TV RGB mod thread

[vol.2]

Sorry mate, the datasheet suggests that the RGB input is designed only for digital OSD input, not analog RGB.

Damn it. Does that mean I can't RGB mod it at all? Or I just have to give up the OSD?

Almost certainly. TVs of that era set all the inputs in non-volatile memory in the factory. If it wasn't designed to have an RGB input, that input will not be enabled in the settings. Those settings are non user-definable, they are set over an i2C bus with a ROM chip.

It could be possible to dump the existing ROM and reverse engineer the settings by decompiling the ROM and using the jungle IC's datasheet (assuming it's complete enough), but that would be an epic amount of work and it is both beyond the scope of this thread and outside of the wheelhouse of most of us here. You would need someone with a decent level of computer engineering skills and extensive experience with relatively outdated i2C programming

Of course, that's also assuming that there is even some unused RGB input on the jungle IC in the first place.

[lazyelm]

Is the voltage steady at the injection point around 1.1 / 1.2v, and is the voltage from your external source 1.9v steady? If so, this would indicate you have DC bias so you will want to add a coupling capacitor in between your external source and the injection point. 1uf bipolar will probably work, but if you have polar ones point the positive end towards the higher voltage which seems to be external source at the moment. It probably won't hurt to have it anyway while you are testing. If there is a bias offset then I think it could also cause your display to go black when connecting.

The voltage at the injection point is ~1.2v pretty steady yes. External source is .7v. - when i inject, the resulting voltage is ~1.9-2v

I have tried direct but also tried a .1uf cap->75ohm resistor->injection point - same results both ways. Would a 1uf vs a .1uf cap make a difference there? I could try that as well

[Delphius]

Is the voltage steady at the injection point around 1.1 / 1.2v, and is the voltage from your external source 1.9v steady? If so, this would indicate you have DC bias so you will want to add a coupling capacitor in between your external source and the injection point. 1uf bipolar will probably work, but if you have polar ones point the positive end towards the higher voltage which seems to be external source at the moment. It probably won't hurt to have it anyway while you are testing. If there is a bias offset then I think it could also cause your display to go black when connecting.

The voltage at the injection point is ~1.2v pretty steady yes. External source is .7v. - when i inject, the resulting voltage is ~1.9-2v

I have tried direct but also tried a .1uf cap->75ohm resistor->injection point - same results both ways. Would a 1uf vs a .1uf cap make a difference there? I could try that as well

0.1uf is probably fine, or at least you would be getting an image if the biasing was an issue. I would still probably keep it on there while you are testing because it shouldn't hurt anything and if you are getting a steady ~1.2v at the injection point then this indicates it has bias. I would expect at this point that you would see at least some interaction with your external RGB though. Just to clarify, is your OSD affected when you are experimenting?

[lazyelm]

Is the voltage steady at the injection point around 1.1 / 1.2v, and is the voltage from your external source 1.9v steady? If so, this would indicate you have DC bias so you will want to add a coupling capacitor in between your external source and the injection point. 1uf bipolar will probably work, but if you have polar ones point the positive end towards the higher voltage which seems to be external source at the moment. It probably won't hurt to have it anyway while you are testing. If there is a bias offset then I think it could also cause your display to go black when connecting.

The voltage at the injection point is ~1.2v pretty steady yes. External source is .7v. - when i inject, the resulting voltage is ~1.9-2v

I have tried direct but also tried a .1uf cap->75ohm resistor->injection point - same results both ways. Would a 1uf vs a .1uf cap make a difference there? I could try that as well

0.1uf is probably fine, or at least you would be getting an image if the biasing was an issue. I would still probably keep it on there while you are testing because it shouldn't hurt anything and if you are getting a steady ~1.2v at the injection point then this indicates it has bias. I would expect at this point that you would see at least some interaction with your external RGB though. Just to clarify, is your OSD affected when you are experimenting?

Yeah changing resistor values there does impact color Intensity of the green osd text. But I get no image. Black screen. If I hook up another source to the composite image I can impact intensity of rgb as well with the pots but I’m not seeing my injected image. Could it be because the voltage of the bias is 1.2v which is much higher than my injected source?


FWIW. Also tried injecting at the backboard at the base leg on the transistors but the voltage is 12v so I think I would need to ramp up the voltage for that to work on my source


In all these scenarios though I’m getting a black screen I think the blanking and or the source shutoff when it’s not detecting an input from the av inputs is blacking the screen.

