Strange audio problem w/ Duo, not caps

[eugenek]

Hey all, hoping someone can help me with a strange problem that I can't really find an instance of anywhere else.

I just bought a Turbo Duo off eBay, and aside from reeking of smoke and being absolutely filthy, it mostly works. I've been having a strange problem with redbook audio, but I don't think it's a capacitor issue.

Basically, the redbook audio works fine and then it's like the laser loses its place or something. Like, I'll be playing Ys Book and the overworld music is playing and the drive will suddenly whir and the music buzzes and cut out. BUT, if something happens that makes the redbook track reload, like if I enter a town and come back out, the music starts up just fine, which is why I feel like it can't be bad caps.

When I play audio discs, everything's fine for a while and then it goes berserk skipping around tracks...it'll play track 1 for a couple of minutes and then in the span of 2 seconds, skip to track 5 and track 11 and track 12, that sort of thing.

Does anyone know what the problem might be? Has this happened to anyone before? Thanks for any help you guys can provide.

[Necromancer]

Assuming that the discs are clean and undamaged, it sounds like a lens issue to me.  I'd start with a thorough lens cleaning and a good lube job on the gears and other moving bits, then play with the pots if it's still having troubles.  If this doesn't get everything back to nine by nine, then you're probably going to need a new laser.  Best of luck.

[eugenek]

Yeah, discs are fine...I'm glad it doesn't sound like caps, I can't a solder a thing but I might be able to replace the laser assembly.

Is there a chart somewhere with the pot locations? Would I have to adjust the pots on a new laser assembly right out of the box too? My preference is to not bother with pots because of the nature of the problem. I can't imagine how long it would take to fix if I had to make a tiny adjustment and then wait 10 minutes every time for the problem to rear its head so I could take it all apart and do it again.

[papa_november]

The test points on the laser pot are easy to reach with multimeter probes. If you want, you can adjust your new laser to have the same setting as your old laser when you put it in, and then go from there if you're having problems.

Do you have any non-burned games? Do they do this too? It's important to have at least one non-burned game (no matter how terrible) for testing.

[eugenek]

Oh, forgot to say, this isn't a CD-R issue. These are all authentic pressed games-no burned discs.