TV RGB mod thread

The place for all discussion on gaming hardware
Michel_K17
Posts: 4
Joined: Sun Oct 31, 2021 2:23 am

Re: TV RGB mod thread

Post by Michel_K17 »

MarkOZLAD wrote:Image

This is how I think the RGB input with DC offset could work. Interested in feedback.

Not quite sure how to Mux it yet. Still thinking about that.
I have had success with a similar DC offset circuit, but applied it to each color (R, G, B) individually so that I could adjust/balance each of the colors.
Michel "K-17"
mink2022
Posts: 2
Joined: Wed Jun 01, 2022 9:30 am

Re: TV RGB mod thread

Post by mink2022 »

Hi all. I'm looking in to modding this JVC N-Series 20NT11 with TB1230AN chroma ic.
It has an unused Analog RGB input and a separate Digital RGB for the OSD.
I have someone over at Reddit helping me with it but im looking for a 2nd opinion before i crack this tv open, that i wont be needing to hack the eeprom rom something to enable it.

Heres the circuit diagram of it
Image

And here's the jungle
Image

Solder side of the board.
Image

Here are the complete manual for the set and chroma
https://drive.google.com/drive/folders/ ... 6-mdJBVyeu
User avatar
PacManPlus
Posts: 25
Joined: Sun Apr 03, 2022 9:40 pm
Location: SW Florida, USA

Re: TV RGB mod thread

Post by PacManPlus »

Hello all, sorry to interrupt.

Aside from the Magnavox 13" I bought in my other thread, I picked up a Sony KV-24FS100 for $50. I looked through here, saw some posts on that TV, but nothing that really has any information on how to work with it.
I compared it to the KV-27FS100, but unfortunately the boards in them were completely different.
However I did find the service manual for this: https://www.manualslib.com/manual/95222 ... fs100.html

There seems to be only one chip in it (again, like the Magnavox) :(
But, I see where there is R G B out from that chip, and I'm thinking I can intercept those signals... The only thing that confuses me is that I don't see any blanking signal to raise:
Image

I see that R, G, and B, are pins 31, 33, and 35, respectively, and I'm hoping I can kill those and inject the external RGB signal and the 75 Ohm resistors to each. But I need to find the blanking pin. I just hope I'm not way off here.
Does anything look like a blanking signal in this pinout?

Thank you, sorry to bother anyone.
Bob
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

PacManPlus wrote:Hello all, sorry to interrupt.

Aside from the Magnavox 13" I bought in my other thread, I picked up a Sony KV-24FS100 for $50. I looked through here, saw some posts on that TV, but nothing that really has any information on how to work with it.
I compared it to the KV-27FS100, but unfortunately the boards in them were completely different.
However I did find the service manual for this: https://www.manualslib.com/manual/95222 ... fs100.html

There seems to be only one chip in it (again, like the Magnavox) :(
But, I see where there is R G B out from that chip, and I'm thinking I can intercept those signals... The only thing that confuses me is that I don't see any blanking signal to raise:
Image

I see that R, G, and B, are pins 31, 33, and 35, respectively, and I'm hoping I can kill those and inject the external RGB signal and the 75 Ohm resistors to each. But I need to find the blanking pin. I just hope I'm not way off here.
Does anything look like a blanking signal in this pinout?

Thank you, sorry to bother anyone.
Bob
The 20FS100 is a BA-6 chassis just like the 27FS120 so it has a combined jungle and micon chip and cannot be RGB modded easily. But you do have YUV inputs so you could buy or build an RGB to YUV (Component) adapter and use that. Set AXNT to 0 in the service menu and possibly 0 out the VM too.
User avatar
PacManPlus
Posts: 25
Joined: Sun Apr 03, 2022 9:40 pm
Location: SW Florida, USA

Re: TV RGB mod thread

Post by PacManPlus »

Ok. Damn. Again. I can't seem to win with this stuff. I'll try the RGB to YUV and see if the picture looks ok (and of course change the settings you suggested as well).