[Delphius]

The voltage at the injection point is ~1.2v pretty steady yes. External source is .7v. - when i inject, the resulting voltage is ~1.9-2v

I have tried direct but also tried a .1uf cap->75ohm resistor->injection point - same results both ways. Would a 1uf vs a .1uf cap make a difference there? I could try that as well

0.1uf is probably fine, or at least you would be getting an image if the biasing was an issue. I would still probably keep it on there while you are testing because it shouldn't hurt anything and if you are getting a steady ~1.2v at the injection point then this indicates it has bias. I would expect at this point that you would see at least some interaction with your external RGB though. Just to clarify, is your OSD affected when you are experimenting?

Yeah changing resistor values there does impact color Intensity of the green osd text. But I get no image. Black screen. If I hook up another source to the composite image I can impact intensity of rgb as well with the pots but I’m not seeing my injected image. Could it be because the voltage of the bias is 1.2v which is much higher than my injected source?


FWIW. Also tried injecting at the backboard at the base leg on the transistors but the voltage is 12v so I think I would need to ramp up the voltage for that to work on my source


In all these scenarios though I’m getting a black screen I think the blanking and or the source shutoff when it’s not detecting an input from the av inputs is blacking the screen.

I am sort of out of ideas, but I can try to find some time to study the schematic a little more. I think it is a good sign that the resistor network is having an affect on the OSD when you are injecting, but surprised you aren't seeing any external RGB if you are seeing the OSD. Usually I would expect more interaction, even if it was causing some interference from active buffering or bias on the line.

For injecting into the neck board like that I think there are other mod kits that you can purchase to help. I would be a bit careful injecting there if there is a 12v bias, but especially use the coupling capacitor while experimenting to be a bit safer.

[lazyelm]

0.1uf is probably fine, or at least you would be getting an image if the biasing was an issue. I would still probably keep it on there while you are testing because it shouldn't hurt anything and if you are getting a steady ~1.2v at the injection point then this indicates it has bias. I would expect at this point that you would see at least some interaction with your external RGB though. Just to clarify, is your OSD affected when you are experimenting?

Yeah changing resistor values there does impact color Intensity of the green osd text. But I get no image. Black screen. If I hook up another source to the composite image I can impact intensity of rgb as well with the pots but I’m not seeing my injected image. Could it be because the voltage of the bias is 1.2v which is much higher than my injected source?


FWIW. Also tried injecting at the backboard at the base leg on the transistors but the voltage is 12v so I think I would need to ramp up the voltage for that to work on my source


In all these scenarios though I’m getting a black screen I think the blanking and or the source shutoff when it’s not detecting an input from the av inputs is blacking the screen.

I am sort of out of ideas, but I can try to find some time to study the schematic a little more. I think it is a good sign that the resistor network is having an affect on the OSD when you are injecting, but surprised you aren't seeing any external RGB if you are seeing the OSD. Usually I would expect more interaction, even if it was causing some interference from active buffering or bias on the line.

For injecting into the neck board like that I think there are other mod kits that you can purchase to help. I would be a bit careful injecting there if there is a 12v bias, but especially use the coupling capacitor while experimenting to be a bit safer.

Thanks man I appreciate it. I’m at a loss too

[SkiDragon]

EDIT: I realized I had the 10x on my oscilloscope probe, so the video signal is actually a 5V p-p. Still doesn't look digital, but from my understanding there is no good way to perform a simple RGB mod with a 5V p-p OSD signal. So unless someone has any other idea I am going to give up on this. I will update my picture below. As an aside, I have to fix the convergence now because I discovered the rings were not secured down and the ring assembly was basically freely spinning on the neck.

I've had a Magnavox TS2582 C101 for a couple of years and finally decided to see if I could mod it for RGB. From factory it only has RF, composite, and S-Video. The chassis according to the label on the back of the case is 25R505-00AA
I cannot find the regular owner’s manual, and I do not own a remote for it.
However, I found the service manual for this range of chassis models here:
https://ia801308.us.archive.org/32/item ... 207538.pdf
The service manual does not list the specific type of jungle IC, so I had to open it up.



