I have RGB finally following the steps you outlined above which is great. Thank you very much for the detailed explanations.

Couple of issues:

1- RGB would only blank with 5V straight. Putting a 1k resistor in series for safety between the switch and the 5v source wouldn't blank. Is this safe?

2- The picture is very dim compared to composite. So to fix this I need to lower the values of the RGB inline resistors on the mux board, correct? I used 800ohm resistors. Thinking to drop to 680ohm since it's super dim.

Great! Glad you are making some progress with this.

I can't think of any strong reasons why 5v direct to FB would be an issue if it is working, but I would be curious what the measurement is there when you do. It must be getting pulled down somewhere and stronger than expected so you probably won't see 5v there. But you could try something as low as 100R series if you want to be a little more on the safe side. But can you remind me if you are also using a diode on your added FB line? That might be more important for safety if you are bringing FB from external. It also will create a slight voltage drop.

You should be on the right track with changing the series resistors to change the brightness. If you aren't muxing with the OSD then it should be pretty straight forward. If you are muxing then it might take tweaking on each source or even the pull down attached them.

It has been a minute since I looked at this schematic as well so I would have to look it over more closely again to know for sure. But changing the series resistors like you mentioned should be all that you need.

[Anonygoose]

1- The caps would be placed right where you are tapping at the end of your RGB lines. Notice how the original schematic has an inline cap right at the inputs of R2 B2 G2 of IC206. This usually means there is DC voltage on those OSD RGB lines for biasing and those coupling capacitors will isolate it from IC206. But to this properly you could also get some measurements so that you know exactly what is going on. Measure that cap on both sides, the OSD and the switch pins side and make notes. You will probably see something like 2v DC on the OSD side, and 0v on the switch side. Then you can measure your external RGB lines coming in and you probably will see around 0v DC or just slights amount of it if there is some offset. If the offset on external RGB is low enough then you might get away with tapping in on the switch IC206 side of that cap or directly to the pins. But generally to be on the safe side you would add your own coupling caps so that any DC offset from the external RGB side is isolated from the switch. But for a quick test to see if this part of the circuit is working you might be able to get away with direct to the pin. A polarized will probably work fine but sometimes non polarized is easier. You want the positive side of the cap facing whichever side has the higher DC offset. So if you measure 2v DC on the OSD RGB lines and you are tapping there, the positive will most likely be towards the OSD lines because that should be much higher than the external RGB lines. If you tap on IC206 pin side then it is more likely that the external RGB is going to have the higher DC voltage and the most variation of offset so you will have the positive side on the external RGB lines. A non polarized here is useful because it will always cover both ways. A 1uF cap will probably cover it just fine, but you might be able to get away with a 0.1uF as well. I wouldn't go higher than 10uF, but you are probably fine with that for testing if that is what you have.

2- Sort of answered above. Not sure where the caps would be, but it is quit possible they are ceramic and SMD.

3- You will actually want to tap your blanking with that switch as well. You will see just below IC206 there is a OSD-F/B line. This is where you will want to tap because the F/B will cause that switch to engage inputs 2 / OSD RGB lines, then IC206 has an output to trigger the jungle F/B as well. Keep in mind that that F/B line goes all the way back to the OSD chip and connects to pin 27 so you will have interaction with that part of the circuit, most importantly R928 1.8k pull down resistor. I think you were tuning your voltage divider with a 1k divider before, so your blanking signal is now going to be 5v 4.7k / 1.8k. IC206 might require slightly higher voltage to trigger so this might be fine to start with, but you might need to adjust this a little. You can probably start with that though. The OSD F/B is showing what seems to be a 5v 120 / 1.8k which means it is only slightly dropping the voltage which means you might have to match that. But this is assuming that it is starting with 5v. Ultimately you should measure that OSD pin when the OSD is turned on just to make sure, then you can measure the F/B at the IC206 F/B pins after that divider to see what that chip is expecting. Or look at the datasheet for TEA5114A and see what it wants for triggering the switch.

Hopefully that clarifies the goal points.

Hello!

Been procrastinating on this for a while but I finally have a good update, although with some weird results. I have RGB finally following the steps you outlined above which is great. Thank you very much for the detailed explanations.

Couple of issues:

1- RGB would only blank with 5V straight. Putting a 1k resistor in series for safety between the switch and the 5v source wouldn't blank. Is this safe?

2- The picture is very dim compared to composite. So to fix this I need to lower the values of the RGB inline resistors on the mux board, correct? I used 800ohm resistors. Thinking to drop to 680ohm since it's super dim.

Great! Glad you are making some progress with this.

I can't think of any strong reasons why 5v direct to FB would be an issue if it is working, but I would be curious what the measurement is there when you do. It must be getting pulled down somewhere and stronger than expected so you probably won't see 5v there. But you could try something as low as 100R series if you want to be a little more on the safe side. But can you remind me if you are also using a diode on your added FB line? That might be more important for safety if you are bringing FB from external. It also will create a slight voltage drop.

You should be on the right track with changing the series resistors to change the brightness. If you aren't muxing with the OSD then it should be pretty straight forward. If you are muxing then it might take tweaking on each source or even the pull down attached them.

It has been a minute since I looked at this schematic as well so I would have to look it over more closely again to know for sure. But changing the series resistors like you mentioned should be all that you need.

I have a diode on the mux board, yes. 1N4148.

I just reduced to 680R but still pretty dim. I'm not sure I'm seeing any difference actually from 800R.

Could the coupling capacitors I installed at the switch cause this? I used polarized 1uf caps. Maybe I installed them backwards. I have the negative legs attached to the pins on the switch IC206 and the positive to the RGB coming from the mux board

Edit: Getting 4.8V approximately at the blanking pins.

Edit 2: 3.6V at the RGB pins (negative legs) and nothing at all positive legs

[Delphius]

I have a diode on the mux board, yes. 1N4148.

I just reduced to 680R but still pretty dim. I'm not sure I'm seeing any difference actually from 800R.

Could the coupling capacitors I installed at the switch cause this? I used polarized 1uf caps. Maybe I installed them backwards. I have the negative legs attached to the pins on the switch IC206 and the positive to the RGB coming from the mux board

Edit: Getting 4.8V approximately at the blanking pins.

Edit 2: 3.6V at the RGB pins (negative legs) and nothing at all positive legs

Ok so I am looking at the schematic again for a reminder of what is going on. So I think the main thing to keep in mind is that you are now muxing in the OSD network so everything you are doing interacts with R924 R926 R928 series resistors, and the R923 R925 R927 pull down resistors next to the outputs of the OSD chip (maybe not physically next to it). Since you are now adding the 75R termination resistor on your mux board, it is probably pulling down harder than it was. You can keep trying to get brightness by continuing to lower the resistors even further from 680R like you have been trying, but this might be where the RGB mux calculator is going to come in to play. You might need to remove R923 R925 R927 and follow the similar pattern and calculation in common muxing mods like shown here.

https://sunthar.com/rgb-mux-calculator

Adjust your resistors according to this to find a decent reference spot.

Or a good way to give it a quick test might be to temporarily remove the OSD from the circuit entirely if you have easy access to remove C266 C268 and C270 next to IC206. If you remove those from the equation, your current external RGB configuration might be a little more accurate. It should at least show you if the interaction with the OSD network is causing your shift or not, but you will still need to adjust once it is added back in if you want OSD.

I don't think that the polarity of the caps are making a difference on the brightness, but it is still important to have these in the correct polarity or get a non polarized cap for this purpose. But I would think that it is more likely that you have positive legs of the caps towards the IC206, but you might not know for sure without measuring it. Without your external RGB connected measure the voltage on that line connected to the OSD. As an example if you are seeing a steady 2v DC voltage on that line, then measuring your external RGB line you see 0v or even 1v DC voltage (probably should be 0v but just for demonstration purposes), then you point the polarity towards the one with the highest DC voltage. Most likely the OSD line is and should be the highest voltage. External sources shouldn't really have any DC voltage, but I suppose there are some situations where there might be an offset, like a stock SNES without coupling capacitors in the cable.

edit: Just noticed your Edit 2: about the 3.6V at RGB pins. This would indicate that your caps are backwards.

[Anonygoose]

Oops. Luckily I didn't blow the TV up. I'll reverse the caps. Alright, let me see what happens with your suggestions above. I'll post an update. Thanks again, you've been extremely helpful.

[Anonygoose]

I have a diode on the mux board, yes. 1N4148.

