TV RGB mod thread

[vol.2]

Hey guys. Got this Samsung 36 inch monster I'm trying to Mux mod.

Can someone confirm if I did the calculations correctly for the inline resistors and where to inject the signals?

Link with diagram and schematics: https://imgur.com/gallery/OUtdfW0

TDA8375 Jungle
Chassis Sct55a

Thank you

What's the deal with the IC in your pic? You wrote TDA8375, but pic shows Z89313.

Are you saying this is the same IC, or did you open yours up to find the TDA IC instead? Or is this the video IC that outputs the OSD signal and not the input? Sorry, I can't be bothered to double check your schematic for the answer to this apparent conflict.

[Anonygoose]

Hey guys. Got this Samsung 36 inch monster I'm trying to Mux mod.

Can someone confirm if I did the calculations correctly for the inline resistors and where to inject the signals?

Link with diagram and schematics: https://imgur.com/gallery/OUtdfW0

TDA8375 Jungle
Chassis Sct55a

Thank you

What's the deal with the IC in your pic? You wrote TDA8375, but pic shows Z89313.

Are you saying this is the same IC, or did you open yours up to find the TDA IC instead? Or is this the video IC that outputs the OSD signal and not the input? Sorry, I can't be bothered to double check your schematic for the answer to this apparent conflict.

Hey. Sorry, should have clarified in my post. TDA8375 is the jungle which is the 3rd pic where I will inject RGB, and Z89313 outputs the OSD signal to the jungle.

[vol.2]

Hey. Sorry, should have clarified in my post. TDA8375 is the jungle which is the 3rd pic where I will inject RGB, and Z89313 outputs the OSD signal to the jungle.

No worries.

Ok. You need to look up the datasheet for the TDA837 series (includes the 8375) ICs.

Unfortunately, you might not be able to do this one, because the IC is I^2C controlled. The OSD input is about 0.7Vpp, which should probably be okay for RGB, but the problem I can see is the blanking. I'm not sure how the IC would know or be told to turn on blanking all the time without reprogramming the onboard memory. In typical RGB mods, the method is to inject 5V at the blanking pin for the OSD, which tells the jungle IC to blank the video and inject OSD input all the time. Without that, I'm not sure what would happen exactly. According to the datasheet, the RGB blanking is set internal to the IC. Currently, it's set to blank in such a way as to make the display appear on top of the signal present at the video input. I believe that you would have to rewrite the ROM used by the IC to have that on all the time. Unless there is a setting in the service manual for the TV to change that bit.

[Anonygoose]

Hey. Sorry, should have clarified in my post. TDA8375 is the jungle which is the 3rd pic where I will inject RGB, and Z89313 outputs the OSD signal to the jungle.

No worries.

Ok. You need to look up the datasheet for the TDA837 series (includes the 8375) ICs.

Unfortunately, you might not be able to do this one, because the IC is I^2C controlled. The OSD input is about 0.7Vpp, which should probably be okay for RGB, but the problem I can see is the blanking. I'm not sure how the IC would know or be told to turn on blanking all the time without reprogramming the onboard memory. In typical RGB mods, the method is to inject 5V at the blanking pin for the OSD, which tells the jungle IC to blank the video and inject OSD input all the time. Without that, I'm not sure what would happen exactly. According to the datasheet, the RGB blanking is set internal to the IC. Currently, it's set to blank in such a way as to make the display appear on top of the signal present at the video input. I believe that you would have to rewrite the ROM used by the IC to have that on all the time. Unless there is a setting in the service manual for the TV to change that bit.

Interesting. I've seen a couple of examples in this thread of people successfully RGB modding sets with that same jungle IC. Also the schematics show 2 scart inputs, but my chassis don't have them. The service manual I'm looking at shows an option to set scart to on or off in the service menu. With that said, do I still need to supply blanking with 5V? Or setting it to on from the menu is enough?

Also could you please confirm my diagram, I'm not sure I've used Sunthar's calculator correctly to determine the resistor values and which ones on the main board to remove.

Really appreciate your help.

[Delphius]

Hey. Sorry, should have clarified in my post. TDA8375 is the jungle which is the 3rd pic where I will inject RGB, and Z89313 outputs the OSD signal to the jungle.

No worries.

Ok. You need to look up the datasheet for the TDA837 series (includes the 8375) ICs.

