TV RGB mod thread

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krimstah
Posts: 13
Joined: Fri Dec 28, 2018 8:51 am

Re: TV RGB mod thread

Post by krimstah »

Hi All,

I am having an incredibly difficult time injecting rgb into a teletext header in my Mitsubishi crt. I have documented the whole chain in the following PDF for someone who knows what they are doing with resister values.

I have identified the Jungle Chip and corresponding RGB pins and blanking pin, The TV blanks no problem , just injecting RGB seems to be a problem as nothing shows up on screen.

Jungle Chip: Toshiba - TA8719AN

Documentation I have created:

https://www.docdroid.net/13TV4oA/mitsub ... pdf#page=4

Pictures of CRT:

https://imgur.com/a/VlPRvIE

Video of CRT Blanking:

https://imgur.com/a/sSLSq83

If anyone could please help me that would be appreciated. This is a really nice set that I would like to turn into my daily driver.

Thanks
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.

Here is the Jungle Chip data sheet: https://pdf1.alldatasheet.com/datasheet ... 465AS.html

Here is the Service Manual for the TV: https://manualmachine.com/sony/kv27v10/ ... ce-manual/

Thanks to anyone that would be willing to help me!
Derf
Posts: 26
Joined: Sun Sep 13, 2020 12:15 am

Re: TV RGB mod thread

Post by Derf »

Pulled it off, info here: https://consolemods.org/wiki/CRT:C-13011
RVA818XLAY wrote:
Derf wrote: Looks the same if I unplug the sync cable as well or plug sync into the composite RCA jack.
If it looks the same then the TV isn't receiving the sync signal, right? Can you measure and check that a signal is actually going down the sync line?
Unfortunately, I don't have the ability to measure that.

After talking with others though, it was pointed out that it's likely backfeeding signals / not properly muxing and I need to do some resistor math specific for the JVC C-13011 which I don't know how to do. Someone sent me a chassis schematic for it.

Jungle IC (Toshiba TA1242N) side:
Image

Other side:
Image

I also traced some of it out on the actual board to verify that it matched. The only thing that didn't match was the 1.5k resistors were actually 1k.
Image
Last edited by Derf on Thu Nov 24, 2022 6:37 am, edited 1 time in total.
rideordie71
Posts: 5
Joined: Mon Apr 25, 2022 11:45 am

Re: TV RGB mod thread

Post by rideordie71 »

SweetStrat57 wrote:Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.

Here is the Jungle Chip data sheet: https://pdf1.alldatasheet.com/datasheet ... 465AS.html

Here is the Service Manual for the TV: https://manualmachine.com/sony/kv27v10/ ... ce-manual/

Thanks to anyone that would be willing to help me!

All free service manuals that I have come across during a good 10 minute search produce the same PDF with the wiring schematic missing from it (document pages 55 - 80) for the boards that possibly have the jungle chip (CXA1465AS) schematic for your set.

Perhaps look at this:
https://crtdatabase.com/crts/sony/sony- ... is-rgb-mod
It has the same jungle chip. You'll just have to do some sleuthing to determine if you can just as easily inject your RGB into the other set of RGB inputs on CXA1465AS.
Pencilman
Posts: 7
Joined: Thu Aug 18, 2022 7:24 pm

Re: TV RGB mod thread

Post by Pencilman »

Hi,

I've gotten my hands on a Sanyo crt. Can anyone tell from this schemstic if it's a hot chasis? It looks like a fairly old tv but I have no clue what to lool for when talking about hot chassis.

https://elektrotanya.com/sanyo_a1b14_ch ... nload.html

Thank you :)
krimstah
Posts: 13
Joined: Fri Dec 28, 2018 8:51 am

Re: TV RGB mod thread

Post by krimstah »

krimstah wrote:Hi All,

I am having an incredibly difficult time injecting rgb into a teletext header in my Mitsubishi crt. I have documented the whole chain in the following PDF for someone who knows what they are doing with resister values.