Thank you for the explanation.
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

PacManPlus wrote:Ok. Damn. Again. I can't seem to win with this stuff. I'll try the RGB to YUV and see if the picture looks ok (and of course change the settings you suggested as well).

Thank you for the explanation.
If you build this the quality should be nearly identical to RGB mod.

http://elm-chan.org/works/yuv2rgb/report.html
http://elm-chan.org/works/yuv2rgb/rw/rgb2yuv.png

A 20" is kinda rare. From what I've seen most TVs tend to be 13" or 27". I would keep it and calibrate it. How is the geometry.
User avatar
PacManPlus
Posts: 25
Joined: Sun Apr 03, 2022 9:40 pm
Location: SW Florida, USA

Re: TV RGB mod thread

Post by PacManPlus »

Thank you!

Although it's a 24" (24FS100) tube.

I was thinking of getting this: https://www.ebay.com/itm/144508012360?h ... SwthpiWtkf
(The second picture shows the RGBs input and the YUV output.) You think that should be ok?

The geometry *seems* to be ok, although my 'testing' board is only a Pac-Man Plus arcade board. (I'm doing all of my recent testing with a Pac/Ms. Pac board as I'm out of Galaga ones ATM)
User avatar
matt
Posts: 567
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Re: TV RGB mod thread

Post by matt »

Not sure about that one, but I use a Retrotink RGB2Comp with my 24" Wega and it's perfect. There's no visible difference between its output and native RGB.

https://www.retrotink.com/product-page/rgb2comp

This converter is also popular. He makes one with a VGA input too if you check his other listings:

https://www.ebay.com/itm/174166352622?h ... SwgMxc-BD-
User avatar
PacManPlus
Posts: 25
Joined: Sun Apr 03, 2022 9:40 pm
Location: SW Florida, USA

Re: TV RGB mod thread

Post by PacManPlus »

Thank you Matt!

That first one I actually saw, but I'm in the states and have no Scart connector. :(
That's why when I saw the one I posted above on e-Bay, which actually has RCA inputs for RGBs (as well as the Scart connector), I figured that was the one. :)

Thanks again,
Bob
User avatar
matt
Posts: 567
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Re: TV RGB mod thread

Post by matt »

Even in the US, SCART cables are probably the easiest type of ready made RGB cables to find.

But, making your own cables is easy and saves money - in which case you can use whatever connector you want!
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

evilsim wrote:Today I found a childrens CRT in a second hand store, so picked it up just because it would be cool for my kid to use. Its a 34cm TV shaped like Lightening McQueen from Disney Cars - lol. It was CIB with unopened bits, basically brand new.
Image
It took a long time to open it, so many screws, even had to take the plastic wheel nuts off to reveal more hidden screws.
After all the effort - a nice easy RGB mod was available. The TV had an unused bunch of scart pins (all 21) ready to solder a header onto. I could not get the blanking/rgb to work via that but found elsewhere on the mainboard a location which looked good, FB / AV / RGB pins all just waiting to be raided. 12v on the fast blanking pin and wallah I have a nice RGB image. This has to be the easiest RGB mod ive done since my first Sony TV which was just soldering wires, no caps or resistors required.
The TV is a china special, the tube was made in 2007 ! Picture is good but I like to be able to shift the image horizontally a little (good luck getting into the service menu of this guy). I couldn't see the Jungle as it was covered in a heavily-soldered on shield, kinda like the shielding u find on a 3d0 / megadrive2 console, but more and thicker. I didn't need to see the jungle in the end.
Image
Image


edit: lukilla, yeah the picture isnt amazing, but no worse than a lot of other consumer sets. if its possible could you link me to the manual for the TV, I might be able to shift this thing to the left a little ? i used CN303 header to mod this one (R/G/B/FB+AV1), then ran the wires to a 8 pin mini din socket (audio attached too).
Just pushing my luck in here, i know its been over 5 years, but i was wondering, do you still have this moded tvor do you have pictures of the mod by any chance? i just found 2 tvs of the same model. Hope i get lucky.
kwd114
Posts: 5
Joined: Sat Jun 11, 2022 7:07 pm

Re: TV RGB mod thread

Post by kwd114 »

Hey all,

Working on a Magnavox FS2762. Pulled the following info out of the service manual for the chassis. Set has a TDA8369 Jungle.