Unfortunately, you might not be able to do this one, because the IC is I^2C controlled. The OSD input is about 0.7Vpp, which should probably be okay for RGB, but the problem I can see is the blanking. I'm not sure how the IC would know or be told to turn on blanking all the time without reprogramming the onboard memory. In typical RGB mods, the method is to inject 5V at the blanking pin for the OSD, which tells the jungle IC to blank the video and inject OSD input all the time. Without that, I'm not sure what would happen exactly. According to the datasheet, the RGB blanking is set internal to the IC. Currently, it's set to blank in such a way as to make the display appear on top of the signal present at the video input. I believe that you would have to rewrite the ROM used by the IC to have that on all the time. Unless there is a setting in the service manual for the TV to change that bit.

Interesting. I've seen a couple of examples in this thread of people successfully RGB modding sets with that same jungle IC. Also the schematics show 2 scart inputs, but my chassis don't have them. The service manual I'm looking at shows an option to set scart to on or off in the service menu. With that said, do I still need to supply blanking with 5V? Or setting it to on from the menu is enough?

Also could you please confirm my diagram, I'm not sure I've used Sunthar's calculator correctly to determine the resistor values and which ones on the main board to remove.

Really appreciate your help.

Overall your calculator is correct, but it depends on how your TV in configured. Near the jungle chip there is a jumper option to connect the OSD RGB to jungle chip directly, or use the switching system. If you have those jumpers closed then I would assume that your injection point is correct, and your calculations look right. But if those jumpers are open and the signal is passing through the TEA5114A then this might complicate things a little more. Also check if R282 R284 R286 is populated. If the switch is being used then you will need to check if it has its own bias and buffer. It mostly likely does which is why they have the pull downs on R282 R284 and R286. If you can verify what open is set we might be able to figure out some next steps.

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

[Anonygoose]

No worries.

Ok. You need to look up the datasheet for the TDA837 series (includes the 8375) ICs.

Unfortunately, you might not be able to do this one, because the IC is I^2C controlled. The OSD input is about 0.7Vpp, which should probably be okay for RGB, but the problem I can see is the blanking. I'm not sure how the IC would know or be told to turn on blanking all the time without reprogramming the onboard memory. In typical RGB mods, the method is to inject 5V at the blanking pin for the OSD, which tells the jungle IC to blank the video and inject OSD input all the time. Without that, I'm not sure what would happen exactly. According to the datasheet, the RGB blanking is set internal to the IC. Currently, it's set to blank in such a way as to make the display appear on top of the signal present at the video input. I believe that you would have to rewrite the ROM used by the IC to have that on all the time. Unless there is a setting in the service manual for the TV to change that bit.

Interesting. I've seen a couple of examples in this thread of people successfully RGB modding sets with that same jungle IC. Also the schematics show 2 scart inputs, but my chassis don't have them. The service manual I'm looking at shows an option to set scart to on or off in the service menu. With that said, do I still need to supply blanking with 5V? Or setting it to on from the menu is enough?

Also could you please confirm my diagram, I'm not sure I've used Sunthar's calculator correctly to determine the resistor values and which ones on the main board to remove.

Really appreciate your help.

Overall your calculator is correct, but it depends on how your TV in configured. Near the jungle chip there is a jumper option to connect the OSD RGB to jungle chip directly, or use the switching system. If you have those jumpers closed then I would assume that your injection point is correct, and your calculations look right. But if those jumpers are open and the signal is passing through the TEA5114A then this might complicate things a little more. Also check if R282 R284 R286 is populated. If the switch is being used then you will need to check if it has its own bias and buffer. It mostly likely does which is why they have the pull downs on R282 R284 and R286. If you can verify what open is set we might be able to figure out some next steps.

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

Jumpers are closed, TEA114A and resistors aren't populated.

I pulled the boards to clean them. I'll reinstall and check the voltages and report back. Thank you very much

[vol.2]

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

The FB pin 26 is active high. 0.9-3V. They also call the pin RGBIN elsewhere in the datasheet, so I think it's safe to assume this is RGB blanking.

RGB level is 0.7-1Vpp. The datasheet specifies that it clips the signal at 1Vpp, so it might require some circuitry to clamp hot inputs.