I removed the main PCB and had to desolder and pry open an EMI shield to find the jungle chip, a TDA8369. It's hard to find much documentation on this chip, but I found a short spec sheet:
https://datasheet4u.com/datasheet/ETC/TDA8369-770219
I hesitate to call it a full datasheet, and it’s a poor quality scan with black blotches making some areas hard to see. However, on the last page I unfortunately did spot the line under Features: "RGB-control circuit with digital OSD input with intensity control"
So, SOL, right? But I had a lot of time to waste today and I started looking up mods for other jungle chips of the TDA836X and TDA837X range (using crtdatabase.com) and it seemed like all the rest had analog inputs. So I decided to poke around some more.
The chip has RGB inputs from a separate OSD chip, but I did not see any coupling capacitors on the schematic or when physically inspecting the board. (There were capacitors to ground)



So, not trusting the crappy datasheet, I decided to hook up my oscilloscope to the Green line between the microprocessor and the TDA8369 Jungle chip.



Luckily, the scope did not blow up which I think verifies that it is not 'hot chassis'.
Here is what the signal looks like when I bring up the menu (and thus triggering the OSD)



Immediately I thought this looked digital and felt disappointed, but I realized an analog signal here would just basically show Green as either On or Off depending on the position in the scan line… so is this analog? I am still not entirely sure of myself. Can anyone chime in? Regardless, the level is 5V and is too high, unless I misunderstand the requirement.

As an aside, in the service manual there was a short blurb saying "Caution: The RS Chassis incorporates a "HOT" ground system. Always use a separate isolation transformer when applying power to the ex-posed chassis."
(I wasn’t sure if that applied to my specific model, and it would be odd I thought for a TV from 1995 with S-Video to be made like this, but it's possible. However mine is not "RS" and I am not sure what chassis that statement is even referring to. Studying the schematic more closely and it looked like the AC was in fact isolated through a transformer. There was continuity between the existing RCA jack shields and various grounds on the main board, including pin 13 GND on the actual jungle chip. I also did a diode test on between the two sides of the AC plug and the RCA jack shield, both prongs and both polarities and it was all reading as no connection. So I risked it, and so far seems to be fine.)

TLDR:
I am trying to figure out if that signal is analog and if/how I should proceed to attempting a RGB mod, preferably muxed but switched if need be.

[Delphius]

I've had a Magnavox TS2582 C101 for a couple of years and finally decided to see if I could mod it for RGB. From factory it only has RF, composite, and S-Video. The chassis according to the label on the back of the case is 25R505-00AA
I cannot find the regular owner’s manual, and I do not own a remote for it.
However, I found the service manual for this range of chassis models here:
https://ia801308.us.archive.org/32/item ... 207538.pdf
The service manual does not list the specific type of jungle IC, so I had to open it up.

https://ibb.co/0psWGZfw

I removed the main PCB and had to desolder and pry open an EMI shield to find the jungle chip, a TDA8369. It's hard to find much documentation on this chip, but I found a short spec sheet:
https://datasheet4u.com/datasheet/ETC/TDA8369-770219
I hesitate to call it a full datasheet, and it’s a poor quality scan with black blotches making some areas hard to see. However, on the last page I unfortunately did spot the line under Features: "RGB-control circuit with digital OSD input with intensity control"
So, SOL, right? But I had a lot of time to waste today and I started looking up mods for other jungle chips of the TDA836X and TDA837X range (using crtdatabase.com) and it seemed like all the rest had analog inputs. So I decided to poke around some more.
The chip has RGB inputs from a separate OSD chip, but I did not see any coupling capacitors on the schematic or when physically inspecting the board. (There were capacitors to ground)

https://ibb.co/zHWLxjHd

So, not trusting the crappy datasheet, I decided to hook up my oscilloscope to the Green line between the microprocessor and the TDA8369 Jungle chip.

https://ibb.co/Kp1VFndC

Luckily, the scope did not blow up which I think verifies that it is not 'hot chassis'.
Here is what the signal looks like when I am adjusting the volume (and thus triggering the OSD)

https://ibb.co/wNhfbKgp

Immediately I thought this looked digital and felt disappointed, but I realized an analog signal here would just basically show Green as either On or Off depending on the position in the scan line… so is this analog? I am still not entirely sure of myself. Can anyone chime in?

As an aside, in the service manual there was a short blurb saying "Caution: The RS Chassis incorporates a "HOT" ground system. Always use a separate isolation transformer when applying power to the ex-posed chassis."
(I wasn’t sure if that applied to my specific model, and it would be odd I thought for a TV from 1995 with S-Video to be made like this, but it's possible. However mine is not "RS" and I am not sure what chassis that statement is even referring to. Studying the schematic more closely and it looked like the AC was in fact isolated through a transformer. There was continuity between the existing RCA jack shields and various grounds on the main board, including pin 13 GND on the actual jungle chip. I also did a diode test on between the two sides of the AC plug and the RCA jack shield, both prongs and both polarities and it was all reading as no connection. So I risked it, and so far seems to be fine.)

