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Hi there, loving the info on these forums!

I recently acquired a PC Engine Duo (not R or RX) with 'non-working' cd-rom for a good price and am trying to get it running.

Here's what I know:
-PC Engine Hucards work perfectly.
-All sounds (adpcm drums etc.) appear to work even from headphone port.
-Motor spins, it started off not playing cd games but occasionally played the first track of a music cd with stutter.
-There's no obvious sign of cap leakage, bursting, or fluid on the main board. I might have lucked out with that, but I won't rule it out.
-I'm using a music cd to test its capabilities. Seems pretty obvious to literally 'hear' when there's a problem. Games are not fully booting yet.
-I've removed the plastic housing cover over the cd assembly for kicks, no discernable changes.

Now here's where I came in. I followed the calibration guide (very nice) and did some adjustment on the pots. Now it reads the first couple tracks of a music cd flawlessly, no stutter. Progress! But it has trouble reading past say, track 6-7 on a 20 track cd. I heard that this might be V105's tweaking (spindle speed correction?), but I wasn't able to get a huge range of adjustment on it - basically I could get + or - one track to read. Depending on its position, I could read track 7 if I booted it up cold to that track but if I was skipping around, no dice. Which made me question if it could have something to do with the motor/rail mechanism - it looks like it slides in to seek, gets lost and gives a click or two, re-orients itself at the outer edge, and then back in the track position, ad nauseum.

Alright gurus, what can I try? I'm not going to rule out replacement parts (as much as I'd like to) but there's good signs of life even as is. Tips?

If your caps are still original, they may be the culprit.  They affect sound most noticably but I've had several units have reading issues that were corrected by a cap change (all of them)

Alright, sounds fair enough. I'm more than capable to do it, just a matter of time crunch lately.

Which ones are related to laser/cd assembly operation? I assume just the ones south of the cd assembly? I know from reading around that the common response is to 'replace all of them' but as far as I can tell the sound output is working great, nice and loud too. I'd rather not add another variable to this if I don't have to.

I dont think we've tracked down all the specific ones directly related to the laser but i know the 3.3uf 50v is part of it.  Even if your sound is fine.. its still important to do them all preventatively. I have yet to see an original duo without a single cap leaking.  You probably wont see the leaked ones until you remove them.

it could be focus related, as the later tracks require better focus control.

ASIDE: Welcome to the forums. :)

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