[Delphius]

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

The FB pin 26 is active high. 0.9-3V. They also call the pin RGBIN elsewhere in the datasheet, so I think it's safe to assume this is RGB blanking.

RGB level is 0.7-1Vpp. The datasheet specifies that it clips the signal at 1Vpp, so it might require some circuitry to clamp hot inputs.

Ok this would make sense.

My suggestion for blanking would be to tap in before the transistor, right at the base junction and match a similar circuit to how the OSD blanking is connected. Essentially changing R11 on the mux circuit to 4.7k which would probably be needed even if trying to inject right at pin 26 of the jungle. But I assume that the current draw on that FB junction with jungle pin 26 is quite high, possibly from what is connected to FB that goes down to pin 12 (SECAM module?). I think it is safer to let the transistor do the work there instead of the console.

[Delphius]

Interesting. I've seen a couple of examples in this thread of people successfully RGB modding sets with that same jungle IC. Also the schematics show 2 scart inputs, but my chassis don't have them. The service manual I'm looking at shows an option to set scart to on or off in the service menu. With that said, do I still need to supply blanking with 5V? Or setting it to on from the menu is enough?

Also could you please confirm my diagram, I'm not sure I've used Sunthar's calculator correctly to determine the resistor values and which ones on the main board to remove.

Really appreciate your help.

Overall your calculator is correct, but it depends on how your TV in configured. Near the jungle chip there is a jumper option to connect the OSD RGB to jungle chip directly, or use the switching system. If you have those jumpers closed then I would assume that your injection point is correct, and your calculations look right. But if those jumpers are open and the signal is passing through the TEA5114A then this might complicate things a little more. Also check if R282 R284 R286 is populated. If the switch is being used then you will need to check if it has its own bias and buffer. It mostly likely does which is why they have the pull downs on R282 R284 and R286. If you can verify what open is set we might be able to figure out some next steps.

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

Jumpers are closed, TEA114A and resistors aren't populated.

I pulled the boards to clean them. I'll reinstall and check the voltages and report back. Thank you very much

Sounds good. I think if you follow my advice on my previous post about the fast blanking then you should be good to go. Change R11 to 4.7k and maybe have some others on hand.

For the RGB, I think you are good with your original plan to tap into those RGB lines at that junction.

[vol.2]

Still would be an issue that the RGB inputs are clipping anything greater than 1Vpp. A lot of consoles don't respect that, and you'd get crushed blacks and whites.

If it was me, I would probably try to come up with some way to dynamically lower the input signal by creating a divider with the 14k input impedance of the RGB inputs. At the very least, I would find the hottest signal I was going to ever use on the set and put a series resistor on each channel to permanently lower it a little bit. The amount of compensation you'd have to do with bias and drive would be negligible.

[LeaveItTubeBeaver]

My next project is a Sony Kv-32s42
Documentation is plentiful for aa-2d sets but that doesn’t stop me from goofing a few things up along the way.
Everything people have posted makes sense up until I got to tapping into sync. I ended up going off a luma line from the tuner area which didn’t work. The area listed in a few guides isn’t on my specific set, so I removed my sync wire and I’m just using composite in for right now.

The image is shifted pretty far to the left, but I read that using composite instead of luma can create that image shift.

With all of that being said, is there a good place to tap into luma, or should I simply use my meter to see where the svideo luma is on the board?

If I use luma from svideo, can somebody explain how the blanking switch could be wired so that svideo can still be used? I plan on using this with an extron switch so svideo will still be used for some systems. I’m not sure if that’s relevant but I see people talk about a dummy plug.

Right now I’m using spdt switches but is there something else that I’ll need in order to have blanking and svideo/composite toggled on the same switch?

[KPackratt2k]

The Luma input is on the third pin of the S-Video connector (the top-right pin when looking at the connector on the TV's jack panel). The shield inside the connector is divided in two pieces with one piece grounded and the other piece connected to a logic signal that's held high when nothing is connected, but gets pulled down low when an S-Video cable is connected, which will connect the two shield pieces together.

One thing you can do is permanently ground the logic signal by running a jumper wire between the two shield pins, though doing this will disable the Composite video input jack on the video input lane that the S-Video input is on (Video 1 in this case). An alternative would be to use a DPDT switch to apply your blanking voltage to the jungle chip as well as ground the S-Video shield logic pin to force S-Video mode to be active while the set is in RGB mode, allowing you to use it as a sync injection point even without an S-Video cable connected.