I have identified the Jungle Chip and corresponding RGB pins and blanking pin, The TV blanks no problem , just injecting RGB seems to be a problem as nothing shows up on screen.

Jungle Chip: Toshiba - TA8719AN

Documentation I have created:

https://www.docdroid.net/13TV4oA/mitsub ... pdf#page=4

Pictures of CRT:

https://imgur.com/a/VlPRvIE

Video of CRT Blanking:

https://imgur.com/a/sSLSq83

If anyone could please help me that would be appreciated. This is a really nice set that I would like to turn into my daily driver.

Thanks
I figured it out needed a voltage divider on the banking pin to activate rgb , can directly feed rgb lines into the teletext header without resistors
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

SweetStrat57 wrote:Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.
This isn't too different from one of the sets that I've modded previously. After taking a look at the service manual, I think I can help you with it.

- Remove C315, C316, C317, and D004.
- Inject 75 ohm terminated (resistors from signals to ground) RGB with 0.1 uF capacitors into pins 16, 17, and 18 of IC301.
- Use a DPDT switch to handle blanking and enabling the S-Video input for sync injection.
- For blanking, take 9V and create a voltage divider with two 1k ohm resistors (the first resistor inline on the 9V rail and the second from the first resistor to ground with the non-grounded side running to your injection point) to lower the voltage to 4.5V, run this into the lower center pin of the switch and run the lower right pin into pin 15 of IC301.
- For S-Video input activation, run ground into the upper center pin of your switch and run the sensing pin (the upper center pin of the S-Video connector coming from a part of the shield) into the upper right pin of the switch.

Inject Sync into S-Video Luma (pin 3) and Audio into the signal pads for the Video 1 audio jacks. You may have to cut a trace that runs the audio jacks together for mono combination to preserve stereo audio if you're wiring a SCART connector.
Last edited by KPackratt2k on Wed Nov 16, 2022 11:58 pm, edited 1 time in total.
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

KPackratt2k wrote:
SweetStrat57 wrote:Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.
This isn't too different from one of the sets that I've modded previously. After taking a look at the service manual, I think I can help you with it.

- Remove C315, C316, C317, and D004.
- Inject 75 ohm terminated (resistors from signals to ground) RGB with 0.1 uF capacitors into pins 16, 17, and 18 of IC301.
- Use a DPDT switch to handle blanking and enabling the S-Video input for sync injection.
- For blanking, take 9V and create a voltage divider with two 1k ohm resistors (the first resistor inline on the 9V rail and the second from the first resistor to ground with the non-grounded side running to your injection point) to lower the voltage to 4.5V, run this into the lower center pin of the switch and run the lower right pin into pin 15 of IC301.
- For S-Video input activation, run ground into the upper center pin of your switch and run the sensing pin (the upper center pin of the S-Video connector coming from a part of the shield) into the upper right pin.

Inject Sync into S-Video Luma (pin 3) and Audio into the signal pads for the Video 1 audio jacks. You may have to cut a trace that runs the audio jacks together for mono combination to preserve stereo audio if you're wiring a SCART connector.
Thank you for your help, KPackratt2k!

I have a question about creating the blanking switch. I drew what I think you are describing. Can you verify this or tell me what I need to change?

Image
KPackratt2k
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Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

It looks fine to me. Measure your voltage coming into the switch with a multimeter to verify the voltage divider is working.
maffatil
Posts: 13
Joined: Sun May 29, 2022 5:28 pm

Re: TV RGB mod thread

Post by maffatil »

