RGB mod a 1983 Sony RV-1952RX (Trinitron)

[GamerMechanic1981]

I pulled this old TV from the trash almost 20 years ago. It has always worked fine. I kept it in my parents extra garage and watched TV while working on project cars before tv went digital. That was before I got into retro gaming.

The folks are getting rid of the extra storage, so I grabbed this old set. I'm hoping there is a way to add component, S-Video, or composite or something as an option since at the moment all it has is RF input.

I have prior experience modding consoles for HDMI using kits I purchased from gametech and am pretty confident with a soldering iron.

Anyway it has chassis number SCC-470H-A. I have a full schematic for this chassis. IC301 is a Sony CX-848 and the RGB circuits trace back to pins 32 (blue), 33 (green), and 34 (red). This chip is listed as being "Y/Chroma" on the schematic.

IC501 is a CX20013A and is listed as being Sync Sep/Horiz/Vert Osc. I may not know much about video signals, but I am aware that sync is important, so it seems that I will need to tap into it somehow. It might be one of the pins on IC501

I can provide pictures of the schematic, but I don't see an easy way to do it in this message board.

Edit: test point 12 is listed as a spot where a color video signal may be injected. Does this mean I can directly connect a composite video signal there?

[freakaftr8]

The IC is most likely labeled the VIF circuit. I have not done this yet but to add composite you would inject the video into the chroma but there might be a delay. You need chroma and Luma. Is there a video-in pin on that ic? That might do the mixing for you. Also you will need to inject audio into the SIF section IC in the audio-in pin there too.

Best way to perform this is to pull up this pin from the board so there is no interference with the tuner. Or cut a trace on the board and inject after the trace. Same with audio.

As for RGB, not advisable. there is too much in the way of Y delay between chroma and luma delays before and after the Y. Possible to inject at neckboard but the.voltages will be different and you would have to inject sync at the Jungle ic which will also cause delay issues.

I heard about s video inject cause that separates chroma and luma and composite. all injected into the IC appropriately. if the schematic shows there these paths are, then try that.. this is all speculation of course. Read about it but never preformed.

It's tough when the set had no OSD.

[GamerMechanic1981]

IC 201(Sony CX885B) is listed as VIF/SIF. Test point 12 is located at pin 41 of this IC and is connected to IC 302 pin 6 through a 100 pf cap. Diag instructions say you can inject a color video signal here but says nothing of Chroma, luma etc. I don't care much about sound injection, because it would be easier to inject those at the input side of the amp. That's relatively easy. It's only got a mono speaker anyway.

[freakaftr8]

Then it would suggest most likely a composite signal be put at pin 41. Now if so, you would probably be best to disable the rf/if into that IC from the tuner first.

[buttersoft]

There's another thread on the first page right now about adding S-video to a Sony Y/C jungle. Might help, if yours is at all similar.