[LeaveItTubeBeaver]

The Luma input is on the third pin of the S-Video connector (the top-right pin when looking at the connector on the TV's jack panel). The shield inside the connector is divided in two pieces with one piece grounded and the other piece connected to a logic signal that's held high when nothing is connected, but gets pulled down low when an S-Video cable is connected, which will connect the two shield pieces together.

One thing you can do is permanently ground the logic signal by running a jumper wire between the two shield pins, though doing this will disable the Composite video input jack on the video input lane that the S-Video input is on (Video 1 in this case). An alternative would be to use a DPDT switch to apply your blanking voltage to the jungle chip as well as ground the S-Video shield logic pin to force S-Video mode to be active while the set is in RGB mode, allowing you to use it as a sync injection point even without an S-Video cable connected.

Thanks! I ordered a few switches, might need help figuring out the wiring but I’m sure I can find it if I search hard enough.

Thanks again, happy new year!

[Anonygoose]

Overall your calculator is correct, but it depends on how your TV in configured. Near the jungle chip there is a jumper option to connect the OSD RGB to jungle chip directly, or use the switching system. If you have those jumpers closed then I would assume that your injection point is correct, and your calculations look right. But if those jumpers are open and the signal is passing through the TEA5114A then this might complicate things a little more. Also check if R282 R284 R286 is populated. If the switch is being used then you will need to check if it has its own bias and buffer. It mostly likely does which is why they have the pull downs on R282 R284 and R286. If you can verify what open is set we might be able to figure out some next steps.

For the FB on the OSD output, this is interesting because it connects to transistor. You need to see what the voltage is on the gate of that transistor when the OSD is ON and OFF. Also, check and see what the voltage is on the jungle chip FB pin when OSD is ON and OFF. We need to know if it is NPN or a PNP transistor to know if the gate wants 5v or a ground.

Jumpers are closed, TEA114A and resistors aren't populated.

I pulled the boards to clean them. I'll reinstall and check the voltages and report back. Thank you very much

Sounds good. I think if you follow my advice on my previous post about the fast blanking then you should be good to go. Change R11 to 4.7k and maybe have some others on hand.

For the RGB, I think you are good with your original plan to tap into those RGB lines at that junction.

Got around to installing the mod today but it's not looking good. I tapped blanking at the base of Q902 as you suggested. I get a very faint picture with retrace lines.

https://imgur.com/gallery/ybH5u3v#6cdYW3r

Thoughts?

[Delphius]

Jumpers are closed, TEA114A and resistors aren't populated.

I pulled the boards to clean them. I'll reinstall and check the voltages and report back. Thank you very much

Sounds good. I think if you follow my advice on my previous post about the fast blanking then you should be good to go. Change R11 to 4.7k and maybe have some others on hand.

For the RGB, I think you are good with your original plan to tap into those RGB lines at that junction.

Got around to installing the mod today but it's not looking good. I tapped blanking at the base of Q902 as you suggested. I get a very faint picture with retrace lines.

https://imgur.com/gallery/ybH5u3v#6cdYW3r

Thoughts?

For some reason the link you posted isn't loading right now. I will check again a bit later. Do you have a oscilloscope that you can use for testing? You are getting some image though from external RGB, it is just faint? Where you are tapping the RGB, double check there isn't any voltage bias on the line by measuring DC with a multimeter. It should be 0dc, if there is even a slight amount you might need coupling capacitors. Otherwise you will need measure what the RGB ptp voltage is if possible and you might need to adjust your resistors.

[Anonygoose]

Sounds good. I think if you follow my advice on my previous post about the fast blanking then you should be good to go. Change R11 to 4.7k and maybe have some others on hand.

For the RGB, I think you are good with your original plan to tap into those RGB lines at that junction.

Got around to installing the mod today but it's not looking good. I tapped blanking at the base of Q902 as you suggested. I get a very faint picture with retrace lines.

https://imgur.com/gallery/ybH5u3v#6cdYW3r

Thoughts?

For some reason the link you posted isn't loading right now. I will check again a bit later. Do you have a oscilloscope that you can use for testing? You are getting some image though from external RGB, it is just faint? Where you are tapping the RGB, double check there isn't any voltage bias on the line by measuring DC with a multimeter. It should be 0dc, if there is even a slight amount you might need coupling capacitors. Otherwise you will need measure what the RGB ptp voltage is if possible and you might need to adjust your resistors.