So I should be able to inject the RGB on pins 23,24, and 25. Tracing back from IC200 looks the there are inline 222ohm resistors, so with the 75 ohm to ground I would be looking at 147ohm addition.

One thing I cant figure is the blanking a standard 5V on-off switch? Blanking feeds into pin 26 of IC300 from pin30 of IC200. This is feed through a 1.5KOhm resistor. So is my blanking 5V through a 1.5KOhm resistor?


Image
Image


*****Update*****

So after further investigation it looks like this jungle is using digital RGB according to the datasheet that I found. If I am wrong someone can correct me but I think I will be just keeping this set stock. My NES needs a home anyway!
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

mink2022 wrote:Hi all. I'm looking in to modding this JVC N-Series 20NT11 with TB1230AN chroma ic.
It has an unused Analog RGB input and a separate Digital RGB for the OSD.
I have someone over at Reddit helping me with it but im looking for a 2nd opinion before i crack this tv open, that i wont be needing to hack the eeprom rom something to enable it.
Grab 5V from the motherboard, run it through a 180 ohm and 75 ohm voltage divider into the YS pin to test blanking.
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

Ryeno wrote:
Minitron wrote:so much for this detailed response! Final question, if I may... Your assessment takes into account that there are capacitors here coming from the OSD just after the 5.6k resistors? Just want to be as close to 100% sure as I can be here. Again, thank you so much for your help. You went above and beyond!
Nice catch. Those are filter caps. You should remove them on the RGB because they'll form a RC low pass filter with the 820ohm resistors. You should be fine without filter caps but If you want to add the filter caps back into the circuit then get 3 ~3.3pF ceramic caps C0G NP0 and install them parallel with the 75 ohm termination resistors to ground.

https://www.digikey.com/en/products/det ... 06/5802809

You can keep the filter cap on the blanking line. it shouldn't affect the circuit.
Thanks again for response. So I wired exactly as you said. Unfortunately, I'm getting really messed up picture. I assume this is from sync? Image

I wired it directly to the composite input. The images in the picture are scrolling upward 1000x a second lol
The composite input goes through this circuit before entering the jungle chip:

Image

To provide more detail, the images that are scrolling appear to be correct. The colors are in the right places and everything. They are just scrolling really fast. Should i be wiring the sync directly into the jungle, bypassing the circuitry that goes from Composite In? Or should i wire the sync into Luma?
Last edited by Minitron on Fri Jun 24, 2022 9:27 pm, edited 2 times in total.
Michel_K17
Posts: 4
Joined: Sun Oct 31, 2021 2:23 am

Re: TV RGB mod thread

Post by Michel_K17 »

MarkOZLAD wrote:Image

This is how I think the RGB input with DC offset could work. Interested in feedback.

Not quite sure how to Mux it yet. Still thinking about that.
I used the same DC offset logic with my own circuit which worked well, but I had each color (R, G, B) with their own resistor and pot so I could balance them independently.
Michel "K-17"
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

Minitron wrote:To provide more detail, the images that are scrolling appear to be correct. The colors are in the right places and everything. They are just scrolling really fast. Should i be wiring the sync directly into the jungle, bypassing the circuitry that goes from Composite In? Or should i wire the sync into Luma?
Are you on the correct video input?