TLDR:
I am trying to figure out if that signal is analog and if/how I should proceed to attempting a RGB mod, preferably muxed but switched if need be.

I don't have any experience scoping out digital OSD signals, but it would seem to me that if there are separate channels for each RGB input signals then they are probably analog. I could be totally wrong, but I don't understand the logic behind separating a digital signal for each RGB channel. I would assume they would combine those into one digital signal and encode through a clock. It seems to be 5Vpp, so maybe it is worth a try as long as you keep it in that voltage range.

[SkiDragon]

Well, unfortunately it looks like my TV uses digital RGB. I decided to makeshift an RGB cable for my PS1 to test it out and these were the results:

https://imgur.com/a/ad8Y8de

It's a shame it didn't work, but nonetheless, I enjoyed the experience, and I think I learned a few useful things. Maybe someday I'll own a CRT that can be RGB modded; then I can put the knowledge I gained to use, but until then I'll be happy with my 9-inch CRT and its composite inputs.

I know this post is a year and a half old, but if this person's jungle chip expects a digital signal from the OSD chip, and they injected an analog signal into this input, why are they getting an image that looks close to correct? Normally an analog output into a digital input would not work in the slightest. Like, imagine putting composite video into your HDMI port, totally bonkers.

So, what is meant by 'digital' here. Do people just mean 'discretized', or something like that?

[gabnattz]

Hey folks, I found this TV Philips 14GL1316/78R with the Chassis GR1-L1 which possibly has a TDA8361/N3 and apparently it has RGB inputs with 0.7Vpp for RGB OSD.

I'm trying to understand better but I'm having a hard time to find the complete schematics manual but found this one.
Can you guys give me a hand and check if the RGB inputs are analog to inject a RGB mod into it?
Thanks for your help in advance!

[MarkOZLAD]

Hey folks, I found this TV Philips 14GL1316/78R with the Chassis GR1-L1 which possibly has a TDA8361/N3 and apparently it has RGB inputs with 0.7Vpp for RGB OSD.

I'm trying to understand better but I'm having a hard time to find the complete schematics manual but found this one.
Can you guys give me a hand and check if the RGB inputs are analog to inject a RGB mod into it?
Thanks for your help in advance!

These chips are generally a straightforward OSD mix.

Get the data sheet for the jungle and possibly micom. Using a multimeter graph out the OSD RGB and blanking circuits, then do a mux on the factory “grounding” resistors of RGB.


For blanking you will see a similar pattern but different resistor values. Can still do a mux on it. Report back and we can help.

[gabnattz]

Hey folks, I found this TV Philips 14GL1316/78R with the Chassis GR1-L1 which possibly has a TDA8361/N3 and apparently it has RGB inputs with 0.7Vpp for RGB OSD.

I'm trying to understand better but I'm having a hard time to find the complete schematics manual but found this one.
Can you guys give me a hand and check if the RGB inputs are analog to inject a RGB mod into it?
Thanks for your help in advance!

These chips are generally a straightforward OSD mix.

Get the data sheet for the jungle and possibly micom. Using a multimeter graph out the OSD RGB and blanking circuits, then do a mux on the factory “grounding” resistors of RGB.


For blanking you will see a similar pattern but different resistor values. Can still do a mux on it. Report back and we can help.

Stumbled by another set which seems to be the same idea of this past one, the Jungle is a Toshiba TA8808BN and the Micom is a LG8438-22F(which I couldn't find any datasheet of it). Found the schematics and took some pictures of it, but it is pretty nasty on it's insides and I'm gonna clean a bit.
It's a Gradiente GT-1422BP(Brazillian brand) which mix components of other brands on it hahaha

[gabnattz]

[/img]752708170 user_id=24758]
Hey folks, I found this TV Philips 14GL1316/78R with the Chassis GR1-L1 which possibly has a TDA8361/N3 and apparently it has RGB inputs with 0.7Vpp for RGB OSD.

I'm trying to understand better but I'm having a hard time to find the complete schematics manual but found this one.
Can you guys give me a hand and check if the RGB inputs are analog to inject a RGB mod into it?
Thanks for your help in advance!

These chips are generally a straightforward OSD mix.

Get the data sheet for the jungle and possibly micom. Using a multimeter graph out the OSD RGB and blanking circuits, then do a mux on the factory “grounding” resistors of RGB.


For blanking you will see a similar pattern but different resistor values. Can still do a mux on it. Report back and we can help.

