Just to clarify, with no HuCard game inserted you don't even get to the CD System Menu screen?
Yep. I tried every possible combination (no game in the system, HuCard only, CD-ROM only, and both HuCard and CD), and I get the static colored screen no matter what.
Thanks for your suggestions. The first thing I tried when I noticed the problem was cleaning the slot and cards with alcohol. I just did the slot a second time more thoroughly by removing the shield, and it didn't change anything. I also tried slightly pulling the HuCards before turning on the console, no dice either.
Are there any signs of modification to the cartridge slot? I'd lift the two screws on the slot shield and take a look. It very well could just use a thorough cleaning.
I didn't notice anything odd, but seeing as this is my first DUO, I can't say for sure. It was purchased on Yahoo Auctions Japan, so I guess if the only purpose of modding the slot is playing games from another region, the chances of it being modded are pretty slim.
Upon further inspection, I think there
might be a leaking capacitor. According to the cap replacement chart, that would be leftmost 22uF capacitor. I'll see if I can post a picture of it and one of the whole board tomorrow. Would that single capacitor really affect the unit like that though?
If that's really what the problem is, I'll have to choose between trying my hands at soldering a circuit board for the first time (and hope that capacitor is the only one that's failing, because I sure as hell won't replace every one of them), or browse the boards to see who offers good repairing services.
Is there anything else I should try out before that? How likely is it that a different component is failing, not the capacitors?
Thanks for the help so far!