You should usually not wire sync directly into the jungle chip. I generally recommend running sync into luma if the set has the s-video option. Some sets have combo composite/s-video inputs and you must bridge the s-video input to enable it.
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

Ryeno wrote:
Minitron wrote:To provide more detail, the images that are scrolling appear to be correct. The colors are in the right places and everything. They are just scrolling really fast. Should i be wiring the sync directly into the jungle, bypassing the circuitry that goes from Composite In? Or should i wire the sync into Luma?
Are you on the correct video input?

You should usually not wire sync directly into the jungle chip. I generally recommend running sync into luma if the set has the s-video option. Some sets have combo composite/s-video inputs and you must bridge the s-video input to enable it.
Ah, yes i do have composite and S-video in. The input seems to change automatically according to what is plugged in, there is no remote with this set, or any option on the set to switch inputs. Side note, tested both S-video and composite and they work just fine. Any chance blanking could be the issue?

What do you mean by bridging the s-video input? Tomorrow i will attempt running sync to luma. Thank you so much for responses. I am such a noob.
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

Minitron wrote:
Ryeno wrote:
Minitron wrote:To provide more detail, the images that are scrolling appear to be correct. The colors are in the right places and everything. They are just scrolling really fast. Should i be wiring the sync directly into the jungle, bypassing the circuitry that goes from Composite In? Or should i wire the sync into Luma?
Are you on the correct video input?

You should usually not wire sync directly into the jungle chip. I generally recommend running sync into luma if the set has the s-video option. Some sets have combo composite/s-video inputs and you must bridge the s-video input to enable it.
Ah, yes i do have composite and S-video in. The input seems to change automatically according to what is plugged in, there is no remote with this set, or any option on the set to switch inputs. Side note, tested both S-video and composite and they work just fine. Any chance blanking could be the issue?

What do you mean by bridging the s-video input? Tomorrow i will attempt running sync to luma. Thank you so much for responses. I am such a noob.
The issue is sync. How are you injecting sync? If you wire scart pin 20 directly to R162, C3209/R3209 or R3007, the sync should work.
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

Ryeno wrote: The issue is sync. How are you injecting sync? If you wire scart pin 20 directly to R162, C3209/R3209 or R3007, the sync should work.
Thanks for clarification. I injected sync right on R3007. I also just tested Luma and got the same result. I actually disconnected sync altogether and got the exact same result again. Not sure what to try next... I'm deep in thought but no ideas. Any chance it is the way i grounded something? Am i to split the grounds to different places? I believe i wired the AV ground right to AV ground, on its own line. (Sync is wired to pin 20)

Edit: Also wondering if i maybe overshot the Blank, as the chip accepts only up to 3.3v? Maybe the autoswitch is cutting off composite/s-video at that point?

Here's the sheet for the jungle:
https://datasheetspdf.com/pdf/387244/Mi ... 52770ASP/1
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

Minitron wrote:
Ryeno wrote: The issue is sync. How are you injecting sync? If you wire scart pin 20 directly to R162, C3209/R3209 or R3007, the sync should work.
Thanks for clarification. I injected sync right on R3007. I also just tested Luma and got the same result. I actually disconnected sync altogether and got the exact same result again. Not sure what to try next... I'm deep in thought but no ideas. Any chance it is the way i grounded something? Am i to split the grounds to different places? I believe i wired the AV ground right to AV ground, on its own line.

Edit: Also wondering if i maybe overshot the Blank, as the chip accepts only up to 3.3v? Maybe the autoswitch is cutting off composite/s-video at that point?

Here's the sheet for the jungle:
https://datasheetspdf.com/pdf/387244/Mi ... 52770ASP/1
The grounds are for shielding from interference. They won't cause a no signal issue.

I would recommend tracing the circuit because that service manual is for the European version without S-Video so it doesn't show how composite/s-video switching is controlled.
Last edited by Ryeno on Fri Jun 24, 2022 11:39 pm, edited 1 time in total.
User avatar
cools
Posts: 2055
Joined: Mon Nov 26, 2007 4:57 pm
Location: South Wales
Contact:

Re: TV RGB mod thread

Post by cools »

I have a Toshiba 3357DB with a problem, RGB is about 50% brightness.