Link works for me.

Try this one: https://imgur.com/gallery/ybH5u3v

I do have a scope. I'll double check my wiring and resistors first to confirm I didn't make a mistake somewhere.

[vol.2]

I do have a scope. I'll double check my wiring and resistors first to confirm I didn't make a mistake somewhere.

Neither link works for me on a browser with or without ad blocking enabled. It tries to open and then Imgur immediately says that the links aren't available. You might have made them private. I can see the image if I look at your gallery here https://imgur.com/user/Ramiq27

I took a look at the full schematic. https://elektrotanya.com/samsung_sct55a ... ad.html#dl


Q902 does not go to the OSD blanking pin; it gets directly mixed into the luma signal and passed on to pin 27 of the jungle IC.

The schematic for you set shows that RGBS input is handled via the SCART connector and runs to pins 1, 4, 6, 8 of IC 205. That IC muxes the OSD signal and then goes to the jungle IC.

Blanking for the RGB is derived from a processed Y signal and ultimately output by IC205 as FB to pin 26. Pin 26 should be constantly between 0.9-3VDC high to blank RGB input.

Judging from the schematic, the set was supposed to have RGB from the factory in at least some configuration, but it's also an I^2C bus system, so I'm still not fully convinced that you can spoof it. If I was determined to try, I would replicate the circuit in the schematics. You would have to hook up every pin from the SCART connector to do this, even if there's other stuff besides the RGBS. There's an option for "SCART" in the service menu. That might be what tells it to look for an RGB signal at the jungle IC if you don't have a SCART jack. Then again, it might also do something weird and you might lose picture. Not sure and don't want to be held responsible for the suggestion.

You could try to spoof it and go for the high signal at pin 26 on the jungle IC (no higher than 3V). I'm not sure if it should be buffered. You would also have to use the normal RCA input for the sync.

Also, I'm assuming that your set does NOT have a SCART input, correct?

[Delphius]

I do have a scope. I'll double check my wiring and resistors first to confirm I didn't make a mistake somewhere.

Neither link works for me on a browser with or without ad blocking enabled. It tries to open and then Imgur immediately says that the links aren't available. You might have made them private. I can see the image if I look at your gallery here https://imgur.com/user/Ramiq27

I took a look at the full schematic. https://elektrotanya.com/samsung_sct55a ... ad.html#dl


Q902 does not go to the OSD blanking pin; it gets directly mixed into the luma signal and passed on to pin 27 of the jungle IC.

The schematic for you set shows that RGBS input is handled via the SCART connector and runs to pins 1, 4, 6, 8 of IC 205. That IC muxes the OSD signal and then goes to the jungle IC.

Blanking for the RGB is derived from a processed Y signal and ultimately output by IC205 as FB to pin 26. Pin 26 should be constantly between 0.9-3VDC high to blank RGB input.

Judging from the schematic, the set was supposed to have RGB from the factory in at least some configuration, but it's also an I^2C bus system, so I'm still not fully convinced that you can spoof it. If I was determined to try, I would replicate the circuit in the schematics. You would have to hook up every pin from the SCART connector to do this, even if there's other stuff besides the RGBS. There's an option for "SCART" in the service menu. That might be what tells it to look for an RGB signal at the jungle IC if you don't have a SCART jack. Then again, it might also do something weird and you might lose picture. Not sure and don't want to be held responsible for the suggestion.

You could try to spoof it and go for the high signal at pin 26 on the jungle IC (no higher than 3V). I'm not sure if it should be buffered. You would also have to use the normal RCA input for the sync.

Also, I'm assuming that your set does NOT have a SCART input, correct?

Yeah this seems more accurate. I had mistaken OSD pin 23 as OSD F/B since it is labeled OSD Blank. Looks like it is more likely OSD pin 27 instead.

Tapping to Jungle pin 26 is more appropriate for blanking probably, or on the pin side of R241 or R248 and calculate with the 1k pull down.

[Anonygoose]

I do have a scope. I'll double check my wiring and resistors first to confirm I didn't make a mistake somewhere.