I just reduced to 680R but still pretty dim. I'm not sure I'm seeing any difference actually from 800R.

Could the coupling capacitors I installed at the switch cause this? I used polarized 1uf caps. Maybe I installed them backwards. I have the negative legs attached to the pins on the switch IC206 and the positive to the RGB coming from the mux board

Edit: Getting 4.8V approximately at the blanking pins.

Edit 2: 3.6V at the RGB pins (negative legs) and nothing at all positive legs

Ok so I am looking at the schematic again for a reminder of what is going on. So I think the main thing to keep in mind is that you are now muxing in the OSD network so everything you are doing interacts with R924 R926 R928 series resistors, and the R923 R925 R927 pull down resistors next to the outputs of the OSD chip (maybe not physically next to it). Since you are now adding the 75R termination resistor on your mux board, it is probably pulling down harder than it was. You can keep trying to get brightness by continuing to lower the resistors even further from 680R like you have been trying, but this might be where the RGB mux calculator is going to come in to play. You might need to remove R923 R925 R927 and follow the similar pattern and calculation in common muxing mods like shown here.

https://sunthar.com/rgb-mux-calculator

Adjust your resistors according to this to find a decent reference spot.

Or a good way to give it a quick test might be to temporarily remove the OSD from the circuit entirely if you have easy access to remove C266 C268 and C270 next to IC206. If you remove those from the equation, your current external RGB configuration might be a little more accurate. It should at least show you if the interaction with the OSD network is causing your shift or not, but you will still need to adjust once it is added back in if you want OSD.

I don't think that the polarity of the caps are making a difference on the brightness, but it is still important to have these in the correct polarity or get a non polarized cap for this purpose. But I would think that it is more likely that you have positive legs of the caps towards the IC206, but you might not know for sure without measuring it. Without your external RGB connected measure the voltage on that line connected to the OSD. As an example if you are seeing a steady 2v DC voltage on that line, then measuring your external RGB line you see 0v or even 1v DC voltage (probably should be 0v but just for demonstration purposes), then you point the polarity towards the one with the highest DC voltage. Most likely the OSD line is and should be the highest voltage. External sources shouldn't really have any DC voltage, but I suppose there are some situations where there might be an offset, like a stock SNES without coupling capacitors in the cable.

edit: Just noticed your Edit 2: about the 3.6V at RGB pins. This would indicate that your caps are backwards.

I dropped to 330R but still pretty dim. I removed the grounding OSD resistors previously when I first did the mod, so that's not the problem. Reversed the coupling caps as well just now.

I'm not sure how Sunthar's calculator works, I input all the values but it always says to use 827R for the external RGB resistors. Anyway, I used the list on his website to check for the pre calculated values and it says they need to be 330R.

My next assumption would be to drop the terminating resistors to 50R. Is that OK?

[Delphius]

I have a diode on the mux board, yes. 1N4148.

I just reduced to 680R but still pretty dim. I'm not sure I'm seeing any difference actually from 800R.

Could the coupling capacitors I installed at the switch cause this? I used polarized 1uf caps. Maybe I installed them backwards. I have the negative legs attached to the pins on the switch IC206 and the positive to the RGB coming from the mux board

Edit: Getting 4.8V approximately at the blanking pins.

Edit 2: 3.6V at the RGB pins (negative legs) and nothing at all positive legs

Ok so I am looking at the schematic again for a reminder of what is going on. So I think the main thing to keep in mind is that you are now muxing in the OSD network so everything you are doing interacts with R924 R926 R928 series resistors, and the R923 R925 R927 pull down resistors next to the outputs of the OSD chip (maybe not physically next to it). Since you are now adding the 75R termination resistor on your mux board, it is probably pulling down harder than it was. You can keep trying to get brightness by continuing to lower the resistors even further from 680R like you have been trying, but this might be where the RGB mux calculator is going to come in to play. You might need to remove R923 R925 R927 and follow the similar pattern and calculation in common muxing mods like shown here.

https://sunthar.com/rgb-mux-calculator

Adjust your resistors according to this to find a decent reference spot.

Or a good way to give it a quick test might be to temporarily remove the OSD from the circuit entirely if you have easy access to remove C266 C268 and C270 next to IC206. If you remove those from the equation, your current external RGB configuration might be a little more accurate. It should at least show you if the interaction with the OSD network is causing your shift or not, but you will still need to adjust once it is added back in if you want OSD.

I don't think that the polarity of the caps are making a difference on the brightness, but it is still important to have these in the correct polarity or get a non polarized cap for this purpose. But I would think that it is more likely that you have positive legs of the caps towards the IC206, but you might not know for sure without measuring it. Without your external RGB connected measure the voltage on that line connected to the OSD. As an example if you are seeing a steady 2v DC voltage on that line, then measuring your external RGB line you see 0v or even 1v DC voltage (probably should be 0v but just for demonstration purposes), then you point the polarity towards the one with the highest DC voltage. Most likely the OSD line is and should be the highest voltage. External sources shouldn't really have any DC voltage, but I suppose there are some situations where there might be an offset, like a stock SNES without coupling capacitors in the cable.

edit: Just noticed your Edit 2: about the 3.6V at RGB pins. This would indicate that your caps are backwards.

I dropped to 330R but still pretty dim. I removed the grounding OSD resistors previously when I first did the mod, so that's not the problem. Reversed the coupling caps as well just now.

I'm not sure how Sunthar's calculator works, I input all the values but it always says to use 827R for the external RGB resistors. Anyway, I used the list on his website to check for the pre calculated values and it says they need to be 330R.

My next assumption would be to drop the terminating resistors to 50R. Is that OK?

Do you have a oscilloscope you can use to measure the ptp voltage coming from the external RGB? The right way to go would be to move the terminating resistor higher in value for more brightness. Try something like 150R and see if that changes much. With the scope you an also measure what the ptp voltage is from the OSD to understand what we are trying to match. It should usually be 0.7v ptp or I guess 0.5v ptp for some TVs. I will try to find some data on the jungle chip to see if I can get some more information.

[Anonygoose]

Ok so I am looking at the schematic again for a reminder of what is going on. So I think the main thing to keep in mind is that you are now muxing in the OSD network so everything you are doing interacts with R924 R926 R928 series resistors, and the R923 R925 R927 pull down resistors next to the outputs of the OSD chip (maybe not physically next to it). Since you are now adding the 75R termination resistor on your mux board, it is probably pulling down harder than it was. You can keep trying to get brightness by continuing to lower the resistors even further from 680R like you have been trying, but this might be where the RGB mux calculator is going to come in to play. You might need to remove R923 R925 R927 and follow the similar pattern and calculation in common muxing mods like shown here.

https://sunthar.com/rgb-mux-calculator

Adjust your resistors according to this to find a decent reference spot.

Or a good way to give it a quick test might be to temporarily remove the OSD from the circuit entirely if you have easy access to remove C266 C268 and C270 next to IC206. If you remove those from the equation, your current external RGB configuration might be a little more accurate. It should at least show you if the interaction with the OSD network is causing your shift or not, but you will still need to adjust once it is added back in if you want OSD.

I don't think that the polarity of the caps are making a difference on the brightness, but it is still important to have these in the correct polarity or get a non polarized cap for this purpose. But I would think that it is more likely that you have positive legs of the caps towards the IC206, but you might not know for sure without measuring it. Without your external RGB connected measure the voltage on that line connected to the OSD. As an example if you are seeing a steady 2v DC voltage on that line, then measuring your external RGB line you see 0v or even 1v DC voltage (probably should be 0v but just for demonstration purposes), then you point the polarity towards the one with the highest DC voltage. Most likely the OSD line is and should be the highest voltage. External sources shouldn't really have any DC voltage, but I suppose there are some situations where there might be an offset, like a stock SNES without coupling capacitors in the cable.

edit: Just noticed your Edit 2: about the 3.6V at RGB pins. This would indicate that your caps are backwards.

I dropped to 330R but still pretty dim. I removed the grounding OSD resistors previously when I first did the mod, so that's not the problem. Reversed the coupling caps as well just now.

I'm not sure how Sunthar's calculator works, I input all the values but it always says to use 827R for the external RGB resistors. Anyway, I used the list on his website to check for the pre calculated values and it says they need to be 330R.

My next assumption would be to drop the terminating resistors to 50R. Is that OK?