Composite, S-Video and the OSD are fully bright.

RGB SCART goes directly to a Teletext/RGB switcher, and from there into a TA1222AN jungle chip, with the R G B lines each passing through a 0.1uF plastic film capacitor. Both Teletext and RGB are the same low brightness, including when mixed.

I've so far socketed the Teletext/RGB switching chip in case that was at fault. Replacing the chip, removing (and bypassing) the chip, and even bypassing the entire switching PCB have shown no improvement.

I'll replace those PF capacitors next (is it feasible those could cause this?), but if that doesn't help matters, could it really be a faulty jungle chip?

(I'd rather not go down OSD modding a set that should handle RGB properly if I can help it)
Image
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

cools wrote:I have a Toshiba 3357DB with a problem, RGB is about 50% brightness.

Composite, S-Video and the OSD are fully bright.

RGB SCART goes directly to a Teletext/RGB switcher, and from there into a TA1222AN jungle chip, with the R G B lines each passing through a 0.1uF plastic film capacitor. Both Teletext and RGB are the same low brightness, including when mixed.

I've so far socketed the Teletext/RGB switching chip in case that was at fault. Replacing the chip, removing (and bypassing) the chip, and even bypassing the entire switching PCB have shown no improvement.

I'll replace those PF capacitors next (is it feasible those could cause this?), but if that doesn't help matters, could it really be a faulty jungle chip?

(I'd rather not go down OSD modding a set that should handle RGB properly if I can help it)
The issue is with blanking (YS). Measure the voltage at Pin 32. It could be a bad jungle chip but more likely the issue is with a resistor or maybe bad solder point.

Did you try different consoles? It's possible the blanking signal is weak from the console.

https://www.520101.com/html/circuitry/122626360.html
User avatar
cools
Posts: 2055
Joined: Mon Nov 26, 2007 4:57 pm
Location: South Wales
Contact:

Re: TV RGB mod thread

Post by cools »

Ryeno wrote:
cools wrote:I have a Toshiba 3357DB with a problem, RGB is about 50% brightness.

Composite, S-Video and the OSD are fully bright.

RGB SCART goes directly to a Teletext/RGB switcher, and from there into a TA1222AN jungle chip, with the R G B lines each passing through a 0.1uF plastic film capacitor. Both Teletext and RGB are the same low brightness, including when mixed.

I've so far socketed the Teletext/RGB switching chip in case that was at fault. Replacing the chip, removing (and bypassing) the chip, and even bypassing the entire switching PCB have shown no improvement.

I'll replace those PF capacitors next (is it feasible those could cause this?), but if that doesn't help matters, could it really be a faulty jungle chip?

(I'd rather not go down OSD modding a set that should handle RGB properly if I can help it)
The issue is with blanking (YS). Measure the voltage at Pin 32. It could be a bad jungle chip but more likely the issue is with a resistor or maybe bad solder point.

Did you try different consoles? It's possible the blanking signal is weak from the console.

https://www.520101.com/html/circuitry/122626360.html
I'll take a look at that tomorrow, thank you. I've tried multiple different sources, they are all exactly the same.
Image
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

Ryeno wrote: I would recommend tracing the circuit because that service manual is for the European version without S-Video so it doesn't show how composite/s-video switching is controlled.
Ah. I didn't realize the models were different! Okay. Which circuit should I try to trace? Blank, I assume? Is there something specific I am looking for?
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

Minitron wrote:
Ryeno wrote: I would recommend tracing the circuit because that service manual is for the European version without S-Video so it doesn't show how composite/s-video switching is controlled.
Ah. I didn't realize the models were different! Okay. Which circuit should I try to trace? Blank, I assume? Is there something specific I am looking for?
From the composite and s-video jacks to the Jungle chip and ground. Pins 33, 35, 43 and 45. You want to figure out how the circuit switches between inputs.
cools wrote:
I'll take a look at that tomorrow, thank you. I've tried multiple different sources, they are all exactly the same.
First step is to measure from scart pin 16 to 21 for 75 ohms.
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

RGB Mux Mod is complete!