Neither link works for me on a browser with or without ad blocking enabled. It tries to open and then Imgur immediately says that the links aren't available. You might have made them private. I can see the image if I look at your gallery here https://imgur.com/user/Ramiq27

I took a look at the full schematic. https://elektrotanya.com/samsung_sct55a ... ad.html#dl


Q902 does not go to the OSD blanking pin; it gets directly mixed into the luma signal and passed on to pin 27 of the jungle IC.

The schematic for you set shows that RGBS input is handled via the SCART connector and runs to pins 1, 4, 6, 8 of IC 205. That IC muxes the OSD signal and then goes to the jungle IC.

Blanking for the RGB is derived from a processed Y signal and ultimately output by IC205 as FB to pin 26. Pin 26 should be constantly between 0.9-3VDC high to blank RGB input.

Judging from the schematic, the set was supposed to have RGB from the factory in at least some configuration, but it's also an I^2C bus system, so I'm still not fully convinced that you can spoof it. If I was determined to try, I would replicate the circuit in the schematics. You would have to hook up every pin from the SCART connector to do this, even if there's other stuff besides the RGBS. There's an option for "SCART" in the service menu. That might be what tells it to look for an RGB signal at the jungle IC if you don't have a SCART jack. Then again, it might also do something weird and you might lose picture. Not sure and don't want to be held responsible for the suggestion.

You could try to spoof it and go for the high signal at pin 26 on the jungle IC (no higher than 3V). I'm not sure if it should be buffered. You would also have to use the normal RCA input for the sync.

Also, I'm assuming that your set does NOT have a SCART input, correct?

I have some cold joints somewhere in the video process board, I put everything back to stock and was still getting a faint pic with retrace lines. Poking at the board I managed to get display back, so it was not related to the mod.

I put the mod back in as per Delphius' instructions and got composite over scart, so RGB isn't blanking.

Should I try tapping blanking directly to pin 26 of the jungle IC? I am using a Sunthar mux board by the way. Do I still need the 4.7K resistor at R11?

[Delphius]

I do have a scope. I'll double check my wiring and resistors first to confirm I didn't make a mistake somewhere.

Neither link works for me on a browser with or without ad blocking enabled. It tries to open and then Imgur immediately says that the links aren't available. You might have made them private. I can see the image if I look at your gallery here https://imgur.com/user/Ramiq27

I took a look at the full schematic. https://elektrotanya.com/samsung_sct55a ... ad.html#dl


Q902 does not go to the OSD blanking pin; it gets directly mixed into the luma signal and passed on to pin 27 of the jungle IC.

The schematic for you set shows that RGBS input is handled via the SCART connector and runs to pins 1, 4, 6, 8 of IC 205. That IC muxes the OSD signal and then goes to the jungle IC.

Blanking for the RGB is derived from a processed Y signal and ultimately output by IC205 as FB to pin 26. Pin 26 should be constantly between 0.9-3VDC high to blank RGB input.

Judging from the schematic, the set was supposed to have RGB from the factory in at least some configuration, but it's also an I^2C bus system, so I'm still not fully convinced that you can spoof it. If I was determined to try, I would replicate the circuit in the schematics. You would have to hook up every pin from the SCART connector to do this, even if there's other stuff besides the RGBS. There's an option for "SCART" in the service menu. That might be what tells it to look for an RGB signal at the jungle IC if you don't have a SCART jack. Then again, it might also do something weird and you might lose picture. Not sure and don't want to be held responsible for the suggestion.

You could try to spoof it and go for the high signal at pin 26 on the jungle IC (no higher than 3V). I'm not sure if it should be buffered. You would also have to use the normal RCA input for the sync.

Also, I'm assuming that your set does NOT have a SCART input, correct?

I have some cold joints somewhere in the video process board, I put everything back to stock and was still getting a faint pic with retrace lines. Poking at the board I managed to get display back, so it was not related to the mod.

I put the mod back in as per Delphius' instructions and got composite over scart, so RGB isn't blanking.

Should I try tapping blanking directly to pin 26 of the jungle IC? I am using a Sunthar mux board by the way. Do I still need the 4.7K resistor at R11?

I think you can try to do fast blanking at pin 26 on the jungle, and definitely keep the 4.7k resistor at R11. The math / divider should be the same because you also have a 1k pull down on jungle pin 26. You can solder to the jumper on that line, to the pin directly, or the pin side of R241. Whichever is easiest.

