TV RGB mod thread

goldendark007 · Joined: 31 Dec 2013 Posts: 20 Location: New York

Hey - so I am ordering the 6pin connectors and I wanted to know if there was any suggestions on max or min wire gauges etc.

Thanks! Once everything arrive I will try to make a video and post progress. Thanks again for all the help. You are all so damn wonderful!

MarkOZLAD · Joined: 18 May 2017 Posts: 657

metrodigital wrote:

Hi Guys,

I have the opportunity to buy a Sony Trinitron KV-XA25M30A CRT TV, and I want to RGB mod it for use in an arcade.
Would it be a good model to mod?
I'm very new to how this all works, but don't want to miss the opportunity of picking up a good TV that is also the right size for my use.

Here is the link to the TV Service Manual:
https://we.tl/t-KlEZldumJZ

Thanks

That set can be RGB modded but have you considered using an RGB to Component adapter?

Something like this - JROK RGB to TV Adapter

It is also a flat screen so not really authentic arcade. It would work though.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

Hey guys, me and a friend we succesfully RGB modded my Sony KV-27EXR25 TV via the ugly switch method, and it works! But I want to do this the right way. We havent snipped anything yet, so the mod we did is totally reversible. I think I have all figured out (I will post the version of the Mux diagram for my TV soon), but I am searching for the necessary components. I think I read about resistors watt rating in other post here, but I cant find it right now, so do you guys recommend any one in particular? 1/8, 1/4w?
Thanks a lot!

Nevermind, found it! Thanks a lot. I will post the diagram as soon as I have all figured out.

Quote:

1/8th watt are fine

tolerance does kinda matter, get 1% or better they are cheap enough to not bother with anything less

digitron · Joined: 10 Apr 2019 Posts: 53

MarkOZLAD wrote:

digitron wrote:

I would've never guessed you could put a resistor between the signal and ground like that!

It definitely is a concept people struggle with at first, me included. That's the "75 Ohm Termination".

Mark, sorry for the dumb question but does it matter where I ground the RCA connectors? Any ideas about where to ground? I'm not sure if it matters or not, thx.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

digitron wrote:

Mark, sorry for the dumb question but does it matter where I ground the RCA connectors? Any ideas about where to ground? I'm not sure if it matters or not, thx.

Doesn’t matter too much where you ground it. The Tuner shield, heat sinks, where heat sinks attach the chassis, empty ground holes from components that aren’t installed in your version of the TV. A million places.

Look for something nearby. A good test is to put the multimeter on ohms or continuity and put the black probe on the RF Tuner shield and the red probe on a place you think might be ground. If there’s 0 ohms resistance you have found a ground.

Ground plains are also fairly easy to spot on the printed circuit board after a little practice.

digitron · Joined: 10 Apr 2019 Posts: 53

MarkOZLAD wrote:

digitron wrote:

Mark, sorry for the dumb question but does it matter where I ground the RCA connectors? Any ideas about where to ground? I'm not sure if it matters or not, thx.

Doesn’t matter too much where you ground it. The Tuner shield, heat sinks, where heat sinks attach the chassis, empty ground holes from components that aren’t installed in your version of the TV. A million places.

Look for something nearby. A good test is to put the multimeter on ohms or continuity and put the black probe on the RF Tuner shield and the red probe on a place you think might be ground. If there’s 0 ohms resistance you have found a ground.

Ground plains are also fairly easy to spot on the printed circuit board after a little practice.

Perfect, thanks again

MikeIronFist · Joined: 31 May 2019 Posts: 4

MikeIronFist wrote:

Hey y'all, I've got a KV-27S42 so I hoped you guys might have a good idea of how to properly do the OSD Mux-via-resistors mod.
I've already done the switch-based mod on this set with 75 ohm termination and the end result was great. I didn't have to lift the legs on any of the chips, I just removed C316, C317 and C318 (the caps connecting the jungle to the OSD) and I put 0.1 uf caps on new wires to the jungle IC's RGB and BLK inputs.

I stripped and soldered some Du Pont wires for every connection so I could easily reverse or change the new setup. So, once I know exactly what I need, I can basically just make drop-in replacement wires to connect to the board and SCART socket. The one thing that's tripping me up is what to do with the OSD blanking. Seems like it merges with the O-YM line and goes into a 10k ohm resistor (R004) to chassis ground.