After a month of saying I'm going to do it, I tested the chroma chip on my Toshiba 32df46 (on page 156 of this post) to see if it was analog or not. When I sent 5v to the blanking pin I surprisingly got a black screen, which according to Andy King's site, that means the osd is analog. Just for the hell of it, I wired up everything on a scart socket, lifted a few jumpers, then soldered everything in place. I got very incorrectly colored image, but I got one!
Spoiler
Image
My question is now, where do I go from here? As I posted ~a month ago, there are not capacitors on the osd lines (though I believe there are grounding resistors) and everything is smd because this is a fairly late crt. I don't quite know where to go with diodes and everything else as shown on the guide as I have quite a few resistors and the transistors on the osd and blanking lines so I have no clue which ones to remove and which ones to calculate diode and resistor values from.
Here's my marked up picture of the board again in case anyone is curious enough to check it out.
Spoiler
Image
P.S. I'm guessing what's going on with this thing is that the osd signals from the micon chip are digital (it has 0v osd outputs), but through the magic of transistors that I don't fully understand, it converts it to analog by the time it gets to the chroma (which has 3.3v inputs).
Very interestingly, the static won't show up on the tv without the blanking pin connected. I'd say that's because it's actually part of the osd, but I don't think I'm qualified enough to make that call (aka, I'm very likely VERY wrong on that one...)
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matt
Posts: 567
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Re: TV RGB mod thread

Post by matt »

maffatil wrote:After a month of saying I'm going to do it, I tested the chroma chip on my Toshiba 32df46 (on page 156 of this post) to see if it was analog or not. When I sent 5v to the blanking pin I surprisingly got a black screen, which according to Andy King's site, that means the osd is analog. Just for the hell of it, I wired up everything on a scart socket, lifted a few jumpers, then soldered everything in place. I got very incorrectly colored image, but I got one!
A black screen with blanking doesn't mean that it's analog. It could still be digital. A white screen with blanking enabled definitely means it's not a standard analog signal, though.

The screen shot you posted looks like what you get with an analog signal on a digital input. I think it's safe to say that this mod won't work.
maffatil
Posts: 13
Joined: Sun May 29, 2022 5:28 pm

Re: TV RGB mod thread

Post by maffatil »

matt wrote:The screen shot you posted looks like what you get with an analog signal on a digital input. I think it's safe to say that this mod won't work.
Yeah some part of me knew that was really the case. I think it actually scales 240p anyway. I'll try removing the grounding resistors at some point just to see what happens, but in the end if it doesn't work, it doesn't work. Can't win with every garbage tv lol!
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

KPackratt2k wrote:
SweetStrat57 wrote:Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.
This isn't too different from one of the sets that I've modded previously. After taking a look at the service manual, I think I can help you with it.

- Remove C315, C316, C317, and D004.
- Inject 75 ohm terminated (resistors from signals to ground) RGB with 0.1 uF capacitors into pins 16, 17, and 18 of IC301.
- Use a DPDT switch to handle blanking and enabling the S-Video input for sync injection.
- For blanking, take 9V and create a voltage divider with two 1k ohm resistors (the first resistor inline on the 9V rail and the second from the first resistor to ground with the non-grounded side running to your injection point) to lower the voltage to 4.5V, run this into the lower center pin of the switch and run the lower right pin into pin 15 of IC301.
- For S-Video input activation, run ground into the upper center pin of your switch and run the sensing pin (the upper center pin of the S-Video connector coming from a part of the shield) into the upper right pin.

Inject Sync into S-Video Luma (pin 3) and Audio into the signal pads for the Video 1 audio jacks. You may have to cut a trace that runs the audio jacks together for mono combination to preserve stereo audio if you're wiring a SCART connector.
I have another question about SCART, sync, and inputs.

I am using a SCART jack for this mod. Can I tie that in to "Input 3" of the TV which uses Yellow, White, Red RCA inputs instead of the S-Video input? I would like to be able to use the S-Video on "Input 1" for my Dreamcast.

Also, how do I connect the DPDT switch to the SCART jack? I'm thinking I run the center pin of the yellow video input to SCART pin 20 and the ground from the yellow video input to SCART pin 17? According to your instructions above, I'll be running the top center and top right pins of the DPDT switch to the video ground and input respectively. Do I connect the SCART pins and DPDT pins both to the video input?