Stumbled by another set which seems to be the same idea of this past one, the Jungle is a Toshiba TA8808BN and the Micom is a LG8438-22F(which I couldn't find any datasheet of it). Found the schematics and took some pictures of it, but it is pretty nasty on it's insides and I'm gonna clean a bit.
It's a Gradiente GT-1422BP(Brazillian brand) which mix components of other brands on it hahaha

Gave it a try but couldn't figure out what resistors to use or remove, the image bellow is what I've attempted.
I think I'm so close to getting it working but need your professional help

[gabnattz]

For the sake of my quotes being utterly big, I'm posting a update on a new reply.
I'm very very close to get it good, I've poked a bit and tried things out before figuring out how to get the correct values on the Sunthar's calculator.
It is working, switching correctly the RGB signals, the colors seem right but the image is too bright, the blacks aren't really blacks and there are some green lines appearing on screen

That's a rough sketch of what I've made to achieve this, any help would be gladly appreciated!

[Delphius]

For the sake of my quotes being utterly big, I'm posting a update on a new reply.
I'm very very close to get it good, I've poked a bit and tried things out before figuring out how to get the correct values on the Sunthar's calculator.
It is working, switching correctly the RGB signals, the colors seem right but the image is too bright, the blacks aren't really blacks and there are some green lines appearing on screen

That's a rough sketch of what I've made to achieve this, any help would be gladly appreciated!

Check if there is a bias on the lines where you are injecting. Or if have any 0.1uf or 1uf caps around you can try and place them in series with your external RGB injection.

[MarkOZLAD]

lol “Sunthar’s calculator”….

[gabnattz]

lol “Sunthar’s calculator”….

Forgot to mention the mind behind it, so sorry, master!

[gabnattz]

lol “Sunthar’s calculator”….

Forgot to mention the mind behind it, so sorry, master!

If there's any Brazillian here wanting to try it out, good luck!
That's the final revision which would let this mod be perfect for what this TV set is.
Profound thanks to Syntax, MarkOZLAD and Sunthar for your work and community help!

Results

[Ryeno]

Sorry mate, the datasheet suggests that the RGB input is designed only for digital OSD input, not analog RGB.
[/quote]

Damn it. Does that mean I can't RGB mod it at all? Or I just have to give up the OSD?
[/quote]

https://archive.org/details/panasonic_ct-13R_ct-27g

this service manual shows 5v, 2.2k series. 33k shunt for the voltage divider. no coupling capacitor. so maybe RGB mod will work but you'd need to use the video amp, ac couple input and dc couple the output. read my post about the Panasonic CT-S1390Y

[Kvazikvark]

Hello everyone, haven't written on the forum in ages!
Yeah, I still haven't finished with my little Panasonic, just haven't had the time =(

Recently, I managed to get two more CRT TVs. One is a Sony Trinitron KV-25R1R, and the other is a Panasonic TC-21L3R. Slightly off-topic, I know, but unfortunately, the Trinitron has a worn-out CRT. My joy quickly turned to frustration (the brightness and contrast are very low, and adjusting the service menu settings didn't help at all). However, the Panasonic is in literally perfect condition, surprisingly. Out of the 6 CRTs I have now, only the Panasonics have been perfectly preserved. Alas, this model also lacks SCART RGB, so I'll have to rig it up myself. Has anyone worked with this specific model?

[MarkOZLAD]

If the Panasonic TC-21L3R is an MX-5 chassis as co-pilot suggests…it’s an osd mux through the E9 header.

[Kvazikvark]

I found information that the Panasonic TC-21L3R is based on the MX-1A chassis with the AN5606K jungle chip. I couldn't find any information in the chip's documentation about the Vpp levels of the RGB signal it accepts.

MX-1A

datasheet

AN5606K

datasheet

[Pyro925]

Hi all, Ive got a secure view I'm modding for a friend. As far as I can tell it'll be very similar to https://imgur.com/a/rca-secureview-pris ... od-wpOgwCV but I'm trying to wire in a YPbPr connections instead of bnc


I'm a little confused if I'll need to change the resistor values, what the yellow composite is doing, and what the spdt switch actually is/how it's wired in?
Sorry for the dummy questions, I'm new to the hobby and want to this good. Any help is appreciated! Thanks!