Here's an image of the OSD chip and Jungle taken straight from the service manual. OSD blanking line is highlighted in orange:

Spoiler: show

So if I understand the resistor table correctly, I need at least 837 ohms of resistance on each of the RGB lines since the in-line OSD resistors are 5.6k. But what am I doing with the OSD blanking line in terms of resistors? Am I adding a 10k resistor to the external blanking? Am I also removing the 10k resistor that connects the original line to chassis ground? I'm just a little uncertain if I'm following the diagram correctly and want to be sure.

EDIT: never mind, in my infinite clumsiness or incompetence I seem to have killed my KV-27S42. Something, somewhere shorted or overloaded (there's no busted/leaking caps but who knows if one died) and now it turns on to a black screen for a bit, suddenly turns 100% white and then the white image slowly collapses and it automatically turns itself off. RIP :cry:

Original Post:

Spoiler: show

digitron · Joined: 10 Apr 2019 Posts: 53

MarkOZLAD wrote:

digitron wrote:

Mark, sorry for the dumb question but does it matter where I ground the RCA connectors? Any ideas about where to ground? I'm not sure if it matters or not, thx.

Doesn’t matter too much where you ground it. The Tuner shield, heat sinks, where heat sinks attach the chassis, empty ground holes from components that aren’t installed in your version of the TV. A million places.

Look for something nearby. A good test is to put the multimeter on ohms or continuity and put the black probe on the RF Tuner shield and the red probe on a place you think might be ground. If there’s 0 ohms resistance you have found a ground.

Ground plains are also fairly easy to spot on the printed circuit board after a little practice.

WOOHOOO!!!

Mark!!

Welcome to the Jungle Baby!!!

Fired up first try, I'm freaking stoked man. Thanks again for walking me through this. Couldn't have done it without ya!!!!

Got the image centered! Make sure you use standard user modes (not super), looks great!

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

Alrighty guys, here are the schematics for my TV, Sony Trinitron KV-27EXR25. As I said in my previous post, we had success with the obsolete method, and now we want to try to do with the MUX method.

Jungle:

Full image:

Spoiler: show

OSD:

Full image:

Spoiler: show

Hopefully I got to link the images correctly :roll:

So, this is what I think we should be doing. Please, check if it looks OK. I don't entirely get what resistors I have to remove, "factory voltage divider resistors". It dictates the value of the resistor in the new RGB blanking line, right? The new resistors have been calculated using diodes on the OSD side.

Let me know your thoughts!

MarkOZLAD · Joined: 18 May 2017 Posts: 657

I wonder whether pins 10,11 and 12 of CXA1313S are for digital RGB input. The lack of a voltage divider on the OSD RGB lines (thus your question mark on the diagram about removing the factory OSD ground resistors) suggest it's digital RGB only.

I can't find a datasheet for that Jungle chip. I would need that to comment further.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

The datasheet for CXA1465AS mentions the CXA1313S. I note that both of these chips are 48 pin and the CXA1465AS has digital RGB in 10/11/12 with digital blanking in 9.

I'll take an educated guess that the CXA1313S is the same pinout as the CXA1465AS and the Analog RGB inputs are into pins 16/17 and 18 with blanking on 15.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

digitron wrote:

WOOHOOO!!!

Mark!!

Welcome to the Jungle Baby!!!

Fired up first try, I'm freaking stoked man. Thanks again for walking me through this. Couldn't have done it without ya!!!!

Love it!

Any pics with the OSD on top of your external RGB?

First try? Where's the fun in that? :-)

MarkOZLAD · Joined: 18 May 2017 Posts: 657

MikeIronFist wrote:

EDIT:[/b] never mind, in my infinite clumsiness or incompetence I seem to have killed my KV-27S42. Something, somewhere shorted or overloaded (there's no busted/leaking caps but who knows if one died) and now it turns on to a black screen for a bit, suddenly turns 100% white and then the white image slowly collapses and it automatically turns itself off. RIP :cry:

If you haven't busted one you're not trying. I have busted my share.

Sorry if we missed your post at some stage, because of the approval lag they don't show up in order and get missed.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

MarkOZLAD wrote:

The datasheet for CXA1465AS mentions the CXA1313S. I note that both of these chips are 48 pin and the CXA1465AS has digital RGB in 10/11/12 with digital blanking in 9.