Also, for audio it does appear that stereo inputs indeed merge to mono. I'm hesitant to start cutting traces on the back of the input board in fear that I will really screw something up. Are there detailed instructions available somewhere for this that I could follow? If not, I may just leave it how it is.
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Osirus
Posts: 214
Joined: Tue Jun 16, 2020 8:51 pm

Re: TV RGB mod thread

Post by Osirus »

SweetStrat57 wrote: I am using a SCART jack for this mod. Can I tie that in to "Input 3" of the TV which uses Yellow, White, Red RCA inputs instead of the S-Video input? I would like to be able to use the S-Video on "Input 1" for my Dreamcast.
You could, but there's usually more of a shift to the right in the image if you use the composite input for sync. The method you quoted will not render your existing S-video inoperable. You can use injected RGB on your S-video input and still use normal S-video when the toggle switch is off.
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

KPackratt2k wrote:
SweetStrat57 wrote:Hello all. The members of this board have helped me to successfully RGB mux mod a Philips TV in the past. I just acquired a Sony KV-27V10 with a AA-1 chassis that I would like to RGB mod. I will try to provide all of the resources I have found to help with the mod.
This isn't too different from one of the sets that I've modded previously. After taking a look at the service manual, I think I can help you with it.

- Remove C315, C316, C317, and D004.
- Inject 75 ohm terminated (resistors from signals to ground) RGB with 0.1 uF capacitors into pins 16, 17, and 18 of IC301.
- Use a DPDT switch to handle blanking and enabling the S-Video input for sync injection.
- For blanking, take 9V and create a voltage divider with two 1k ohm resistors (the first resistor inline on the 9V rail and the second from the first resistor to ground with the non-grounded side running to your injection point) to lower the voltage to 4.5V, run this into the lower center pin of the switch and run the lower right pin into pin 15 of IC301.
- For S-Video input activation, run ground into the upper center pin of your switch and run the sensing pin (the upper center pin of the S-Video connector coming from a part of the shield) into the upper right pin.

Inject Sync into S-Video Luma (pin 3) and Audio into the signal pads for the Video 1 audio jacks. You may have to cut a trace that runs the audio jacks together for mono combination to preserve stereo audio if you're wiring a SCART connector.
I'm still confused about running S-video's Luma and Ground to the SCART jack. I have S video luma and S video ground running to the DPDT Switch. What do I need to do to hook the S-Video luma and Ground to the SCART?
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

SweetStrat57 wrote:I'm still confused about running S-video's Luma and Ground to the SCART jack. I have S video luma and S video ground running to the DPDT Switch. What do I need to do to hook the S-Video luma and Ground to the SCART?
The sensing pin goes to the switch, not Luma. Luma goes to pin 20 of the SCART connector and will act as the sync input for RGB. It's best to ground every ground pin of the SCART connector (Pins 4, 5, 9, 13, 17, 18, and 21) as some cheaper cables will only use one of these pins. You can tie all of your grounds together by carefully soldering a solid core wire onto all of those ground pins on your SCART connector, then run one of those pins to the nearest ground on the chassis.
SweetStrat57
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Re: TV RGB mod thread

Post by SweetStrat57 »

Well, looks like I screwed up the mod. Here is the image I'm getting on every input including channels. At first I was getting no image except the input identification. This image is after I turn the flyback (neckboard on this tv) brightness all the way up. Can anyone tell me what's going on here and help?

Image
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Osirus
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Joined: Tue Jun 16, 2020 8:51 pm

Re: TV RGB mod thread

Post by Osirus »

SweetStrat57 wrote:Well, looks like I screwed up the mod. Here is the image I'm getting on every input including channels.
Always, or only when you have your RGB switch enabled?
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

Osirus wrote:
SweetStrat57 wrote:Well, looks like I screwed up the mod. Here is the image I'm getting on every input including channels.
Always, or only when you have your RGB switch enabled?
Always
User avatar
Osirus
Posts: 214
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Re: TV RGB mod thread

Post by Osirus »

SweetStrat57 wrote:
Osirus wrote:
SweetStrat57 wrote:Well, looks like I screwed up the mod. Here is the image I'm getting on every input including channels.
Always, or only when you have your RGB switch enabled?
Always
Gotta start with the obvious stuff. Did you mistakenly inject in the the jungle RGB outputs instead of inputs?
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