Do you have a oscilloscope you can use to measure the ptp voltage coming from the external RGB? The right way to go would be to move the terminating resistor higher in value for more brightness. Try something like 150R and see if that changes much. With the scope you an also measure what the ptp voltage is from the OSD to understand what we are trying to match. It should usually be 0.7v ptp or I guess 0.5v ptp for some TVs. I will try to find some data on the jungle chip to see if I can get some more information.

150R did the job. Looks perfect. The OSD is faint though, but usable. This is a result of dropping the external RGB resistors to 330R?

Should I go through the trouble of scoping it or am I good to go? Picture looks perfect to me now.

Tube on this is ultra sharp. For 36 inch the geo and convergence is great.

[Delphius]

I dropped to 330R but still pretty dim. I removed the grounding OSD resistors previously when I first did the mod, so that's not the problem. Reversed the coupling caps as well just now.

I'm not sure how Sunthar's calculator works, I input all the values but it always says to use 827R for the external RGB resistors. Anyway, I used the list on his website to check for the pre calculated values and it says they need to be 330R.

My next assumption would be to drop the terminating resistors to 50R. Is that OK?

Do you have a oscilloscope you can use to measure the ptp voltage coming from the external RGB? The right way to go would be to move the terminating resistor higher in value for more brightness. Try something like 150R and see if that changes much. With the scope you an also measure what the ptp voltage is from the OSD to understand what we are trying to match. It should usually be 0.7v ptp or I guess 0.5v ptp for some TVs. I will try to find some data on the jungle chip to see if I can get some more information.

150R did the job. Looks perfect. The OSD is faint though, but usable. This is a result of dropping the external RGB resistors to 330R?

Should I go through the trouble of scoping it or am I good to go? Picture looks perfect to me now.

Tube on this is ultra sharp. For 36 inch the geo and convergence is great.

Awesome! Getting the balance correct with the OSD might be a little tricky, but might be worth it. You can try swapping out the series resistors a bit to see if that helps. If you have 240p test suite I would at least do some checking with some color bars to make sure you have the full range and even brightness. Using a scope will be more accurate, but the 240p test suite should help you get close, probably close enough.

Super Metroid is a good test game I like to use as well because it can show flaws in the darker colors if the blacks are crushed. You will lose a lot of details especially in the back grounds if anything is crushed.

[Anonygoose]

Do you have a oscilloscope you can use to measure the ptp voltage coming from the external RGB? The right way to go would be to move the terminating resistor higher in value for more brightness. Try something like 150R and see if that changes much. With the scope you an also measure what the ptp voltage is from the OSD to understand what we are trying to match. It should usually be 0.7v ptp or I guess 0.5v ptp for some TVs. I will try to find some data on the jungle chip to see if I can get some more information.

150R did the job. Looks perfect. The OSD is faint though, but usable. This is a result of dropping the external RGB resistors to 330R?

Should I go through the trouble of scoping it or am I good to go? Picture looks perfect to me now.

Tube on this is ultra sharp. For 36 inch the geo and convergence is great.

Awesome! Getting the balance correct with the OSD might be a little tricky, but might be worth it. You can try swapping out the series resistors a bit to see if that helps. If you have 240p test suite I would at least do some checking with some color bars to make sure you have the full range and even brightness. Using a scope will be more accurate, but the 240p test suite should help you get close, probably close enough.

Super Metroid is a good test game I like to use as well because it can show flaws in the darker colors if the blacks are crushed. You will lose a lot of details especially in the back grounds if anything is crushed.

Thanks so much again for all the help. It's been a long journey but totally worth it. I'll document the process in case anyone in the future needs it and post here.

Looks good in the test suite and will calibrate it with my colorimeter soon. I'll post results

[Delphius]

Thanks so much again for all the help. It's been a long journey but totally worth it. I'll document the process in case anyone in the future needs it and post here.

Looks good in the test suite and will calibrate it with my colorimeter soon. I'll post results

Happy to help, and I am glad it all worked out! Thank you for sharing your results, I am sure it will be helpful to anyone else looking to mod the same or similar TV. Keep us in touch!

[Delphius]

150R did the job. Looks perfect. The OSD is faint though, but usable. This is a result of dropping the external RGB resistors to 330R?

Should I go through the trouble of scoping it or am I good to go? Picture looks perfect to me now.

Tube on this is ultra sharp. For 36 inch the geo and convergence is great.

I had a thought about the OSD that you might want to give a try. If I remember correctly about how the muxing mod works, you are totally correct that dropping the resistors to 330R is probably affecting the brightness of the OSD. I think it controls the voltage divider on the OSD network. I don't think it is supposed to change much with the external RGB which is probably why changing those wasn't really helping the external RGB much. If you bump them to 820R you might be closer to where you want to be with the muxing. But it still might have a slight affect on external RGB, I am not certain.

[Anonygoose]

150R did the job. Looks perfect. The OSD is faint though, but usable. This is a result of dropping the external RGB resistors to 330R?

Should I go through the trouble of scoping it or am I good to go? Picture looks perfect to me now.

Tube on this is ultra sharp. For 36 inch the geo and convergence is great.

I had a thought about the OSD that you might want to give a try. If I remember correctly about how the muxing mod works, you are totally correct that dropping the resistors to 330R is probably affecting the brightness of the OSD. I think it controls the voltage divider on the OSD network. I don't think it is supposed to change much with the external RGB which is probably why changing those wasn't really helping the external RGB much. If you bump them to 820R you might be closer to where you want to be with the muxing. But it still might have a slight affect on external RGB, I am not certain.

Awesome. I'll go back to 820 and see how it goes. It's most likely that.

[retrozar]

How would I go about measuring the signals? Can I use a MM or would I need a scope?

What type of signal would indicate analog or digital RGB?

You will probably need a scope for this. It doesn't need to be too fancy, I think I got mine for under $100 and it works just fine for things like this. You will need to measure things like peak-to-peak voltage of the signals and whether there is any bias / steady dc voltage on the signal. If you measure the OSD and the signals peak close to 0.7v on solid colors then you will know that your external RGB needs to also need to peak around the same area. It will most likely be at least 0.5v or 0.7v ptp so you could always try that which you should be able to achieve with a 75ohm resistor to ground right at the inputs of the IC. With the blanking voltage, measure pin 7 of IC3102 when the OSD menu is on and it will show when voltage is used to trigger the switch. From there we can help you figure out a good voltage divider to use to try and match your external 5v blanking voltage. Pins 11,12,13 have a 0v which probably indicates that there is no DC bias so you might want to include a coupling capacitor on each of your external RGB lines. So you could try this
External RGB -> 75ohm to ground -> 220uf capacitor series (positive towards external side) -> Pins 8 9 10
Or severe the trace on pins 11 12 13 and send RGB / blanking there instead. Blanking voltage might be an estimate of like a 4.7k series to 2.2k to ground, but sometimes it is easier to use a potentiometer here so you can adjust it.

This is just an estimate, realistically you will want to prepare for several scenarios or resistor values. But that might be a good place to start if you wanting to do this.

So I finally got around to trying this but i didnt have much luck.

I first started by lifting one end of resistor R3181, R3182, & R3183 and inserted my RGB signal there without blanking. I was using the standard 75ohm/0.1uf resistor/cap termination for this. I was hoping that when i turned on the OSD menu i would see the image through the osd letters, which is what usually happens if a set is modable and you dont include the blanking signal. However, this was not the case. The OSD was still there but the letters were all in black & i didnt see any of the attached console image coming through. One thing i did find interesting is that when i switched on the console i was using to test, i would get a brief flash of a color picture. Not sure how this is possible as i was using a CSYNC cable so it must have been RGB? The image was too brief for me to tell. This happened when i used both the composite input and the svideo input (this set has only those 2 inputs & RF) for the sync signal.

I then tried removing R1384 and attaching the 5V blanking from the scart header to the IC. This resulted in a black screen but no image on all inputs, so im guessing 5V must be the correct voltage here? I then restored the 3 resistors and the blanking pin.

Looking at the solder mask diagram on page 25/26 of the service manual, i realized that pin 11, 12, & 13 are joined together on 1 plane. So i removed the IC and isolated those 3 pins as well as pin 14. I attached my RGB +blanking to pins 11-14. I got a very dim picture when i didnt have a scart cable connected from the SNES. When i plugged it in the TV worked like normal. But i had no OSD this time, and turning on the SNES didnt give me an image at all. Re-attaching pin 14 to the trace completely restored the OSD with color as well. But still the same when i had the SNES connected - no RGB image through the letters or on any of the inputs. The set seems to work fine with 11-13 out of circuit. If pins 11-13 are an unused RGB input im guessing you would have to enable it in the service menu somehow, and i dont see any reference of how to access that in the service manual.

