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Hi. I picked up a $15 RCA 20" TV off of FB Marketplace the other day with the hopes of RGB modding it. I'm new to RGB modding but things aren't looking good from what I can tell so far. Here's the details.

- RCA ColorTrak Model 20567CP 20 manufactured in 1989
- CTC156C Chassis
- The U1001 Jungle Chip is a 64pin Toshiba TA777 / NTE15035 / NTE1790 / ECG1790 / SK9850. Datasheet
- Here is the link to the schematic
- Here is a more readable SAMS Service Manual for a set that uses similar chips. You'll see that there is no cross reference to the micro processor which leads me to...
- Micro U3100 seems to be a custom RCA chip I can find no datasheet on. Same with the AIU (Analog Interface Unit) chip U3300

From what I can tell, there doesn't appear to be an RGB connection between any two chips. There is an RGB out on the the Jungle chip of course, but no RGB in. There are picture adjustment controls and a single "OSD CONTROL" signal but that is it. The latter is an output from the Jungle chip to the AIU. Also, the OSD seems to be driven off the AIU: look at Page 10 of the schematic PDF where the OSD Drive signal to the neck board materializes.

I'm hoping someone more experienced in this stuff can spot something I'm missing.

BTW, all the TV has for inputs is coax, composite video, and audio L/R. It would be a shame if I couldn't do anything with it because the TV seems to be in great shape otherwise.

No RGB in so I doubt it's going to work, or if it is possible, it will probably be quite difficult. I'd just keep it as a composite TV and use it that way.

That's almost certainly digital RGB. Analog RGB generally requires a coupling cap. Meanwhile, those resistors would give you about 1.8Vpp for the input signal which is typical of a digital RGB input.

I was afraid but not surprised that you would say this. Oh well, I only paid $15 for the set so no big loss. Thanks for getting back to me.

Thanks for the reply and the explanation on how you knew. I guess I’ll just add an svideo port and use the y/c cores on my mister.

Providing an update as I made some progress just moments ago. Having reviewed all possible I2C settings, I concluded that somehow I must not be getting proper Composite Signal at the (pin 42) External Composite IN pin. As I started removing my wires/barnacles I discovered that somewhere along the progression of modding and migrating parts out to a breadboard so that I could probe with a scope, I had messed up the termination.

Signal --->100 ohm--->2.2ufCAP --->(75 ohm to GND)-->PIN 42

vs

Signal --->(75 ohm to GND)-->100 ohm-->2.2ufCap-->PIN42

I can now see the incoming composite, when selecting AUX input.
(tested with composite from a VCR, and then from an arduino)...

... Now to start on the RGB mod ....

OK so I have a Philips TS2774-C101 (F8 chassis). It should be a candidate for RGB mux mod, with a SAA5565 micro controller and a TDA8844 jungle IC. I have done a mux mod already on a well-documented Sony, so I am not a complete noob, but pretty close...

Here are the relevant portions (mostly) of the schematic. Power for blanking comes from elsewhere on the board (not pictured, but I know where it is).


https://ibb.co/R26Lmgd

The caps at 2625-2628 are 390 pF.
The resistors at 3675-3677 are 150 ohm. (3674 is marked 1800 ohm.)
At 6602 there is a 1N4148 diode, but I guess nothing at 6603-6605.
The properties of the components closer to the jungle IC are marked on the schematic...

I tried to follow MarkOZLAD's stuff, especially his recommendations regarding another Philips (an very similar E8 chassis). I just don't want to destroy this TV.

I think I need to insert somewhere between the 660X spots and the 47 nF caps (2247-2249) heading into the jungle IC.

I am just confused about what other components need to be removed or changed.

Any help would be very much appreciated!

EDIT:
Another thing I noticed studying the board... you see "Ext1R", "Ext2G" and "Ext2B" lines also running to the jungle IC from somewhere else. Somewhere being "A15" which I don't see anywhere in the service manual. So I looked at the board itself, they seem to originate at an unused 5 pin J219 header (R, G, B, blank and gnd). I'd like to piggyback off of that if possible. The weird thing is on the schematic these RGB lines run through resistors at 3231-3233. The schematic says they are 100R, the parts list in the same document says they are zero-ohm (jumpers basically), and in reality there is nothing there on the board. There is no continuity through the pads for 3231-3233.

I wonder if I can put 100 ohm resistors in there as shown in the schematic (which would effectively be my inline resistors for injected RGB), then based on MarkOZLAD's table I would put 680 ohm resistors and 1N4148 diodes in at 6603-6605? Or just 1100 ohm resistors at those points without diodes?

I'm trying to mod a Sony KV-27S42 with a BA-4D chassis from Nov 2000.

I removed R086, 087, 088.
I removed R025, 026, 027.
I added 2.4K Ohm resistors and 1N4148 diodes where R025, 026, and 027 were.