Osirus wrote:Gotta start with the obvious stuff. Did you mistakenly inject in the the jungle RGB outputs instead of inputs?
Just verified they are going to the correct pins on the jungle, pins 16, 17, 18.
DatPhosphorGlow
Posts: 85
Joined: Tue Apr 07, 2015 7:23 am

Re: TV RGB mod thread

Post by DatPhosphorGlow »

I know this is an RGB mod thread but can someone help me figure out if my JVC AV-20CM4 can be modded for S-Video? A few have already mentioned it probably can't be modded for RGB.

Here is a link to a PDF service manual with the board schematics. https://pdfslide.net/documents/av20bm4- ... tml?page=1

I absolutely love this thing but really need to get at least get S-Video out of it for it to be a keeper. It has a high resolution tube and the stereo sound coming out of it is AMAZING. The tube is like new and I even scored a new old stock remote off ebay for it. If I can get S-Video out of this TV it would be my end game CRT. I've done all the RGB this and PVM/BVM that, I just really like this thing.

I only play PSX, and the composite video output just isn't cutting it for the graphics the console is capable of outputting.

I'm quite handy with an iron, pcbs, and components, but when it comes to technicalities of electrical engineering I'm pretty lost. Absolutely no problem drilling a hole in the back for an S-Video port.

Have an iron, multimeter, power supply and all that good stuff so can report back as instructed for error diagnosis. No oscilloscope though.

Any help/advice greatly appreciated!

Blurry cell phone pictures for your viewing pleasure (composite video):

Image

Image

Image
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

To catch everyone up on my mod who may be able to help, here's the story so far. I am really hoping someone can help me with my mod-gone-wrong.

First of all, my TV is a Sony KV-27V10 with a AA-1 chassis.

Here is the Jungle Chip data sheet: https://pdf1.alldatasheet.com/datasheet ... 465AS.html

Here is the Service Manual for the TV: https://manualmachine.com/sony/kv27v10/ ... ce-manual/

I followed the steps below by KPackratt2k:

- Remove C315, C316, C317, and D004.
- Inject 75 ohm terminated (resistors from signals to ground) RGB with 0.1 uF capacitors into pins 16, 17, and 18 of IC301.
- Use a DPDT switch to handle blanking and enabling the S-Video input for sync injection.
- For blanking, take 9V and create a voltage divider with two 1k ohm resistors (the first resistor inline on the 9V rail and the second from the first resistor to ground with the non-grounded side running to your injection point) to lower the voltage to 4.5V, run this into the lower center pin of the switch and run the lower right pin into pin 15 of IC301.
- For S-Video input activation, run ground into the upper center pin of your switch and run the sensing pin (the upper center pin of the S-Video connector coming from a part of the shield) into the upper right pin.

Inject Sync into S-Video Luma (pin 3) and Audio into the signal pads for the Video 1 audio jacks. You may have to cut a trace that runs the audio jacks together for mono combination to preserve stereo audio if you're wiring a SCART connector.


This image is the post-mod result I'm getting on every input including channels. At first I was getting no image except the input identification. This image is after I turn the flyback (neckboard on this tv) screen all the way up. I get this same image no matter what the DPDT switch is set to.

Image

Can you provide any assistance to help correct this mod? Do you see any steps that I'm missing from the directions I followed above?

Thank you!
KPackratt2k
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Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

Have you checked to find the non-grounded pin of the S-Video shield? You want to ground the side that isn't grounded. I assumed this was the upper-center pin since it was on every Sony TV that I've modded, but there's a chance that it's actually the lower-center pin. Measure continuity to ground with the multimeter (with the switch disconnected) to find out for sure. Then again if this was the case, it would likely only act weird when the switch is turned on, so probably not.

Check your soldering for shorts, it's possible that you've made a mistake when soldering and bridged to a pin that shouldn't be bridged.

