Help with my CD drive (again)

[soop]

I've got a couple of white CD-ROM units I mess about with from time to time to try and get them working.  I got frustrated last time and sort of forgot about them.

Anyway, so far I've got this one spinning up, seems really fast, but it's not finding the start of the disc or whatever.  The Track Mode stays on 0, and it spins the disc for about 5 seconds before powering off.

Any clues as to what's happening and which potentiometer might lead to the fixing?

[ApolloBoy]

It might be the caps, have you tried replacing them yet?

[thesteve]

its just not reading yet
how are your pots set

[Keith Courage]

Yeah definitely check the pots to make sure no one turned them way off from the original settings. Also, I find a week or bad lens can cause this issue as well as bad capacitors.

[thesteve]

i agree on the bad laser
its just best to start by looking at your pots

[soop]

i agree on the bad laser
its just best to start by looking at your pots

At the moment, my pots are set very close to the picture in Keith's topic:

/pic06g.jpg

On mine, the 3rd pot on the left is tweaked a hair more clockwise as we're looking at it (won't spin otherwise), and the rightmost one, I've been tweaking all around.  others are pretty much identical.

When it spins up now, it's spinnging quite fast to the point that the revolutions sound into a whirr ratehr than swishswishswish, which I think is how it's supposed to be, and I can hear a sound which I think is the laser being adjusted by the worm thread.

So I think the poroblem is the laser not being able to focus on the start thing.  I believe I've replaced the laser (which stupidly, I didn't test before I took it out of the walkman) but this may be another unit which I didn't.  I have another laser if it comes down to it.

So we're saying right now that if it's not the pots it's likely the laser?

[thesteve]

if thats yours remove the solder blob from the laser ribbon

[soop]

if thats yours remove the solder blob from the laser ribbon

Nah, that's Keith's.  I think I have removed the solder, but out of interest, what effect does that have?  That's a ground, correct?

[Keith Courage]

That was actually a pic I borrowed from the CD lens change topic. Written by BlackandBlue. That is a good place to start to make sure the pots are not all out of place. Try adjusting the pot on the left side of the ribbon cable from looking at the pic and see if you can get the thing to read any discs. If it won't I'd say it is either a bad lens or capacitors. It could also be a bad trace on the board but that is usually a last thing to try if the rest doesn't work. Most likely it's the lens.

[thesteve]

the solder blob shorts something (I havent looked into what)