PCE DUO CD-ROM spinning non-stop after recap

[michellybells]

Hello! This is my first post, though I've been a PCE owner for almost a decade now. I picked up a used Duo here recently as a spare, with the goal of recapping it. It worked surprisingly well in its raw state for a few weeks before I started work on it, being able to play CD and game audio for several hours with no issues, but of course eventually the telltale signs of cap wear started to appear. I took it with me to a computer group where a professional electrical engineer friend de-soldered all the SMD caps with a heat gun (and the rest with a Hakko), and we went about putting all the new caps in. Once all the caps were in, the system turned on and HuCards looked and sounded drastically better. The problem however, is that the CD drive now spins non-stop from the moment the system is turned on, regardless of whether or not the CD cover switch is pressed. (I could be wrong, but it also feels slightly faster than normal RPM as well.) If you press Run with a Syscard in, the lens will automatically move all the way to the outer edge of the rails and stay there. You have to manually return it back to the starting position.

So far I've checked all the caps, and they're all the correct values and polarity. All the caps are slightly higher voltage rating than the originals, most of them being 16v. I haven't found and shorts on the board or damaged resistors. That I know of, none of the pots were moved, intentionally or accidentally. The CD drive was working fairly well before the recap, so I don't think the laser itself is damaged, and the cables all seem fine.

Any idea what I should check next? My only though was that possibly one of the BA6290A ICs got heat damage from desoldering, but as I've read in the forums so far, it seems like a bad BA6290A would make it not spin at all, instead of spinning endlessly. Just to be safe, I bought two spares, as well as a new lens, from Hong Kong. I'm thinking I should examine the output of these ICs with a scope, but aside from being new to using a scope, I'm not even sure what a good output I should look like. Any advice?

[Keith Courage]

Look just to the right of the two 47UF capacitors near the CD loading light. There is a big Via hole there that can short out. Make sure it has 5V on both the top and bottom of the board in this area. If it doesn't, scrape off some of the green and solder in a wire or extra capacitor lead to repair.

[michellybells]

Any chance you have a picture of what you mean? I checked the vias in that area, they seem to be normal. I also checked the voltages around there, there's 5v in some places, 4.5 or so in others, and one via (cap to the left of the CD LED had like 3.2v or so. Also, is there a full schematic for the Duo anywhere? Thanks!

[Keith Courage]

Via hole circled in Red. Make sure it has 5V on both sides of the board. I just solder a capacitor lead on each side of the board through this via hole and it usually fixes the immediate CD spindle spin problem.
 

[michellybells]

Wow, thank you so much! I went home and checked, and sure enough that via was indeed corroded and not making contact with the other side. I scratched a bit of the solder mask off on the top and bottom and soldered in a small bit of wire. Suddenly I had 5v going through and the problem was solved! Thanks once again.

[Necromancer]

It's always nice seeing a system fixed up for many more years of gaming fun.  Good job, guys.