Make sure you're not sending the grounded sides of the 75 ohm resistors to the RGB input of the jungle.
SweetStrat57
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Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

KPackratt2k wrote:Have you checked to find the non-grounded pin of the S-Video shield? You want to ground the side that isn't grounded. I assumed this was the upper-center pin since it was on every Sony TV that I've modded, but there's a chance that it's actually the lower-center pin. Measure continuity to ground with the multimeter (with the switch disconnected) to find out for sure. Then again if this was the case, it would likely only act weird when the switch is turned on, so probably not.

Check your soldering for shorts, it's possible that you've made a mistake when soldering and bridged to a pin that shouldn't be bridged.

Make sure you're not sending the grounded sides of the 75 ohm resistors to the RGB input of the jungle.

You helped me solve my problem! I desoldered everything I previously did. I then checked the pins on the jungle chip and Ys and R were bridged. I fixed that and soldered everything back up, a bit neater this time, though. Now I'm getting signal through SCART and S-video. So, I thank you again for your help!

I am noticing another issue that I'm guessing is interference, but hopefully you can help me with this, too. Can you see the slightly diagonal lines in the images below? They roll upwards, downwards, pause, then repeat.

Image
Image
Image

What do you think this is and do you have any suggestions on how to fix the problem?

Thanks again for your help!
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

Make sure your wires are away from the high voltage (flyback) and power supply areas. If that doesn't fix it, your best bet would be to use shielded wire (for example: wires from a spare high-quality VGA cable). What is the gauge of the wires you're using?
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

KPackratt2k wrote:Make sure your wires are away from the high voltage (flyback) and power supply areas. If that doesn't fix it, your best bet would be to use shielded wire (for example: wires from a spare high-quality VGA cable). What is the gauge of the wires you're using?
I initially used 22 AWG which produced the SEGA screens above. I don't think I can avoid high voltage areas as my SCART input is right above where the power cable attaches to the chassis. I spent some time this afternoon destroying a VGA cable to use, but I was still getting those diagonal lines. I made sure to ground the shielding to the chassis as well. But I had so much trouble with the thin wiring in the VGA cable that easily snapped off my SCART pins. I may go back to the unshielded 22 AWG wire as those are much more resilient.

Anything else I can try? I hate to have spent so much time and energy on this mod to end up with those lines in my image.
SweetStrat57
Posts: 13
Joined: Sun Sep 25, 2022 3:15 am

Re: TV RGB mod thread

Post by SweetStrat57 »

I want to thank KPackratt2k and everyone else who helped me with my mod. In my last post I indicated that I was having interference issues. I've use a chopped up VGA cable in the past since those are shielded, but I've always hated how frail the tiny gauge of wire that are in those. I then came across 18/4 shielded security cable at Home Depot. It has 4 leads and a ground wire which is perfect for RGB, Sync, and Ground. The added benefit of using the ground lead in the cable is that it also provided shielding. http://www.homedepot.com/p/Southwire-50 ... /202316270 You can purchase it by the foot in store. I ended up getting 6' for less than $5, which is well more than what I needed. I don't know if this kind of cable has been recommended on here before, but I found it much easier to work with than a VGA cable. I hope this info helps others.

Thanks again everyone!
labrat
Posts: 10
Joined: Mon Oct 05, 2020 10:08 pm

Re: TV RGB mod thread

Post by labrat »

Hello Video Modders.. I need some help with the latest 19" that I'm trying to save from the recycle.
Model: Zenith B19A21D Age: 1999
Chassis: CN-220A

I was unable to find a service manual for this particular television, but there is a DAEWOO manual with the same CN-220A chassis.
Daewoo; DTQ20J5FC; Chassis:CN-220A (PDF readily available through simple google search).