I connected my RGB lines terminated with 75 Ohm resistors to ground at a SCART connector, through 430 Ohm resistors, to the cathode of the diodes (the end closest to the jungle chip).

I connected Sync to the Y pin of the Svideo jack.

I connected all grounds together on the Scart connector and connected that to ground on the Svideo jack

I used 5v from pin 27 of the micro controller and attached it to a switch for blanking.
I put a 1k Ohm resistor on the anode of D003 and attached it to the switch with 5v.

Problems:
1. Blanking with the 1k Ohm resistor doesn't work. If I remove the resistor, it works. Thoughts?
2. The picture is too...strong? Individual horizontal lines are shifted right as if blooming, there's horizontal bands of dark and light areas. It's as if it's peaking or "overloaded".
3. There's interference. I've somewhat remedied this by using shorter wires.

I redid pretty much everything following the instructions here: https://crtdatabase.com/crts/sony/sony-kv-27s42 and now it looks great.

I put the original R025, 026, 027 back.
Then I made my RGB connections with 820 Ohm and 75 Ohm resistors the way a previous poster did like this: https://i.imgur.com/5hiwuus.jpeg

I decided to try that method of putting all the resistors as close as possible to the jungle chip rather than at the connector because to me it seemed like running the original signal through the length of wire from the connector would be less succeptable to interference. Not sure if that's true or not, but I have no interference.

I also moved blanking with the 1k resistor to the other side of the diode and it worked.

I still have to connect audio and make final connections for the switch, horizontal adjustment, etc. but I'm just happy it looks good. I'm debating doing the component mod while I've got it apart.

Since this tv only has one input for both s-video and composite, does anyone know if there's a way to connect both at the same time and maybe do a manual override for s-video, basically disable the "use s-video if an s-video cable is plugged in" feature? I suppose I could get a composite to svideo adapter.

Hey, glad you like the mod guide! The mod seems to function fine without diodes and is much less work that way.

I put the mux resistors on the SCART connector because it's cleaner that way and easier to solder, but there is indeed a greater chance of getting interference if the wires are too long. I've never had problems with it but I do try to keep my wiring as short as possible.



The component mod works well, whether or not it's worth the trouble depends on if you have consoles that require it. Picture quality is pretty much the same with both mods.



Yes, you can do that. Just have to cut the trace running from the S-video detect pin and install a manual switch. The only issue would be the shared audio.

It's also possible to install a second A/V input (composite only). If you peel off the black sticker from the AV ports you'll see that there's already a set of holes in the case for another set of RCA jacks. IIRC most (if not all) the components are populated on the PCB and it just requires the RCA connectors themselves. The extra input can be enabled by changing option setting in the service menu.

Thanks for the info and suggestions. It looks like the missing rear composite input is V3 (V2 being the missing front) and would be J202. I was hesitating doing this because I didn't want to trace down missing components but maybe it's worth looking into it.

I tried using my new scart connector for s-video but with red and chroma sharing a pin I would either have to switch it or lose a 75ohm resistor (since chroma is already terminated which throws off the symmetry of the circuit...but that really shouldn't be a concern lol.) Plus it would mean running my svideo stuff through my scart switch which wouldn't be ideal.

I was able to add a connector to J202 and change ID-1 from 145 to 155 (basically making it a KV-27S46) and that's it. Video 2 is an option now and I've got composite and stereo audio. It's crazy the way manufacturers will hit a price point by cutting features rather than actual expenses.

I finished up the rgb and component mods.

I have one problem. Basically since the inputs are shared certain devices will effect others, even when off.

For example, I have the audio for scart, component, and svideo all just tied together. If I connect my ps2 over component at the same time as my Saturn over scart, the audio is really low.

Similarly if I have my Dreamcast VGA box connected to svideo, it brings down the brightness of the component input.

Almost everything is on a switch that I can turn off all inputs so it's not a functional problem, (except my component switch brings audio down even with nothing else connected to it) but it feels like maybe there's a better way to tie these things together. Or maybe I just need to add audio to a switch too.

I got the wiring done of this Philips. I relied heavily on MarkOZLAD's recommendations (thank you!) for the E8 chassis here:
https://shmups.system11.org/viewtopic.php?f=6&t=69578&start=37

