A friend of mine collects old video game consoles, and has a NEC Duo with only a composite output. He wanted a RGB output to plug into his SCART switch, and bought a kit from some French company before he talked me into wiring it up. The kit is a small board and a couple of caps plus a piece of double sided tape, and comes with instructions on an amateur website that I know for a fact is at least partially wrong, for the small sum of around 90$ with shipping (which is ridiculous). I did wire it up as per instructions, but the board quality was horrible (and he paid a small fortune for it!). Every exposed pad for input and output is SMT, copper is super thin, and every pad I tried soldering to ended up lifting in seconds... I did succeed in wiring it by soldering to the onboard through hole caps, and got everything wired nicely inside the casing, but the final result, while it does work and colors do look fine, is full of ghosting to the point where you can't read text on screen. I checked my connections, and added some caps on the output, redid the wiring with twisted pair, but the result is always the same. At this point I think the dubious board is the problem, and I am determined to fix him up a good working replacement. Now I am vaguely aware of what RGB signals look like, but I am wondering if there is any kind of tried and tested RGB amplifier circuit you guys could suggest. TI used to make nice little chips like the LM1203, but they are discontinued and they list no replacement part. A search on digikey for other RGB amplifiers turned out empty. I will be grateful for any leads you could give me... Note that this is not for high-resolution (the console generated 320x240 256 colors AFAIK), but it does need to be able to drive a high resolution LCD. It does not need to be perfect (let's face it it's a 25 years old console), but it needs to be cheap to build, either from discrete components or a chip, small and work properly.
Joined: Fri. Feb 19, 2010
Posts: 729 View posts
Location: Montreal, QC, CA
Last Edited: Fri. Jul 10, 2015 - 05:44 PM