I'll take an educated guess that the CXA1313S is the same pinout as the CXA1465AS and the Analog RGB inputs are into pins 16/17 and 18 with blanking on 15.

Thanks for your help Mark
This is the result from my first mod approach (the old way) using pins 10, 11 and 12 for RGB
As you can see, almost anything that isn't R, G or B is black, or very dark. Could this be because the pins I used are for digital RGB, as you said?

In spoiler, a few pics of some better results, same pins used.

Spoiler: show

I thought that this color problem was caused for a bad setting in the Picture menu of the TV, but this particular Sony model has no menu, it uses the RM-Y104 remote, which I don't have, that uses its own two buttons to navigate the picture modes and settings. So I never got to try if that was the cause, but now I think that what you said could probably be causing this.
If any of you guys have one for sell, please let me know!

EDIT: I didn't find any schematics for the CXA1313S, but I did find one for the CXA1465AS, as you mentioned. I think this part is relevant to my case, isn't it? Sadly I dont fully understand all what it means

MikeIronFist · Joined: 31 May 2019 Posts: 4

MarkOZLAD wrote:

MikeIronFist wrote:

EDIT: never mind, in my infinite clumsiness or incompetence I seem to have killed my KV-27S42. Something, somewhere shorted or overloaded (there's no busted/leaking caps but who knows if one died) and now it turns on to a black screen for a bit, suddenly turns 100% white and then the white image slowly collapses and it automatically turns itself off. RIP :cry:

If you haven't busted one you're not trying. I have busted my share.

Sorry if we missed your post at some stage, because of the approval lag they don't show up in order and get missed.

It's all good Mark, I appreciate the consolation. The references and info you've posted have helped me plenty too.

I'm looking at buying a kv-20ts32 now and it has an analog RGB in from the closed captioning board; gonna report back if I manage to snag it.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

Kabal2X

Your mod looks way better than I would’ve expected.

Try turning up the screen voltage. There is usually a pot on the flyback.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

I would have to check again, but if I remember correctly, there was only a Focus pot on the flyback. Thanks for your help Mark, hopefully is something simple!

digitron · Joined: 10 Apr 2019 Posts: 53

MarkOZLAD wrote:

digitron wrote:

WOOHOOO!!!

Mark!!

Welcome to the Jungle Baby!!!

Fired up first try, I'm freaking stoked man. Thanks again for walking me through this. Couldn't have done it without ya!!!!

Love it!

Any pics with the OSD on top of your external RGB?

First try? Where's the fun in that? :-)

Right??

I'll get a pic of the OSD over RGB this weekend when I get back home.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

Kabal2X wrote:

I would have to check again, but if I remember correctly, there was only a Focus pot on the flyback. Thanks for your help Mark, hopefully is something simple!

There will be a screen pot somewhere. Check the Sams photofact.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

MarkOZLAD wrote:

Kabal2X wrote:

I would have to check again, but if I remember correctly, there was only a Focus pot on the flyback. Thanks for your help Mark, hopefully is something simple!

There will be a screen pot somewhere. Check the Sams photofact.

Thanks Mark, I found the G2 pot in the neckboard, I gave it a little more screen but no change in my RGB mod picture. Also, I tried using the service mode to change color and brightness, but no big change, even with brightness at max. I then tried with my Sega Saturn using composite video and screen is way too high, so the pot is good haha.

This makes me think that the problem has to do with my RGB pins used, what do you think Mark?

Thanks again!

MarkOZLAD · Joined: 18 May 2017 Posts: 657

Kabal2X wrote:

This makes me think that the problem has to do with my RGB pins used, what do you think Mark?

Yeah, I think they are wrong.

Seeing as you already have a heap of the wiring in place, might be worth implementing the OSD snip method (I must be feeling ill..) on the analog RGB lines instead. I believe they are being used on the Picture in Picture circuit.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

Haha I will try to it in a reversible way! Thanks Mark, will let you know how it goes.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

I guess you don’t really need PIP so you could just disconnect it and inject your external RGB there. Mod done.

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

Ok I will study the schematics tomorrow for these points.