Im not quite sure where to go from here. I have this scope but im not sure if itl work for further testing. If someone could give me a recommendation for an ideal scope to use that would be great. https://dn720005.ca.archive.org/0/items ... Manual.pdf

Service manual:
https://ia801302.us.archive.org/29/item ... MANUAL.pdf

One thing to note, the IC on this set is very strange - some sort of covered chip with components inside. Im tempted to try and open it up but not sure if it is UV sensitive or something. Some pictures of the IC and the dim RF input:
https://imgur.com/a/BHaBZmD

video of the very short color image using sd2snes. picture looks quite vibrant, maybe rgb?:
https://imgur.com/a/4YEzZ6a

[Delphius]

How would I go about measuring the signals? Can I use a MM or would I need a scope?

What type of signal would indicate analog or digital RGB?

You will probably need a scope for this. It doesn't need to be too fancy, I think I got mine for under $100 and it works just fine for things like this. You will need to measure things like peak-to-peak voltage of the signals and whether there is any bias / steady dc voltage on the signal. If you measure the OSD and the signals peak close to 0.7v on solid colors then you will know that your external RGB needs to also need to peak around the same area. It will most likely be at least 0.5v or 0.7v ptp so you could always try that which you should be able to achieve with a 75ohm resistor to ground right at the inputs of the IC. With the blanking voltage, measure pin 7 of IC3102 when the OSD menu is on and it will show when voltage is used to trigger the switch. From there we can help you figure out a good voltage divider to use to try and match your external 5v blanking voltage. Pins 11,12,13 have a 0v which probably indicates that there is no DC bias so you might want to include a coupling capacitor on each of your external RGB lines. So you could try this
External RGB -> 75ohm to ground -> 220uf capacitor series (positive towards external side) -> Pins 8 9 10
Or severe the trace on pins 11 12 13 and send RGB / blanking there instead. Blanking voltage might be an estimate of like a 4.7k series to 2.2k to ground, but sometimes it is easier to use a potentiometer here so you can adjust it.

This is just an estimate, realistically you will want to prepare for several scenarios or resistor values. But that might be a good place to start if you wanting to do this.

So I finally got around to trying this but i didnt have much luck.

I first started by lifting one end of resistor R3181, R3182, & R3183 and inserted my RGB signal there without blanking. I was using the standard 75ohm/0.1uf resistor/cap termination for this. I was hoping that when i turned on the OSD menu i would see the image through the osd letters, which is what usually happens if a set is modable and you dont include the blanking signal. However, this was not the case. The OSD was still there but the letters were all in black & i didnt see any of the attached console image coming through. One thing i did find interesting is that when i switched on the console i was using to test, i would get a brief flash of a color picture. Not sure how this is possible as i was using a CSYNC cable so it must have been RGB? The image was too brief for me to tell. This happened when i used both the composite input and the svideo input (this set has only those 2 inputs & RF) for the sync signal.

I then tried removing R1384 and attaching the 5V blanking from the scart header to the IC. This resulted in a black screen but no image on all inputs, so im guessing 5V must be the correct voltage here? I then restored the 3 resistors and the blanking pin.

Looking at the solder mask diagram on page 25/26 of the service manual, i realized that pin 11, 12, & 13 are joined together on 1 plane. So i removed the IC and isolated those 3 pins as well as pin 14. I attached my RGB +blanking to pins 11-14. I got a very dim picture when i didnt have a scart cable connected from the SNES. When i plugged it in the TV worked like normal. But i had no OSD this time, and turning on the SNES didnt give me an image at all. Re-attaching pin 14 to the trace completely restored the OSD with color as well. But still the same when i had the SNES connected - no RGB image through the letters or on any of the inputs. The set seems to work fine with 11-13 out of circuit. If pins 11-13 are an unused RGB input im guessing you would have to enable it in the service menu somehow, and i dont see any reference of how to access that in the service manual.

Im not quite sure where to go from here. I have this scope but im not sure if itl work for further testing. If someone could give me a recommendation for an ideal scope to use that would be great. https://dn720005.ca.archive.org/0/items ... Manual.pdf

Service manual:
https://ia801302.us.archive.org/29/item ... MANUAL.pdf

One thing to note, the IC on this set is very strange - some sort of covered chip with components inside. Im tempted to try and open it up but not sure if it is UV sensitive or something. Some pictures of the IC and the dim RF input:
https://imgur.com/a/BHaBZmD

video of the very short color image using sd2snes. picture looks quite vibrant, maybe rgb?:
https://imgur.com/a/4YEzZ6a

I think the key point here is that IC3102 is a buffered switch, not a muxing circuit. The connections you tried with pins 11-14 that you said you got a working RGB signal might be as good as it is going to get. It seems to me by your experiments that this switches between the two sets of RGB inputs on the left, or pins 7-10 vs 11-14. Then it mixes those to sets of RGB inputs with pins 1-5 which are carrying chroma. The trace you are removing from pins 11-14 is connecting those pins to ground. When you try to mix with pins 7-10 you are interferring with the buffer which is why you are getting the negative / black colors. So utilizing input to pins 11-14 might be the way to go. You will lose OSD when using external RGB, but OSD probably wont do anything for you unless you need to get into service mode.

Since the TV doesn't necessarily use RGB from any other source, there is a chance that pins 2-5 are not populated with anything and that only pin 1 is being used for Y. If this is the case you can try to inject the external RGB at pins 2-5 and see if OSD muxing works correctly there. If inputs 2-5 are populated with another RGB source then you might want to figure out what it is and see if you can disconnect it. Looking at the schematic it does seem to be tied to the RGB matrix for Y / composite. So you might be able to remove those from circuit which would remove your composite entirely and then replace it with RGB. But honestly unless you really need OSD for something when using external RGB I don't think this is worth it. The fact that you have a clean input from pins 11-14 utilizing a proper switch is technically ideal. The OSD will not control anything on the RGB signal. The OSD might be needed for service menu adjustments that can be handy for external RGB if the image isn't aligned from a result of csync processing. But you can probably tweak that by switching between the two modes although it is tedious.

Also, the IC is probably 5v tolerant to blanking, but it is still recommended that you add some current limiting with a resistor and potentially a pull down. If you measure the blanking from the OSD you will see what is proper for the IC and then you can determine the resistor values from that.

edit: also maybe check if when you have pins 11-14 active with RGB that the IC isn't mixing it with the composite signal. That seems to be what this chip does. If you end up with both signals, you might need to also create a way to safely ground the composite blank signal on pin 2. This might not be too tricky to do, but you will want to check what all is activating.

[retrozar]

You will probably need a scope for this. It doesn't need to be too fancy, I think I got mine for under $100 and it works just fine for things like this. You will need to measure things like peak-to-peak voltage of the signals and whether there is any bias / steady dc voltage on the signal. If you measure the OSD and the signals peak close to 0.7v on solid colors then you will know that your external RGB needs to also need to peak around the same area. It will most likely be at least 0.5v or 0.7v ptp so you could always try that which you should be able to achieve with a 75ohm resistor to ground right at the inputs of the IC. With the blanking voltage, measure pin 7 of IC3102 when the OSD menu is on and it will show when voltage is used to trigger the switch. From there we can help you figure out a good voltage divider to use to try and match your external 5v blanking voltage. Pins 11,12,13 have a 0v which probably indicates that there is no DC bias so you might want to include a coupling capacitor on each of your external RGB lines. So you could try this
External RGB -> 75ohm to ground -> 220uf capacitor series (positive towards external side) -> Pins 8 9 10
Or severe the trace on pins 11 12 13 and send RGB / blanking there instead. Blanking voltage might be an estimate of like a 4.7k series to 2.2k to ground, but sometimes it is easier to use a potentiometer here so you can adjust it.

This is just an estimate, realistically you will want to prepare for several scenarios or resistor values. But that might be a good place to start if you wanting to do this.

So I finally got around to trying this but i didnt have much luck.