[Anonygoose]

Blanking directly to pin 26 still no RGB.

I wired 3V through a switch and still no RGB. Even after switching scart to on in service menu. Measuring voltage at pin 26 shows -3.5V when the switch is set to on. Flipping the switch from on to off I can see a slight change in sharpness, which is weird, but dot crawl all over the place and Chroma still works. Also when switch is to on, OSD disappears.

Edit: My voltage divider for the 5V point I am using may be wrong. I am tired for today. I'll double check tomorrow and report back.

Circuit I wired up is 5V to 3.3k and 6.8K in series to the switch.

[Delphius]

Blanking directly to pin 26 still no RGB.

I wired 3V through a switch and still no RGB. Even after switching scart to on in service menu. Measuring voltage at pin 26 shows -3.5V when the switch is set to on. Flipping the switch from on to off I can see a slight change in sharpness, which is weird, but dot crawl all over the place and Chroma still works. Also when switch is to on, OSD disappears.

Edit: My voltage divider for the 5V point I am using may be wrong. I am tired for today. I'll double check tomorrow and report back.

Circuit I wired up is 5V to 3.3k and 6.8K in series to the switch.

Looking at the full schematic again, I think there is some rather complex switching going on with these RGB lines that needs to be considered. Is IC205 populated at all on this board? If not we might need to be looking more at injecting around IC206 and IC207. One of those switches the PIP and the other the OSD. If IC205 is populated, then we might be able to remove the jumpers, and the resistor just below it and inject RGB and blanking into those lines there like it was intended for external RGB. Otherwise, we might have to look at the inputs of IC206 and IC207 and triggering the switch there.

It seems like you are triggering the jungle fast blanking, but there are other signals trying to compete or are not switching.

[Anonygoose]

Blanking directly to pin 26 still no RGB.

I wired 3V through a switch and still no RGB. Even after switching scart to on in service menu. Measuring voltage at pin 26 shows -3.5V when the switch is set to on. Flipping the switch from on to off I can see a slight change in sharpness, which is weird, but dot crawl all over the place and Chroma still works. Also when switch is to on, OSD disappears.

Edit: My voltage divider for the 5V point I am using may be wrong. I am tired for today. I'll double check tomorrow and report back.

Circuit I wired up is 5V to 3.3k and 6.8K in series to the switch.

Looking at the full schematic again, I think there is some rather complex switching going on with these RGB lines that needs to be considered. Is IC205 populated at all on this board? If not we might need to be looking more at injecting around IC206 and IC207. One of those switches the PIP and the other the OSD. If IC205 is populated, then we might be able to remove the jumpers, and the resistor just below it and inject RGB and blanking into those lines there like it was intended for external RGB. Otherwise, we might have to look at the inputs of IC206 and IC207 and triggering the switch there.

It seems like you are triggering the jungle fast blanking, but there are other signals trying to compete or are not switching.

IC205 isn't populated.

PIP is populated, anything we can do there?

[Delphius]

Blanking directly to pin 26 still no RGB.

I wired 3V through a switch and still no RGB. Even after switching scart to on in service menu. Measuring voltage at pin 26 shows -3.5V when the switch is set to on. Flipping the switch from on to off I can see a slight change in sharpness, which is weird, but dot crawl all over the place and Chroma still works. Also when switch is to on, OSD disappears.

Edit: My voltage divider for the 5V point I am using may be wrong. I am tired for today. I'll double check tomorrow and report back.

Circuit I wired up is 5V to 3.3k and 6.8K in series to the switch.

Looking at the full schematic again, I think there is some rather complex switching going on with these RGB lines that needs to be considered. Is IC205 populated at all on this board? If not we might need to be looking more at injecting around IC206 and IC207. One of those switches the PIP and the other the OSD. If IC205 is populated, then we might be able to remove the jumpers, and the resistor just below it and inject RGB and blanking into those lines there like it was intended for external RGB. Otherwise, we might have to look at the inputs of IC206 and IC207 and triggering the switch there.

It seems like you are triggering the jungle fast blanking, but there are other signals trying to compete or are not switching.

IC205 isn't populated.

PIP is populated, anything we can do there?

