Need help with composite video from PC Engine GT

Started by grahf, July 21, 2006, 03:18:42 AM

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I really hate to have to post this, but im really in over my head on this project. I have been trying to trace composite out from my PC Engine GT for the last few weeks. I have a modern LCD i plan on installing, but its only composite input. Its all been a learning experience for me, as i have no prior knowledge with video applications. On the wiki, there is information on this page:
However there is more to it than that. Pin 30 seems to go into a transistor. I know when people add AV to NES, they use a transistor to route in extra power to the circuit. Maybe its the same here? Also, there appears to be a bank of small resistors that the line may be going through, but i cant tell due to the coating on the board.

Here is what i figured out so far:

I cant find any markings on the transistor, or even its function (besides my guess about the NES AV). Any insight would be most apreciated. I DONT want somebody to do this for me, but i need a bump in the right direction.

Thanks guys.


Your best bet is to check out the circuit on a larger, un-coated version of the hardware.  A TG16 (PAL or NTSC) would be best, or a Vistar if you've got one (heh).  They're more likely to have circuits you can see, and transistors that are properly labelled.

I never did map out the video circuits when I was making my PCE schematics, it was such a pain in the ass, and I didn't really think it was important.  Sorry.  =)


I went ahead and ordered a broken TG16 to take a look at. I already tried looking over my Duo-R, but i wasnt able to find any ascertainable markings. With the broken TG16 i wont have to worry about pulling things apart.