I first started by lifting one end of resistor R3181, R3182, & R3183 and inserted my RGB signal there without blanking. I was using the standard 75ohm/0.1uf resistor/cap termination for this. I was hoping that when i turned on the OSD menu i would see the image through the osd letters, which is what usually happens if a set is modable and you dont include the blanking signal. However, this was not the case. The OSD was still there but the letters were all in black & i didnt see any of the attached console image coming through. One thing i did find interesting is that when i switched on the console i was using to test, i would get a brief flash of a color picture. Not sure how this is possible as i was using a CSYNC cable so it must have been RGB? The image was too brief for me to tell. This happened when i used both the composite input and the svideo input (this set has only those 2 inputs & RF) for the sync signal.

I then tried removing R1384 and attaching the 5V blanking from the scart header to the IC. This resulted in a black screen but no image on all inputs, so im guessing 5V must be the correct voltage here? I then restored the 3 resistors and the blanking pin.

Looking at the solder mask diagram on page 25/26 of the service manual, i realized that pin 11, 12, & 13 are joined together on 1 plane. So i removed the IC and isolated those 3 pins as well as pin 14. I attached my RGB +blanking to pins 11-14. I got a very dim picture when i didnt have a scart cable connected from the SNES. When i plugged it in the TV worked like normal. But i had no OSD this time, and turning on the SNES didnt give me an image at all. Re-attaching pin 14 to the trace completely restored the OSD with color as well. But still the same when i had the SNES connected - no RGB image through the letters or on any of the inputs. The set seems to work fine with 11-13 out of circuit. If pins 11-13 are an unused RGB input im guessing you would have to enable it in the service menu somehow, and i dont see any reference of how to access that in the service manual.

Im not quite sure where to go from here. I have this scope but im not sure if itl work for further testing. If someone could give me a recommendation for an ideal scope to use that would be great. https://dn720005.ca.archive.org/0/items ... Manual.pdf

Service manual:
https://ia801302.us.archive.org/29/item ... MANUAL.pdf

One thing to note, the IC on this set is very strange - some sort of covered chip with components inside. Im tempted to try and open it up but not sure if it is UV sensitive or something. Some pictures of the IC and the dim RF input:
https://imgur.com/a/BHaBZmD

video of the very short color image using sd2snes. picture looks quite vibrant, maybe rgb?:
https://imgur.com/a/4YEzZ6a

I think the key point here is that IC3102 is a buffered switch, not a muxing circuit. The connections you tried with pins 11-14 that you said you got a working RGB signal might be as good as it is going to get. It seems to me by your experiments that this switches between the two sets of RGB inputs on the left, or pins 7-10 vs 11-14. Then it mixes those to sets of RGB inputs with pins 1-5 which are carrying chroma. The trace you are removing from pins 11-14 is connecting those pins to ground. When you try to mix with pins 7-10 you are interferring with the buffer which is why you are getting the negative / black colors. So utilizing input to pins 11-14 might be the way to go. You will lose OSD when using external RGB, but OSD probably wont do anything for you unless you need to get into service mode.

Since the TV doesn't necessarily use RGB from any other source, there is a chance that pins 2-5 are not populated with anything and that only pin 1 is being used for Y. If this is the case you can try to inject the external RGB at pins 2-5 and see if OSD muxing works correctly there. If inputs 2-5 are populated with another RGB source then you might want to figure out what it is and see if you can disconnect it. Looking at the schematic it does seem to be tied to the RGB matrix for Y / composite. So you might be able to remove those from circuit which would remove your composite entirely and then replace it with RGB. But honestly unless you really need OSD for something when using external RGB I don't think this is worth it. The fact that you have a clean input from pins 11-14 utilizing a proper switch is technically ideal. The OSD will not control anything on the RGB signal. The OSD might be needed for service menu adjustments that can be handy for external RGB if the image isn't aligned from a result of csync processing. But you can probably tweak that by switching between the two modes although it is tedious.

Also, the IC is probably 5v tolerant to blanking, but it is still recommended that you add some current limiting with a resistor and potentially a pull down. If you measure the blanking from the OSD you will see what is proper for the IC and then you can determine the resistor values from that.

edit: also maybe check if when you have pins 11-14 active with RGB that the IC isn't mixing it with the composite signal. That seems to be what this chip does. If you end up with both signals, you might need to also create a way to safely ground the composite blank signal on pin 2. This might not be too tricky to do, but you will want to check what all is activating.

So the above may be a bit unclear as i wrote it in haste. I was able to try a few more things based on what you suggested however i still wasn't able to achieve an RGB output. Heres what ive tested so far:

Pins 7-10: I lifted the 3 resistors on pins 7-9 and left the blanking intact. I was able to get a brief image (which i linked in the video above) but it went to a blank screen after. The OSD letters were there but all in black. Lifting pin 10 and applying my blanking signal gave me a totally black screen on all inputs but no picture.

Pins 11-14: I lifted all 4 pins. Interesting to note here that when i first turned the set (with no console connected) it was on the RF input. Instead of the white snowy affect it show a mostly black screen with various green snowy effects. Not sure if this is significant. When i attached the scart cable to the tv, the snowy RF picture when back to normal. But turning on the console had no effect - and i did not get a brief flash of a picture like i did on the previous 4 pins above. Keeping pin 2 in circuit and applying my signal didn't work either.

Pins 2-5 & Pin 1: I lifted pins 2-5 and tried inserting my signal again. This caused the OSD letters to stop appearing when i did not have a scart cable connected. When i connected a console to the TV the OSD letters were viewable like normal. No picture this time as well. This also caused the composite input to stop working, so i think your hypothesis above is correct. Pin 1 goes into a service switch and flipping it up or down had no effect on the image when i tried it. It also goes into jumper 305 which can be cut to disable the Y signal. However this also seemed to have little effect and I still wasn't able to get an RGB image.

I then decided to try lifting all 3 inputs (so keeping 12-13 pins out of circuit) and trying them individually with the others out of circuit. Still no luck. I also tried various combinations of leaving one or 2 inputs in circuit or trying to apply my signal to different blanking pins. Still nothing.

So im not really sure where to go from here. Maybe scoping the signals would give some sort of idea? If someone can give me a good tutorial for using a scope that would help.

[Delphius]

So I finally got around to trying this but i didnt have much luck.

I first started by lifting one end of resistor R3181, R3182, & R3183 and inserted my RGB signal there without blanking. I was using the standard 75ohm/0.1uf resistor/cap termination for this. I was hoping that when i turned on the OSD menu i would see the image through the osd letters, which is what usually happens if a set is modable and you dont include the blanking signal. However, this was not the case. The OSD was still there but the letters were all in black & i didnt see any of the attached console image coming through. One thing i did find interesting is that when i switched on the console i was using to test, i would get a brief flash of a color picture. Not sure how this is possible as i was using a CSYNC cable so it must have been RGB? The image was too brief for me to tell. This happened when i used both the composite input and the svideo input (this set has only those 2 inputs & RF) for the sync signal.

I then tried removing R1384 and attaching the 5V blanking from the scart header to the IC. This resulted in a black screen but no image on all inputs, so im guessing 5V must be the correct voltage here? I then restored the 3 resistors and the blanking pin.

Looking at the solder mask diagram on page 25/26 of the service manual, i realized that pin 11, 12, & 13 are joined together on 1 plane. So i removed the IC and isolated those 3 pins as well as pin 14. I attached my RGB +blanking to pins 11-14. I got a very dim picture when i didnt have a scart cable connected from the SNES. When i plugged it in the TV worked like normal. But i had no OSD this time, and turning on the SNES didnt give me an image at all. Re-attaching pin 14 to the trace completely restored the OSD with color as well. But still the same when i had the SNES connected - no RGB image through the letters or on any of the inputs. The set seems to work fine with 11-13 out of circuit. If pins 11-13 are an unused RGB input im guessing you would have to enable it in the service menu somehow, and i dont see any reference of how to access that in the service manual.