Steps:
1. Remove surface mounted resistors at 3675, 3676 and 3677.
2. At 6603, 6604 and 6605 insert 680R resistor and then a 1N4148 diode on each of these RGB lines. (Resistor closest to micon, then the diode pointed away from micon toward the jungle.)
3. Leverage the unused J209 header. 5 pin header for R,G,B, blanking and ground (pins 1 through 5, respectively). We will use this to feed in our external RGB and blanking. You need to put the pins in yourself, .1" 5 pin.
4. The F8 schematic is odd. It shows 100Rs at 3231 (red), 3232 (green) and 3233 (blue) coming out of the header. Elsewhere in the same document it lists zero-ohm resistors in those spots. On my actual PCB, there were no components there at all. They were all gaps that needed to be bridged. So I bridged the gaps to complete the lines from the header pins to the jungle. I put 270Rs on each of these lines.
5. For the external RGB lines to feed to the appropriate header pins, do the usual where you have your color lines basically branching, one branch going straight to the correct pin, the other branch connecting to ground through a 75R.
6. For blanking, I took ~3V from the leg of a capacitor I believe is 2600 (a 22uF cap), to a switch, through a 75R and to pin 4 on J209. You can probably find a better spot to connect than that pin, it works for my design though.
7. For sync I just fed sync into the composite video input.

This works... I haven't buttoned it all up nicely and haven't even tested RGB simultaneously, but I tested each color. Fairly confident the wiring I described above will not change. I am waiting for a couple more parts before I am 100% finished.

R https://ibb.co/zHdC1ZX
G https://ibb.co/MMr1Hq5
B https://ibb.co/3pPyh0f

Looks like it is not (at least not all of the chassis). It looks like the electrical power goes through isolation transformers. On the board itself, you will usually see a large printed white border, with one side labelled "HOT" (about 25% of the board) and the other side labelled "COLD". On your diagram, the lower left section which is surrounded by a black line with the hash markings is the hot portion of your board.

Yeah, this is a problem. I think the only way to deal with it is to put a manual switch on the luma and audio signals so they don't interfere with each other.

My next project is to do one of these mods using this 6P3T switch. Theoretically it should work!

https://www.amazon.com/dp/B07JM1NK1V?psc=1&ref=ppx_yo2ov_dt_b_product_details

Although there's probably a more elegant solution that doesn't depend on a physical switch. It would benefit plenty of other TV mods too.



Yup, how crazy is that? A 50 cent connector is the only difference here!

That spot is also a great place for a set of component input jacks if you're doing a component mod.

I used a 4P3T rotary switch but never ended up using two of the poles. I don't need to switch svideo enable with the second composite input, and I tested a bunch of stuff and didn't think the horizontal position switching was necessary (though I may still do that as a separate toggle).

I think when I feel like taking it apart again I'll add left and right audio to the other two poles and redo the chroma switching and actually switch the svideo jack's input.

For now I just gotta remember to only have one input active at a time.

Cordial saludo para todos.

I got a "new" set in an unopened box, I found it in a warehouse that was closed since before the year 2000. The chassis is CTC177AH which in general is the same as the one you are modifying.

Following on from the conversation you had for your chassis, I want some guidance on modifying my set. I have prepared a schematic of what I understood to make the mod and I drew a trace of the TV circuits to verify that it is the same as the one you modified.

I appreciate any help you can give me to get to the happy modification of my set.

instead of 1000 resistor my set uses 3000 resistor and instead of 120 resistor my set uses 360 resistor

Hi all,

I've just bought a Sony KV-21SE40A, (it's a PAL model). I've been doing some research, as to what needs to be done to mod this model, since it has a BA-4 chassis and a CXA2061S jungle chip. Now, I'd like some help to calculate the right values of resistors (I have made a copy of OSD Mux RGB Calculator on Google Sheets) and if possible, a step-by-step guide (as I'm unsure if it's safe to follow a guide for BA-4D).

thanks!

I have a Trinitron KV-32S15 which has a CXA1465AS jungle chip on a separate board, perfect for RGB, taking in an analog RGB signal from the Closed Caption IC (no datasheet available). Because the OSD menu is fed into separate digital RGB lines, I don't need to worry about a mux mod (who cares about CC?).

The issue is that the resistor and capacitor values going into the RGB lines are funky. I would expect to see 0.1 uF capacitors in series and 75 ohm pull down resistors going to ground.

Instead, I see 10 uF capacitors and 1K pulldown resistors.

The datasheet only has 220 ohm resistors in series followed by 10 uF capacitors.

What should I do? The analog inputs need to be 0.7 Vpp, as usual, but should I be using ONLY my own 0.1 uF capacitors and 75 ohm resistor, or just THEIR 10 uF caps and 1K resistors -- OR both theirs AND mine ???

ALSO: Is it okay to directly tie the blanking line to 5V high coming off the regulator without adding any resistor, or do I need to worry about limiting the current?

if you're sure the inputs are meant to take 700mVpp with no bias, then just use your own 75R termination and 0.1uf coupling caps only and disconnect everything that was there before

I'd always recommend a current limiting pullup for blanking, but it's usually not required strictly speaking

Picked up a Sharp 13VT-N100 for free recently as I wanted something appropriate to connect retro consoles up to.
I hope to do the "Mux" RGB mod on it by ordering a kit from Sunthar https://sector.sunthar.com/nav.03.Store//, but I am very new to this and would like some pointers.
I've found the service manual for the TV here https://www.manualslib.com/products/Sharp-13vt-N100-3540166.html and from there I found out it has an IX3253CE jungle chip which judging by other posts on this thread is a clone of the Toshiba TA1268N.
https://i.imgur.com/cwDWmic.png

I'm not too worried about what happens to the set in the off chance it quits working, but if anything, where should I go from here?