MASSIVE thank you to Ryeno for holding my hand through this!(as it turns out I had something wired to the wrong spot!) You went above and beyond and I seriously appreciate it. You are an internet hero!

Image

This is the schematic I used. Wiring the blank/RGB grounds to the SCART connector is not necessary. Just wire the 75ohm to the TV's internal grounds.

Image

Image
Michel_K17
Posts: 4
Joined: Sun Oct 31, 2021 2:23 am

Re: TV RGB mod thread

Post by Michel_K17 »

Nice! Love the quality of the image. :D
Michel "K-17"
Minitron
Posts: 16
Joined: Fri Apr 01, 2022 2:25 am

Re: TV RGB mod thread

Post by Minitron »

Michel_K17 wrote:Nice! Love the quality of the image. :D
Thanks! :D I'm very happy with it! I don't know why the second picture ended up being GIGANTIC as they were both taken by the same camera, with the same settings lmao but whatevs. Sorry guys!
MarkOZLAD
Posts: 1004
Joined: Thu May 18, 2017 12:39 pm

Re: TV RGB mod thread

Post by MarkOZLAD »

Ryeno wrote: I figured out the problem. This TV needs a DC clamped circuit. I built a simple OP amp clamper circuit and I got RGB properly working. I'll post more later.

https://www.maximintegrated.com/en/desi ... /3303.html

https://www.youtube.com/watch?v=xU7nGvADHZM
Hey Ryeno,

I'm very interested in what you came up with if you get the time to document, I have a couple of these troublesome Panasonics lying around.

Cheers,

MarkOZLAD
___________________________________________________
MarkOZLAD
OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p

"Imagine toggle switch OSD modding a TV in 2019" - maxtherabbit
Ryeno
Posts: 89
Joined: Tue Nov 05, 2019 6:50 am

Re: TV RGB mod thread

Post by Ryeno »

MarkOZLAD wrote:
Ryeno wrote: I figured out the problem. This TV needs a DC clamped circuit. I built a simple OP amp clamper circuit and I got RGB properly working. I'll post more later.

https://www.maximintegrated.com/en/desi ... /3303.html

https://www.youtube.com/watch?v=xU7nGvADHZM
Hey Ryeno,

I'm very interested in what you came up with if you get the time to document, I have a couple of these troublesome Panasonics lying around.

Cheers,

MarkOZLAD
You must use a DC clamp circuit. You can either use a dedicated op amp or use the typical TI RGB amp since it features a built-in clamping circuit.


This is the schematic for the Panasonic CT-S1390Y.

Image

RGB
I removed the OSD R1 resistors (R040,R041,R043) and replaced them with 430 ohm resistors and I used that location to fed into the op amps. If using the dedicated DC restore circuit then you want to remove the OSD R2 resistors (R044,R045,R047) but if using the TI RGB amp then you'll want to replace them with 75 ohm resistors. The rest of the wiring is self explanatory

Blanking
I had some trouble getting blanking to work. I found the easiest solution to be swamping around some of the resistors. Replace R048 (2.2k) with a 75 ohm resistor. Swap R042 (1.8K) with R046. Place a 3.9k (from OSD RGB) or 2.2k (from R048) resistor into R042 and a place a diode too. You can use either the SCART connector or an external switch for RGB blanking.

FYI, this clamper circuit only works with no sync RGB. If the signals had sync for some reason than this method wouldn't work and you'd need a different setup
https://www.maximintegrated.com/en/desi ... /3303.html
Last edited by Ryeno on Wed Jan 03, 2024 9:48 pm, edited 2 times in total.
Post Reply