Im not quite sure where to go from here. I have this scope but im not sure if itl work for further testing. If someone could give me a recommendation for an ideal scope to use that would be great. https://dn720005.ca.archive.org/0/items ... Manual.pdf

Service manual:
https://ia801302.us.archive.org/29/item ... MANUAL.pdf

One thing to note, the IC on this set is very strange - some sort of covered chip with components inside. Im tempted to try and open it up but not sure if it is UV sensitive or something. Some pictures of the IC and the dim RF input:
https://imgur.com/a/BHaBZmD

video of the very short color image using sd2snes. picture looks quite vibrant, maybe rgb?:
https://imgur.com/a/4YEzZ6a

I think the key point here is that IC3102 is a buffered switch, not a muxing circuit. The connections you tried with pins 11-14 that you said you got a working RGB signal might be as good as it is going to get. It seems to me by your experiments that this switches between the two sets of RGB inputs on the left, or pins 7-10 vs 11-14. Then it mixes those to sets of RGB inputs with pins 1-5 which are carrying chroma. The trace you are removing from pins 11-14 is connecting those pins to ground. When you try to mix with pins 7-10 you are interferring with the buffer which is why you are getting the negative / black colors. So utilizing input to pins 11-14 might be the way to go. You will lose OSD when using external RGB, but OSD probably wont do anything for you unless you need to get into service mode.

Since the TV doesn't necessarily use RGB from any other source, there is a chance that pins 2-5 are not populated with anything and that only pin 1 is being used for Y. If this is the case you can try to inject the external RGB at pins 2-5 and see if OSD muxing works correctly there. If inputs 2-5 are populated with another RGB source then you might want to figure out what it is and see if you can disconnect it. Looking at the schematic it does seem to be tied to the RGB matrix for Y / composite. So you might be able to remove those from circuit which would remove your composite entirely and then replace it with RGB. But honestly unless you really need OSD for something when using external RGB I don't think this is worth it. The fact that you have a clean input from pins 11-14 utilizing a proper switch is technically ideal. The OSD will not control anything on the RGB signal. The OSD might be needed for service menu adjustments that can be handy for external RGB if the image isn't aligned from a result of csync processing. But you can probably tweak that by switching between the two modes although it is tedious.

Also, the IC is probably 5v tolerant to blanking, but it is still recommended that you add some current limiting with a resistor and potentially a pull down. If you measure the blanking from the OSD you will see what is proper for the IC and then you can determine the resistor values from that.

edit: also maybe check if when you have pins 11-14 active with RGB that the IC isn't mixing it with the composite signal. That seems to be what this chip does. If you end up with both signals, you might need to also create a way to safely ground the composite blank signal on pin 2. This might not be too tricky to do, but you will want to check what all is activating.

So the above may be a bit unclear as i wrote it in haste. I was able to try a few more things based on what you suggested however i still wasn't able to achieve an RGB output. Heres what ive tested so far:

Pins 7-10: I lifted the 3 resistors on pins 7-9 and left the blanking intact. I was able to get a brief image (which i linked in the video above) but it went to a blank screen after. The OSD letters were there but all in black. Lifting pin 10 and applying my blanking signal gave me a totally black screen on all inputs but no picture.

Pins 11-14: I lifted all 4 pins. Interesting to note here that when i first turned the set (with no console connected) it was on the RF input. Instead of the white snowy affect it show a mostly black screen with various green snowy effects. Not sure if this is significant. When i attached the scart cable to the tv, the snowy RF picture when back to normal. But turning on the console had no effect - and i did not get a brief flash of a picture like i did on the previous 4 pins above. Keeping pin 2 in circuit and applying my signal didn't work either.

Pins 2-5 & Pin 1: I lifted pins 2-5 and tried inserting my signal again. This caused the OSD letters to stop appearing when i did not have a scart cable connected. When i connected a console to the TV the OSD letters were viewable like normal. No picture this time as well. This also caused the composite input to stop working, so i think your hypothesis above is correct. Pin 1 goes into a service switch and flipping it up or down had no effect on the image when i tried it. It also goes into jumper 305 which can be cut to disable the Y signal. However this also seemed to have little effect and I still wasn't able to get an RGB image.

I then decided to try lifting all 3 inputs (so keeping 12-13 pins out of circuit) and trying them individually with the others out of circuit. Still no luck. I also tried various combinations of leaving one or 2 inputs in circuit or trying to apply my signal to different blanking pins. Still nothing.

So im not really sure where to go from here. Maybe scoping the signals would give some sort of idea? If someone can give me a good tutorial for using a scope that would help.

Ok interesting. One thing that is not clear from your notes is how you are connecting blanking signal from console / scart? Are you connecting it to the blanking pins? What voltage? Is it through resistors? The blanking signal is going to be important to add with your RGB lines on any of those signals, and if you aren't giving it enough then it won't trigger the switch to use those channels. Usually don't give it a full 5v, but move it through a voltage divider. Measure the fast blanking lines specifically on Pin 2 when normal usage is happening, then also pin 7 when the OSD is engaged. This will tell you the target voltage to trigger the switching. If you are using a voltage divider already, maybe it needs adjustment.

Once I have more information about that we might be able to track down what is going on.

[retrozar]

I think the key point here is that IC3102 is a buffered switch, not a muxing circuit. The connections you tried with pins 11-14 that you said you got a working RGB signal might be as good as it is going to get. It seems to me by your experiments that this switches between the two sets of RGB inputs on the left, or pins 7-10 vs 11-14. Then it mixes those to sets of RGB inputs with pins 1-5 which are carrying chroma. The trace you are removing from pins 11-14 is connecting those pins to ground. When you try to mix with pins 7-10 you are interferring with the buffer which is why you are getting the negative / black colors. So utilizing input to pins 11-14 might be the way to go. You will lose OSD when using external RGB, but OSD probably wont do anything for you unless you need to get into service mode.

Since the TV doesn't necessarily use RGB from any other source, there is a chance that pins 2-5 are not populated with anything and that only pin 1 is being used for Y. If this is the case you can try to inject the external RGB at pins 2-5 and see if OSD muxing works correctly there. If inputs 2-5 are populated with another RGB source then you might want to figure out what it is and see if you can disconnect it. Looking at the schematic it does seem to be tied to the RGB matrix for Y / composite. So you might be able to remove those from circuit which would remove your composite entirely and then replace it with RGB. But honestly unless you really need OSD for something when using external RGB I don't think this is worth it. The fact that you have a clean input from pins 11-14 utilizing a proper switch is technically ideal. The OSD will not control anything on the RGB signal. The OSD might be needed for service menu adjustments that can be handy for external RGB if the image isn't aligned from a result of csync processing. But you can probably tweak that by switching between the two modes although it is tedious.

Also, the IC is probably 5v tolerant to blanking, but it is still recommended that you add some current limiting with a resistor and potentially a pull down. If you measure the blanking from the OSD you will see what is proper for the IC and then you can determine the resistor values from that.

edit: also maybe check if when you have pins 11-14 active with RGB that the IC isn't mixing it with the composite signal. That seems to be what this chip does. If you end up with both signals, you might need to also create a way to safely ground the composite blank signal on pin 2. This might not be too tricky to do, but you will want to check what all is activating.

So the above may be a bit unclear as i wrote it in haste. I was able to try a few more things based on what you suggested however i still wasn't able to achieve an RGB output. Heres what ive tested so far:

Pins 7-10: I lifted the 3 resistors on pins 7-9 and left the blanking intact. I was able to get a brief image (which i linked in the video above) but it went to a blank screen after. The OSD letters were there but all in black. Lifting pin 10 and applying my blanking signal gave me a totally black screen on all inputs but no picture.

Pins 11-14: I lifted all 4 pins. Interesting to note here that when i first turned the set (with no console connected) it was on the RF input. Instead of the white snowy affect it show a mostly black screen with various green snowy effects. Not sure if this is significant. When i attached the scart cable to the tv, the snowy RF picture when back to normal. But turning on the console had no effect - and i did not get a brief flash of a picture like i did on the previous 4 pins above. Keeping pin 2 in circuit and applying my signal didn't work either.

Pins 2-5 & Pin 1: I lifted pins 2-5 and tried inserting my signal again. This caused the OSD letters to stop appearing when i did not have a scart cable connected. When i connected a console to the TV the OSD letters were viewable like normal. No picture this time as well. This also caused the composite input to stop working, so i think your hypothesis above is correct. Pin 1 goes into a service switch and flipping it up or down had no effect on the image when i tried it. It also goes into jumper 305 which can be cut to disable the Y signal. However this also seemed to have little effect and I still wasn't able to get an RGB image.

I then decided to try lifting all 3 inputs (so keeping 12-13 pins out of circuit) and trying them individually with the others out of circuit. Still no luck. I also tried various combinations of leaving one or 2 inputs in circuit or trying to apply my signal to different blanking pins. Still nothing.

So im not really sure where to go from here. Maybe scoping the signals would give some sort of idea? If someone can give me a good tutorial for using a scope that would help.