Note: This model was restricted to RF only, so I though the first step would be to try and get a composite video input operational, as I would need to get the H/V Sync coming in through there eventually.
Looking at the schematic in the Daewoo manual, and comparing to the chassis itself, I can see that the microcontroller is a zenith branded version of the ZE863232 (can't find any documentation on that one) which I think is likely a variation of the the DW863232 detailed in the schematic.
  • Step 1: Noted that the "Option" pin 0 is used to denote an RF ONLY vs LINE capable device. So I moved the pullup to a pull down, and on next restart, the TV now provides the ability to "Select AUX", display OSD "AUX" and blank screen. Not surprising it's blank as there is no External Video being fed to pin 42 of the Jungle. (Labelled "Ex. Video Input (Y IN)")
  • Step 2: Connect incoming composite video feed (from an Arduino generating simple black and white composite) to a 100/75 voltage divider bridge. (copied this part from a different but similar schematic (and this may be where I'm going wrong). Result: Still a black screen with no video.
  • Step 3: (many step 3's as nothing has resolved this yet..) Including strapping pin 36 of the micro to gnd (Power On mode (Gnd = LINE)), as well as hooking up an I2C sniffer to watch for the "Video SW:" setting(s), as I believe these would be needed in order to direct the jungle to switch inputs to the external signal. I have attempted forcing the Video SW: to 1 (ext video) 1/10 of a millisecond after any write to that register to set it to (int video). But the results are the same ... black screen .. with "AUX" OSD display.

Update: Sniffing I2C bus before/after selecting AUX: reveals that the following two i2c changes: Register 0x14, bit 7 (0x80) (Video SW:1), and Register 0x1E, bit 0 (0x01) (AF.AGC = AGC Defeat)

Back to the schematics.. and another chassis that appears to be using the same jungle chip, has a more complicated input circuit.
Image

Combined with reading the Jungle Chip (LA76814) document : Which says VIN1DC should be min/max 2.2 to 2.8 volts

Am I reading this correctly? (Software developer trying to make sense of the hardware specs : 8) )
Is the signal at pin 42 actually level shifted from the typical 0.7v ?

If not .. does anyone have some additional pointers on things to try?

Thank you for any guidance. :)

Update: Reading the forum for other instances of the LA76814 and I'm convinced that it should be receiving a normal composite input (714mV)
Currently only seeing a black screen. The only thing of note is that when I hook up the external video, the "AUX" text develops a periodic jitter that is not present if there is no video input.

Any ideas on what to try next? Behaviour- select AUX.. get black screen with "AUX" green text. No sign of the incoming video.
Link040188
Posts: 3
Joined: Sat Nov 26, 2022 9:04 pm

Re: TV RGB mod thread

Post by Link040188 »

Hello RGB experts I'm in the planning stage of rgb modding my Sylvania 6513DA but need a little guidance.

So I'm unable to find a schematic of my tv but I the board is well marked and I found the data sheets for both the osd micon and the video processor.

this is the osd micon https://pdf1.alldatasheet.com/datasheet ... 272M8.html

this is the video processor https://pdf1.alldatasheet.com/datasheet ... 03CFP.html

first I can see that the video processor is capable of receiving both analog and digital rgb for osd. I did send 5v on the blanking circuit and any osd(example the current input selection) disappears and the screen is solid black. but I read earlier in this thread that that is not a definitive test. so what else can I do to determine if this is a viable tv for a osd mux mod.

second I can outline the stock circuit. the rgb signal lines have an inline resistor a grounded resistor and a grounded capacitor. the inline resistor is a 3.3kohm and the grounded resistor is 820ohm. there is no inline capacitor. the blanking line is similar with one inline resistor and then a grounded resistor and a grounded capacitor. the inline resistor on the blanking line is 820ohm and the grounded resistor is 470ohm.

based on the schematic and resistor table by MarkOZLAD my plan was to inject the rgb with a 470ohm resistor on each color and a 68ohm resistor on the blanking line. because their was no inline capacitor I was going to add it in some jumper locations in the osd rgb color lines near the video processor could I use any 100nF capacitor I have some electrolytic caps that are rated for over 5v and 100nF. I was not going to use diodes which brings me to another question. what is the purpose of removing the grounding resistors and replacing them with a 75ohm resistor is this only necessary when using a diode or does it serve another purpose?

any help would be greatly appriciated.
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