[Infinite Returning]

Hi Everyone! Was reading your awesome advices for 5 years +, but now I really need help and can't find solution anywhere

I have scored super rare Sony KV-2553MT with GP-1A chassis and junglechip SONY CXA1213S. Unfortunately any injection RGB mod is not possible, but I have learned there is RGB Amp mod, that was invented about 11 months ago. It requires to build separate board with RGB inputs and outputs connected directely to the neckboard. Can anyone help me to build such board and add audio there? I have base schematics, but it lacks H Center control, Contrast control and so on and no audio. I want to build universal board with potentiometers and audio and add scart there. There is something like that on Aliexpress, but I do not like the looks, do not trust quality and price is overkill too. Will be cool to develop our own scheme and made it free for all with PCB design and parts list anyone can solder at home.
Hope someone can help me with this since this TV is awesome and looks like oldschool PVM.

[Kvazikvark]

If the Panasonic TC-21L3R is an MX-5 chassis as co-pilot suggests…it’s an osd mux through the E9 header.

By the way, I'm going to do a basic RGB mod first, not MUX, since I'm not sure this Panasonic won't give me surprises like the previous one did. If everything goes well, then I can think about doing the MUX mod. Though, I have to admit, I just like the toggle lever itself =)

[Ryeno]

Hi Everyone! Was reading your awesome advices for 5 years +, but now I really need help and can't find solution anywhere

I have scored super rare Sony KV-2553MT with GP-1A chassis and junglechip SONY CXA1213S. Unfortunately any injection RGB mod is not possible, but I have learned there is RGB Amp mod, that was invented about 11 months ago. It requires to build separate board with RGB inputs and outputs connected directely to the neckboard. Can anyone help me to build such board and add audio there? I have base schematics, but it lacks H Center control, Contrast control and so on and no audio. I want to build universal board with potentiometers and audio and add scart there. There is something like that on Aliexpress, but I do not like the looks, do not trust quality and price is overkill too. Will be cool to develop our own scheme and made it free for all with PCB design and parts list anyone can solder at home.
Hope someone can help me with this since this TV is awesome and looks like oldschool PVM.

it's a hot chassis. you can do the s-video mod for it .

https://www.reddit.com/r/crtgaming/comm ... t/m5wi2x0/

[Infinite Returning]

Hi Everyone! Was reading your awesome advices for 5 years +, but now I really need help and can't find solution anywhere

I have scored super rare Sony KV-2553MT with GP-1A chassis and junglechip SONY CXA1213S. Unfortunately any injection RGB mod is not possible, but I have learned there is RGB Amp mod, that was invented about 11 months ago. It requires to build separate board with RGB inputs and outputs connected directely to the neckboard. Can anyone help me to build such board and add audio there? I have base schematics, but it lacks H Center control, Contrast control and so on and no audio. I want to build universal board with potentiometers and audio and add scart there. There is something like that on Aliexpress, but I do not like the looks, do not trust quality and price is overkill too. Will be cool to develop our own scheme and made it free for all with PCB design and parts list anyone can solder at home.
Hope someone can help me with this since this TV is awesome and looks like oldschool PVM.

it's a hot chassis. you can do the s-video mod for it .

https://www.reddit.com/r/crtgaming/comm ... t/m5wi2x0/

It has S-video already. So it is not safe to so any RGB mod since it is hot chasis?

[Kvazikvark]

Hi Everyone! Was reading your awesome advices for 5 years +, but now I really need help and can't find solution anywhere

I have scored super rare Sony KV-2553MT with GP-1A chassis and junglechip SONY CXA1213S. Unfortunately any injection RGB mod is not possible, but I have learned there is RGB Amp mod, that was invented about 11 months ago. It requires to build separate board with RGB inputs and outputs connected directely to the neckboard. Can anyone help me to build such board and add audio there? I have base schematics, but it lacks H Center control, Contrast control and so on and no audio. I want to build universal board with potentiometers and audio and add scart there. There is something like that on Aliexpress, but I do not like the looks, do not trust quality and price is overkill too. Will be cool to develop our own scheme and made it free for all with PCB design and parts list anyone can solder at home.
Hope someone can help me with this since this TV is awesome and looks like oldschool PVM.

I really like your idea. It would be ideal to create a universal device that could be connected directly to any CRT to output an RGB signal to it. This would solve so many problems and streamline the modification process into a single standard. But to implement this idea, we'd need to do some research and figure everything out properly – that would require a lot of time.
***
After reading up on the topic, it seems practically impossible and rather impractical to make such a device. It simply couldn't be universal due to the different parameters of each CRT. You'd have to either find or somehow measure those parameters, which would require equipment like an oscilloscope – and that's not exactly cheap.