Hitachi CPT-1455 RGB mod

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Hi,

I've got a Hitachi CPT-1455 (NP84CQ/2 chassis) that I am considering doing an RGB mod on, and because this is a hot chassis I plan to use optocouplers like the HCPL-4562.

It's unfortunately an RF only set, but the picture quality and geometry is pretty good, and it has low hours so it's worth modding in my opinion. I also love the form factor and look of it.

The main IC is a TDA3562A and according to the datasheet it supports RGB input at 0,9-3V. I had a look at the brother CPT-1444, and it's got native RGB input according to the service manual. Here is a screenshot of it:



These TVs have the same chassis number, but obviously different revisions and power supplies. Here is the service manual for my CPT-1455, I had to buy it on eBay, scan it and upload to this site.

So my idea was to wire up the RGB inputs using high bandwidth optocouplers for analog video, powered by an isolated 5V power supply at the input side, and add a SCART connection to it.

There is a thread here showing a evaluation board that shows how to wire up the optocoupler for analog video/audio: https://antiqueradios.com/forums/viewtopic.php?t=430210

However I'm kind of stuck on how I should go about wiring this. So far I'm on the edge of buying a set of PCBs and optocouplers and just try my best using regular RGB mod guides, but do I need any extra circuit on the TV side? If I use the CPT-1444 board for reference, there's a lot of added circuit handling the RGB signal. I believe it's not as easy as just inserting the RGB signal straight to the IC with some 75 ohm resistors to ground and enable the blanking, is it?

As of now I've built in a composite to RF converter into the TV with its own isolated 5V power supply, so the TV works like a proper composite set, and the picture is pretty good, but having native RGB would be perfect.