Ok interesting. One thing that is not clear from your notes is how you are connecting blanking signal from console / scart? Are you connecting it to the blanking pins? What voltage? Is it through resistors? The blanking signal is going to be important to add with your RGB lines on any of those signals, and if you aren't giving it enough then it won't trigger the switch to use those channels. Usually don't give it a full 5v, but move it through a voltage divider. Measure the fast blanking lines specifically on Pin 2 when normal usage is happening, then also pin 7 when the OSD is engaged. This will tell you the target voltage to trigger the switching. If you are using a voltage divider already, maybe it needs adjustment.

Once I have more information about that we might be able to track down what is going on.

I am connecting it directly from pin 16 of the Scart output from the console, so probably 5V exactly?

I will research how to scope the signals i guess. Just want to make sure now to blow out the IC or something.

[Delphius]

So the above may be a bit unclear as i wrote it in haste. I was able to try a few more things based on what you suggested however i still wasn't able to achieve an RGB output. Heres what ive tested so far:

Pins 7-10: I lifted the 3 resistors on pins 7-9 and left the blanking intact. I was able to get a brief image (which i linked in the video above) but it went to a blank screen after. The OSD letters were there but all in black. Lifting pin 10 and applying my blanking signal gave me a totally black screen on all inputs but no picture.

Pins 11-14: I lifted all 4 pins. Interesting to note here that when i first turned the set (with no console connected) it was on the RF input. Instead of the white snowy affect it show a mostly black screen with various green snowy effects. Not sure if this is significant. When i attached the scart cable to the tv, the snowy RF picture when back to normal. But turning on the console had no effect - and i did not get a brief flash of a picture like i did on the previous 4 pins above. Keeping pin 2 in circuit and applying my signal didn't work either.

Pins 2-5 & Pin 1: I lifted pins 2-5 and tried inserting my signal again. This caused the OSD letters to stop appearing when i did not have a scart cable connected. When i connected a console to the TV the OSD letters were viewable like normal. No picture this time as well. This also caused the composite input to stop working, so i think your hypothesis above is correct. Pin 1 goes into a service switch and flipping it up or down had no effect on the image when i tried it. It also goes into jumper 305 which can be cut to disable the Y signal. However this also seemed to have little effect and I still wasn't able to get an RGB image.

I then decided to try lifting all 3 inputs (so keeping 12-13 pins out of circuit) and trying them individually with the others out of circuit. Still no luck. I also tried various combinations of leaving one or 2 inputs in circuit or trying to apply my signal to different blanking pins. Still nothing.

So im not really sure where to go from here. Maybe scoping the signals would give some sort of idea? If someone can give me a good tutorial for using a scope that would help.

Ok interesting. One thing that is not clear from your notes is how you are connecting blanking signal from console / scart? Are you connecting it to the blanking pins? What voltage? Is it through resistors? The blanking signal is going to be important to add with your RGB lines on any of those signals, and if you aren't giving it enough then it won't trigger the switch to use those channels. Usually don't give it a full 5v, but move it through a voltage divider. Measure the fast blanking lines specifically on Pin 2 when normal usage is happening, then also pin 7 when the OSD is engaged. This will tell you the target voltage to trigger the switching. If you are using a voltage divider already, maybe it needs adjustment.

Once I have more information about that we might be able to track down what is going on.

I am connecting it directly from pin 16 of the Scart output from the console, so probably 5V exactly?

I will research how to scope the signals i guess. Just want to make sure now to blow out the IC or something.

In general they should be 5v tolerant, but I think it is wise to just put it over the triggering threshold. When you use a multimeter just measure in DC mode at the blanking pins with the normal OSD and runtime blanking that is used. Sometimes you only need around 3v.

Regardless, 5v should be triggering the blanking to switch so we will need to think about what it really happening. I think we should focus on pins 7-10 first from the OSD. If you lifted the resistors here and brought the OSD out of circuit, I wouldn't expect the behavior of it flashing on and off. But maybe the blanking voltage from OSD is turning off. It could be a biasing issue as well, but you mentioned you are are using coupling capacitors on the RGB channels from your SCART correct? If the line is isolated from the OSD and you are using a 0.1uf coupling capacitor, you could try higher coupling or maybe even removing the coupling at altogether. I am noticing that none of the other inputs to that IC are AC coupled. Maybe before trying that you can also measure the DC voltage from the OSD pin RGB outputs. If they are showing DC voltage, and they do not have AC coupling, then the DC voltage might be necessary to bias that IC. Only speculating here so I would measure first. But we need to figure out how the stock circuits are interacting with that IC.

[nazgulone]

Okay, so I'm going to mod my Samsung SMC-150FN CCTV this weekend and I need someone to spot check me at least from a high level (i.e. I'm not worried about voltages and resistor values right this second, just need to know that I'm on the right track.)

I found the Service Manual of the SMC-152FP, which is essentially the same (150 is 2 input, 152 is 4 input, FN is NTSC, FP is PAL).

The jungle chip is a Philips TDA9380PS/N3. It looks like all the OSD processing is done within the jungle chip, so I can't just splice into the OSD lines, BUT it does have empty RGB pins at 46, 47, and 48.

Pin 45 looks like Fast Blanking, which is required to enable the internal RGB input. HOWEVER, it looks from the Data Sheet of the chip that in order for fast blanking to be active, data byte 6 of Control 0 at Slave address 2A, known as IE2, needs to be set to 1, potentially at some interval, though I doubt they apply that value after boot? I would imagine that by default, the fast blanking byte is set to 0.

I've used Arduinos before, and it seems to me like I just have to inject that value on the I2C bus and then activate pin 45 to allow me to use 45, 46, and 47 as RGB, right?

And as a bonus, it looks like if I can toggle the value at D2 of 2B (AKA "YUV" on Control 1), I can swap between RGB and YUV, no?

Here is part of the schematic diagram from the service manual:

Spoiler

Here is the chart of values from the data sheet of the jungle chip:

Spoiler

Here is the description of the values from the same data sheet:

Spoiler

Here is the description of the pins from the data sheet:

Spoiler

Link to the data sheet: https://www.alldatasheet.com/datasheet- ... ASHN2.html

Am I way far off base?

I have the Samsung SMC 152FP model, but I can’t find the service manual anywhere. I see that you managed to get it—would you mind telling me where you downloaded it, or uploading it somewhere so I can access it?

Thank you very much.

[retrozar]

Ok interesting. One thing that is not clear from your notes is how you are connecting blanking signal from console / scart? Are you connecting it to the blanking pins? What voltage? Is it through resistors? The blanking signal is going to be important to add with your RGB lines on any of those signals, and if you aren't giving it enough then it won't trigger the switch to use those channels. Usually don't give it a full 5v, but move it through a voltage divider. Measure the fast blanking lines specifically on Pin 2 when normal usage is happening, then also pin 7 when the OSD is engaged. This will tell you the target voltage to trigger the switching. If you are using a voltage divider already, maybe it needs adjustment.

Once I have more information about that we might be able to track down what is going on.

I am connecting it directly from pin 16 of the Scart output from the console, so probably 5V exactly?

I will research how to scope the signals i guess. Just want to make sure now to blow out the IC or something.

In general they should be 5v tolerant, but I think it is wise to just put it over the triggering threshold. When you use a multimeter just measure in DC mode at the blanking pins with the normal OSD and runtime blanking that is used. Sometimes you only need around 3v.

Regardless, 5v should be triggering the blanking to switch so we will need to think about what it really happening. I think we should focus on pins 7-10 first from the OSD. If you lifted the resistors here and brought the OSD out of circuit, I wouldn't expect the behavior of it flashing on and off. But maybe the blanking voltage from OSD is turning off. It could be a biasing issue as well, but you mentioned you are are using coupling capacitors on the RGB channels from your SCART correct? If the line is isolated from the OSD and you are using a 0.1uf coupling capacitor, you could try higher coupling or maybe even removing the coupling at altogether. I am noticing that none of the other inputs to that IC are AC coupled. Maybe before trying that you can also measure the DC voltage from the OSD pin RGB outputs. If they are showing DC voltage, and they do not have AC coupling, then the DC voltage might be necessary to bias that IC. Only speculating here so I would measure first. But we need to figure out how the stock circuits are interacting with that IC.