I think your next best try would be to tap into the inputs of IC206 where it is labeled OSD-R G B, then try tapping in the line label OSD - F/B just below that or pin 10, 12 or 15 on the IC206 IC. You have a slightly higher pulldown resistor on that line with 1.8k instead of 1k. This might be good if you are trying to use 3v into your FB, typically you will use 5v I think. However, the coupling capacitors on the inputs of IC206 indicate to me that there is going to be DC bias on those inputs so you will probably need to add 1uf coupler caps (ceramic should work) to your mux mod as well.

Shoot it might even be worth swapping the PIP TEA5114A with the IC205 and see if you can utilize that external AV switch if it can function fine without PIP.

[Anonygoose]

Looking at the full schematic again, I think there is some rather complex switching going on with these RGB lines that needs to be considered. Is IC205 populated at all on this board? If not we might need to be looking more at injecting around IC206 and IC207. One of those switches the PIP and the other the OSD. If IC205 is populated, then we might be able to remove the jumpers, and the resistor just below it and inject RGB and blanking into those lines there like it was intended for external RGB. Otherwise, we might have to look at the inputs of IC206 and IC207 and triggering the switch there.

It seems like you are triggering the jungle fast blanking, but there are other signals trying to compete or are not switching.

IC205 isn't populated.

PIP is populated, anything we can do there?

I think your next best try would be to tap into the inputs of IC206 where it is labeled OSD-R G B, then try tapping in the line label OSD - F/B just below that or pin 10, 12 or 15 on the IC206 IC. You have a slightly higher pulldown resistor on that line with 1.8k instead of 1k. This might be good if you are trying to use 3v into your FB, typically you will use 5v I think. However, the coupling capacitors on the inputs of IC206 indicate to me that there is going to be DC bias on those inputs so you will probably need to add 1uf coupler caps (ceramic should work) to your mux mod as well.

Shoot it might even be worth swapping the PIP TEA5114A with the IC205 and see if you can utilize that external AV switch if it can function fine without PIP.

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?

[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.

[digitron]

Curious if any of you experienced a black screen when selecting your antenna/RF tuner input after modding your CRT? Can still cycle through channels and sound works, but instead of the normal white/black static on the screen, its just black (video from a RF modulator connected to antenna won't display but I can hear sound). I have a switch to disable the RGB mod (and composite works), I'm wondering if it's the tuner itself.

The menu display overlay becomes garbled/distorted when selecting the antenna input as well, it looks fine when using the video input and RGB input.

[vol.2]

Curious if any of you experienced a black screen when selecting your antenna/RF tuner input after modding your CRT? Can still cycle through channels and sound works, but instead of the normal white/black static on the screen, its just black (video from a RF modulator connected to antenna won't display but I can hear sound). I have a switch to disable the RGB mod (and composite works), I'm wondering if it's the tuner itself.

The menu display overlay becomes garbled/distorted when selecting the antenna input as well, it looks fine when using the video input and RGB input.

This would depend on how you did the mod and the exact layout of your set.

If you bypassed the video IFs in order to inject composite further down the chain, then you interrupted the signal chain through the RF of your set. You would need to post a picture of your schematic and trace all the changes you made on top of it with red lines, along with a clear explanation of your changes.

[digitron]

Curious if any of you experienced a black screen when selecting your antenna/RF tuner input after modding your CRT? Can still cycle through channels and sound works, but instead of the normal white/black static on the screen, its just black (video from a RF modulator connected to antenna won't display but I can hear sound). I have a switch to disable the RGB mod (and composite works), I'm wondering if it's the tuner itself.

The menu display overlay becomes garbled/distorted when selecting the antenna input as well, it looks fine when using the video input and RGB input.

This would depend on how you did the mod and the exact layout of your set.

If you bypassed the video IFs in order to inject composite further down the chain, then you interrupted the signal chain through the RF of your set. You would need to post a picture of your schematic and trace all the changes you made on top of it with red lines, along with a clear explanation of your changes.

Thank you for the reply, that makes sense. Here's my original post - viewtopic.php?p=1488200#p1488200

Followed Marks schematic - https://klovimg.com/images/2018/07/17/O ... uit-v2.png

BLAH! Forgot I ran a separate switch for sync on luma, that was it. I'm dumb!

[vol.2]

BLAH! Forgot I ran a separate switch for sync on luma, that was it. I'm dumb!

Lol. Sometimes it just takes reviewing the footage.