PC Engine CD drive requires warm up

[soop]

I have a question.  I have the warm-up issue, but when I move the gears with my finger, there's no more resistance than I would expect from the motor.  Then when I remove the motor gear, the middle gear certainly isn't stuck.

The more I think about it, it seems like the problem might not be gear related.

Just to describe it again, my issue is that the CD player lights up, makes a noise, and shunts the CD slightly, then immediately powers off.

Might this actually be a capacitor issue?  I could look for corrosion, but I don't think it's a great idea for me to replace them if I'm not sure that's the problem.

[Keith Courage]

If it spins slightly and stops right away it is generally the CD lens going bad. It would not spin at all if it were the gears.

[soop]

Yeeesh.  Ok, I replaced the laser, and now it powers on longer, but it does different stuff:

It makes a high pitch whine and switches off
It does the same as before, powers on briefly and shunts the disc
When you press run, it says "PC" in the display, and either sits there doing nothing for ages, or whines.
It also makes a sound like the motor is going, but I don't think it is.

I have no idea.  Pretty sure I assembled it right, apart from a missing screw on the top cover plate (inside under the CD).

Any ideas?

*Edit* 3 things worry me;
The blush on the lens may have been rubbed
The ribbon on the unit was sealed in, and may have been damaged during extraction
The plastic link to the worm mechanism may not be fully attached - Only three screws of 5.  But it does move the laser when turned.

Re-edited for clarity (I posted it from my phone last night).  Should I create a seperate topic, or is it ok in here?