I had the mod working on a breadboard (with 2.5V going into the blanking) -- it was beautiful!!! and then I fried it putting everything back together on perf board. I am not sure what happened but I suspect I accidentally sent 5VDC (or worse -- -5VDC) into the RGB lines. Now the blanking pin works fine, but I can't pass in R, G, or B signals anymore -- it's always stuck at a black screen. Is there anything I can do? I ordered a replacement jungle chip and will swap it in. Luckily the only thing going into those RGB lines was the mod, not the OSD, so that limited the possible damage. Sigh.

EDIT: It was likely ESD damage

Hello,
can i ask if the brightness is very low how can it be adjusted as from the tv menu the settings are not available for RGB signal?
I use this cable for PS1/PS2 and the picture is very dark.

Hello.

I have a KV-27S45 BA-4 chassis. Is it the same process as the BA-4D RGB mod? https://github.com/brendanseattle/SonyR ... /README.md

Is it possible to have component inputs too?

I’ve got a Sony KV-32S45 that i RGB modded following this guide: https://imgur.com/gallery/86MwRVT

It’s working mostly alright, but i’ve got 2 issues:

1: there’s an arc that curves left on the left side of the screen that is always there, even on standard input, that is just a minor fluctuation in the brightness. It doesn’t change brightness or move, but is noticeable on dark images like the beginning of Super Metroid.

2: only on RGB input, there’s a moving horizontal ripple in areas of dark contrast. I first noticed in in animal crossing running around the forest with blinking holiday lights. And I’ve been able to consistently identify it in Banjo-kazooie in dark hallways in grunt’s lair. It’s not always noticeable, but it is distracting when you see it in motion. I’ve tried shielding my cables and moving my switch in case it was being affected by EMI from the tube, but it doesn’t seem to have done it. What am I missing?

Good evening/afternoon/morning, it's been a long time since I was on here last.

I got my Sony PVM-9L1 modified with RGB successfully back in January 2022 and it looks amazing.

I have another set I would love to add RGB and s-video to it, the Orion TVCR0950B and the jungle chip under the VCR portion is a Toshiba TA8801CN, and I'm not sure if the Orion OCE9030C is the microcontroller or some other chip since the Internet shows nothing for that chip.

In any event, is it possible to add RGB and S-video to this unit? The only datasheet I see is the one for the TA8801AN and I believe the CN is similar to the AN chip, but I digress. I also watch TV on it with my DTV box and a POS universal remote that has missing functions (I ordered a new remote for the set) and cleaned the set since it had too much dust internally and externally.

Also, I ordered a service manual for the unit so I can look at the chips on there to see if the CN is the actual jungle chip and determine the OCE9030C chip to see whether it's a microcontroller or something else with schematics for which pin goes where between the two chips anf go from there.

I believe the same modding instructions for the BA-4D will apply to the BA-4. It is possible to have both Component and RGB if you use a 3P3T switch like I did to my set.

https://imgur.com/a/TFw7VLg

On the 27S models, you'll likely have a small switch inside the set for controlling horizontal position. You can use a 4P3T switch and use the fourth pole to change the horizontal position accordingly if you wish to do so.

https://crtdatabase.com/crts/sony/sony-kv-27s42

Hello, I'm very new to this so forgive me of any ignorance. I got ahold of an RCA F27676BC (Chassis: CTC187AJ) recently and am eager to do my first RGB mod on it. I was able to get ahold of this SAMS Service Manual for it. It's a different model by 'YX1' at the end, but it's the same Jungle Chip [LA7610]. I created a stitched image of the RCA motherboard to compare to the Service Manual, this is where my ignorance is at and feel like I'm doing something incorrect. The connection of those 1500 Ohm resistors (colored yellow) shared by the input of the transistor in each RGB line is what is tripping me up. It leads to pin 47; chroma kill, should I be ignoring this? In my head, these have an affect on the flow of electricity, so I should find all the component values in that line, no?
plz reassure me

Hi all,

I'm having some weird video issues on a Sony KV-21SE40A where I did an RGB Mod following this guide https://sector.sunthar.com/nav.01.Guide ... rt-rgb-mod (mine being a BA-4 chassis but the board looks very similar)
I don't understand why the sync is not working as expected (I'm using the Mister FPGA with composite_sync enabled). Any ideas or suggestions are very much appreciated.