I had the idea today that maybe it was caused because the cable I was using was badly soldered somewhere. (Im using Raspberry Pi + VGA666, tried and tested before on arcade monitors), built a new cable, no change. Also tried with my Sega Saturn + cheap ebay SCART cable, but I think its just composite video, after comparing with thw regular composite cable picture, so its no good for our problem. I will check tomorrow using RGB from my Megadrive 2, to try and reproduce the brightness problem. Once again, thanks for your help and patience!

Yulius · Joined: 05 Jun 2019 Posts: 5

hi, im new in this forum and im learning how to do Tv crt RGB mod by osd mux.
actually i mod 2 sony BA-4D chassis and 1 and AA-2D (and work nice).

now i try to do osd mux on daewo tv, i used same metod but result in too dark image (all colors are obscured and osd letters are black now).
i need help with this tv please, i adjunt the schquematics i use on this tv.
(sorry for my english).

https://ibb.co/MV8CWNs
https://ibb.co/H2kQcfs
https://ibb.co/Wxzk604
https://ibb.co/ykmygYj
https://ibb.co/Xy96VVG
https://ibb.co/QDg41Xw

Syntax · Joined: 09 Aug 2017 Posts: 1379 Location: Australia

Kinda looks like you put the wrong voltage to blanking and its going into Half-tone.

I may of missed something but why are you not using 16 17 18?

Kabal2X · Joined: 16 Mar 2012 Posts: 30 Location: Chile

Syntax wrote:

Kinda looks like you put the wrong voltage to blanking and its going into Half-tone.

Hmm I'm using 5v to blanking, pin 9 of CXA1313S. The diagram says .1v, does this means its actually expecting 0.1v? Thanks Syntax, I have a feeling this may be the problem. Is there a way to know how much voltage I need to put there?

Syntax · Joined: 09 Aug 2017 Posts: 1379 Location: Australia

Kabal2X wrote:

Syntax wrote:

Kinda looks like you put the wrong voltage to blanking and its going into Half-tone.

Hmm I'm using 5v to blanking, pin 9 of CXA1313S. The diagram says .1v, does this means its actually expecting 0.1v? Thanks Syntax, I have a feeling this may be the problem. Is there a way to know how much voltage I need to put there?

For blanking you need 5v going through a 180R resistor then a 75R termination to ground before the blanking pin normally.

But from the document you posted it seems you are bypassing the brightness control and clamping of the jungle by not using pins 16 17 18. Could be the issue. Blanking seems to be Ys which is pin 15

MikeIronFist · Joined: 31 May 2019 Posts: 4

Kabal, just wanted to add: I've seen colors in my OSD get weird and blocky like that when I change the "DRGB" setting in the service menu to 1, which presumably enables digital RGB. So it might seem silly to try this, but see if there's a DRGB item in your service menu and see if you can set it to 0. This is total guesswork but since I've seen IC switchable digital RGB once already, I think it might be worth checking before you do any more soldering. If it's not changeable in the service menu then you can still try the other pins (16, 17, 18) as recommended and see what you get.

MarkOZLAD · Joined: 18 May 2017 Posts: 657

Yulius wrote:

hi, im new in this forum and im learning how to do Tv crt RGB mod by osd mux.
actually i mod 2 sony BA-4D chassis and 1 and AA-2D (and work nice).

now i try to do osd mux on daewo tv, i used same metod but result in too dark image (all colors are obscured and osd letters are black now).
i need help with this tv please, i adjunt the schquematics i use on this tv.
(sorry for my english).

https://ibb.co/MV8CWNs
https://ibb.co/H2kQcfs
https://ibb.co/Wxzk604
https://ibb.co/ykmygYj
https://ibb.co/Xy96VVG
https://ibb.co/QDg41Xw

I believe your blanking circuit is incorrect.

the datasheet is here..

https://pdf1.alldatasheet.com/datasheet-pdf/view/87309/TOSHIBA/TB1251CN.html

Looks like your set might want 3.3V or more to blank as there is a half tone circuit on your set.

These days on blanking circuits I like to cheat rather than bothering to make scart pin 16 do the blanking. After returning the set to factory blanking, I would just run a 5V line through a switch and then a 620 Ohm resistor onto the leg of RC730 (I think that's what is showing on schematic) that is farthest from the micro controller.

Like this

This way we are just mimicking the way the TV's OSD blanks and you take away any need to do calculations.

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