KV-9PT50 S-Video mod using various resources from SegaSonicFan and Reddit posts.

Started by Grubbens, February 08, 2023, 08:31:02 AM

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I am restoring this Sony KV-9PT50 and I decided to add a little S-Video mod to improve the picture a little bit get some practice working with CRTs/ circuits, but I am having trouble with distortion in the picture. I will include a Reddit post I made earlier for some context.

Below is a post I made to reddit's /r/crtgaming subreddit:


So this is the current issue that I'm having. I did an s-video mod on this CRT and I had everything with a very high quality picture (no distortions), but it was in black and white. I opened it up and reflowed the solder to the chroma pin in on the jungle chip and BOOM! I got color, but the picture now looks like what you are seeing.

My S-video jack chroma pin has a 1uf cap going in and a 75 ohm resistor to ground. Luma is coming from my composite video center pin with no resistance to ground.

I have everything hooked up to a switch for composite and svideo, with composite working nicely.

Any thoughts on this? It's a bit troublesome after all this toiling, so I hope to get it to work! I have been teaching myself how to do this all weekend and I have learned a lot!


I have since added a 75ohm resistor to Luma ground and shield, the picture is dimmer and more distorted.