Need Help with SEGA Nomad Audio/Video Issues

[retroupgrade]

After the first 2 seconds after powering on, my Nomad video is garbled and the audio gets weird. The first 2 seconds show perfect video. This makes me think there is a capacitor acting up. I've replaced all but 5 or so caps, so hopefully it's a matter of time until I get to it.

Has anyone here seen Nomad video output that is torn and loses color until it's black and white? Also, if left alone, the video will eventually cut out entirely and, at that point, the audio goes out, too.

Please help! I'm trying to save my poor Nomad.

[Ziggy587]

I would suggest replacing the rest of the capacitors and then go from there.

What power source are you using?

I recommend moving this thread to the tech help forum.

[retroupgrade]

I'm using the AC adapter that came with the SEGA Nomad which is the same as the Genesis/Megadrive 2.

[Anapan]

I've only ever seen that kinda thing happen when I'd installed a new composite screen that was incompatible with 240P video. The screen kicked back on during Sonic 2's split-screen 480i demo. That probably isn't your problem, but a new back-lit LCD is probably your solution.
I can't offer much here to pinpoint your problem area. It's most likely the power source for your internal screen. In that case, a great solution is to upgrade the screen to a new better backlit LCD. It will be easy and a definit improvement. You'll be rid of the passive matrix ghosting and any other screen problems as you'll bypass the entire section of the circuit board and pull composite off the motherboard much earlier.
You could try plugging a Geneis2 video cable into the top video output to see if this upgrade will fix it. Just plug the Nomad into your favorite screen and see how it fares.
If the output still does the same on an external screen, at least you have narrowed down the affected area of the motherboard to really-close to the main PPU. If the external screen works, the upgrade is a no-brainer - the power consumption alone is a great improvement.