I measured the pin with my MM and got some interesting results. The DC setting on mine only goes to 20v or 2v so I had to use the 2v setting to get anything as the voltages were too low otherwise:

Pin 7 .049
Pin 8 0.12
Pin 9 0.19
Pin 10 .006

I also tried removing the caps and just connecting with resistors only. With or without blanking in circuit I still had no luck sadly. Interesting to note that I did not get the brief flash of an image when I tried it this way.

[Delphius]

I am connecting it directly from pin 16 of the Scart output from the console, so probably 5V exactly?

I will research how to scope the signals i guess. Just want to make sure now to blow out the IC or something.

In general they should be 5v tolerant, but I think it is wise to just put it over the triggering threshold. When you use a multimeter just measure in DC mode at the blanking pins with the normal OSD and runtime blanking that is used. Sometimes you only need around 3v.

Regardless, 5v should be triggering the blanking to switch so we will need to think about what it really happening. I think we should focus on pins 7-10 first from the OSD. If you lifted the resistors here and brought the OSD out of circuit, I wouldn't expect the behavior of it flashing on and off. But maybe the blanking voltage from OSD is turning off. It could be a biasing issue as well, but you mentioned you are are using coupling capacitors on the RGB channels from your SCART correct? If the line is isolated from the OSD and you are using a 0.1uf coupling capacitor, you could try higher coupling or maybe even removing the coupling at altogether. I am noticing that none of the other inputs to that IC are AC coupled. Maybe before trying that you can also measure the DC voltage from the OSD pin RGB outputs. If they are showing DC voltage, and they do not have AC coupling, then the DC voltage might be necessary to bias that IC. Only speculating here so I would measure first. But we need to figure out how the stock circuits are interacting with that IC.

I measured the pin with my MM and got some interesting results. The DC setting on mine only goes to 20v or 2v so I had to use the 2v setting to get anything as the voltages were too low otherwise:

Pin 7 .049
Pin 8 0.12
Pin 9 0.19
Pin 10 .006

I also tried removing the caps and just connecting with resistors only. With or without blanking in circuit I still had no luck sadly. Interesting to note that I did not get the brief flash of an image when I tried it this way.

Ok I would keep your caps in circuit for now (you are referring to the caps on your external RGB correct?). The resistors on OSD R3181 - R 3183 are remove from circuit correct (removing OSD from the circuit). When measuring Pin 7 you need to measure it with R3184 in circuit and with OSD turned on. It should give you the voltage for the blanking being used from the OSD.

[retrozar]

In general they should be 5v tolerant, but I think it is wise to just put it over the triggering threshold. When you use a multimeter just measure in DC mode at the blanking pins with the normal OSD and runtime blanking that is used. Sometimes you only need around 3v.

Regardless, 5v should be triggering the blanking to switch so we will need to think about what it really happening. I think we should focus on pins 7-10 first from the OSD. If you lifted the resistors here and brought the OSD out of circuit, I wouldn't expect the behavior of it flashing on and off. But maybe the blanking voltage from OSD is turning off. It could be a biasing issue as well, but you mentioned you are are using coupling capacitors on the RGB channels from your SCART correct? If the line is isolated from the OSD and you are using a 0.1uf coupling capacitor, you could try higher coupling or maybe even removing the coupling at altogether. I am noticing that none of the other inputs to that IC are AC coupled. Maybe before trying that you can also measure the DC voltage from the OSD pin RGB outputs. If they are showing DC voltage, and they do not have AC coupling, then the DC voltage might be necessary to bias that IC. Only speculating here so I would measure first. But we need to figure out how the stock circuits are interacting with that IC.

I measured the pin with my MM and got some interesting results. The DC setting on mine only goes to 20v or 2v so I had to use the 2v setting to get anything as the voltages were too low otherwise:

Pin 7 .049
Pin 8 0.12
Pin 9 0.19
Pin 10 .006

I also tried removing the caps and just connecting with resistors only. With or without blanking in circuit I still had no luck sadly. Interesting to note that I did not get the brief flash of an image when I tried it this way.

Ok I would keep your caps in circuit for now (you are referring to the caps on your external RGB correct?). The resistors on OSD R3181 - R 3183 are remove from circuit correct (removing OSD from the circuit). When measuring Pin 10 you need to measure it with R3184 in circuit and with OSD turned on. It should give you the voltage for the blanking being used from the OSD.

Yes, the caps on the external RGB. The measurements are from before i removed anything from circuit.

[Delphius]

I measured the pin with my MM and got some interesting results. The DC setting on mine only goes to 20v or 2v so I had to use the 2v setting to get anything as the voltages were too low otherwise:

Pin 7 .049
Pin 8 0.12
Pin 9 0.19
Pin 10 .006

I also tried removing the caps and just connecting with resistors only. With or without blanking in circuit I still had no luck sadly. Interesting to note that I did not get the brief flash of an image when I tried it this way.

Ok I would keep your caps in circuit for now (you are referring to the caps on your external RGB correct?). The resistors on OSD R3181 - R 3183 are remove from circuit correct (removing OSD from the circuit). When measuring Pin 10 you need to measure it with R3184 in circuit and with OSD turned on. It should give you the voltage for the blanking being used from the OSD.

Yes, the caps on the external RGB. The measurements are from before i removed anything from circuit.

Ok interesting. I am just confused because pin 7 is the fast blanking for the OSD. When the OSD is on it should be sending voltage to trigger the IC to activate those channels. .049v does not make sense if the OSD was activated during this measurement.

[retrozar]

Ok I would keep your caps in circuit for now (you are referring to the caps on your external RGB correct?). The resistors on OSD R3181 - R 3183 are remove from circuit correct (removing OSD from the circuit). When measuring Pin 10 you need to measure it with R3184 in circuit and with OSD turned on. It should give you the voltage for the blanking being used from the OSD.

Yes, the caps on the external RGB. The measurements are from before i removed anything from circuit.

Ok interesting. I am just confused because pin 7 is the fast blanking for the OSD. When the OSD is on it should be sending voltage to trigger the IC to activate those channels. .049v does not make sense if the OSD was activated during this measurement.

I thought that was strange as well. But I measured before the OSD was on and it was at 0. After I turn the menu on it just goes to those values. Not sure why it is so low. I'm measuring at the pin directly with everything in circuit.

[spencemo]

Hey folks,

Looking to do my first RBG mod. I have a Panasonic CT-2089VYD I picked up from my university, and I can't seem to find the jungle chip in the service manual (https://www.manualslib.com/manual/26317 ... =36#manual). Is video signal processing done by the MPU for this model (M65580MAPB00)? If so, I'm guessing I would need to Mux? Any guidance would be helpful!

[buttersoft]

Hi Buttersoft, I’m also in Australia. I have acquired a TV-348 (14” Samsung) which composite in/out on the back.
It also uses the same Philips jungle IC. 4481. Does this mean my set will also have RGB disabled in the EEPROM?

@MArkOZLAD would be in a much better place to answer this. He managed to get a remote and from there went int othe service menu and took the set out of "hotel mode", IIRC. Unless it was out of hotel mode. Either way he got the scart working. I was unable to replciate his feat, even with his help, however :/

[miyoso]

Hey guys, can I bump this one...

Service manual here.

Still not working, and theres some things that im unsure of:

1. Am i using the right pin for Sync?

2. Am i applying voltage to the correct pin (RGBIN)?

3. When checking the voltage after voltage division, the voltage is correct, but the moment i connect it to RGBIN the voltage tanks to 0.0004mV. Would that mean there is a circuit attached to the RGBIN? should i perhaps be pulling that leg out?

Did you ever got this to work? I'm currently trying to mod this chasis (L9.1A) with a TDA8843 too with no luck

[IOA]

Hey guys, first time modder here. Before I put my iron to the board, I was hoping someone could give me some pointers for an injection point on this Philips 19PR21 C121.

It appears to use a M37272M6H-062FP MICOM and M612030 for the jungle chip

I'm looking at pins 42/41/40 for R/G/B respectively, which appear to branch out to the center 3 series of resistors above it and to the left:



Does this seem like a sensible place to inject my signal, AFTER all the resistors? This board is totally cramped and tiny (I know, probably not great for my first run), but I was hoping someone here might have attempted something similar and might be able to "sanity check" my reasoning. If so...it looks like I have some plenty big pads to solder to, and then is just a matter of finding a 5v source to tap into for the blanking signal.

If it matters, I intend to connect my 15khz GroovyArcade setup to this (same 1.4v -> 0.7v 75ohm resistor needed?) via VGA.

Thanks in advance!