CD-ROM² are so fickle.

[Ergot_Cholera]

I got an IFU with CD-ROM² and (obviously!) the CD-ROM² failed to work, no movement or anything. I opened it up and replaced the caps and the middle gear (the original seems okay to be honest) and then I removed the old grease from the spiral sled thing and applied new lithium grease and....  now it is working perfectly! 
I have another CD-ROM² which worked perfectly until.... I thought I would clean and regrease the spiral thing, I put it back together and now it doesn't work.

[Keith Courage]

Double check that you put the lens ribbon cables back in directly. Very common for lots of people to accidentally put the larger ribbon Cable in backwards. The contacts should be facing outwards away from the center of the drive. Also, make sure that the grounding strip that goes on the same lens ribbon isn't accidentally touching the motherboard and shorting things out.

[Ergot_Cholera]

I always put the ribbon cables back correctly, that is why I am confused as to why it should suddenly stop working. Everything is the same apart from the cleaned and regreased spiral rail.

[thesteve]

if it has a 225 laser in it the wide ribbon needs to be centered in the connector

[Ergot_Cholera]

It has a 220a laser. I might just have another go at positiong the ribbons though, I can't see what else the issue may be.

[Ergot_Cholera]

Found the issue, it was hard to see. The larger ribbon cable has a cut in it across the first four traces caused by pulling against the metal clip.
That metal clip is an accident waiting to happen, it acts like a razor blade on the cable if there is any tension put on it.
I have another broken kss-220a with an intact cable, so I swapped it over and now it works about half the time I try to play a game. The pots on the cable were positioned slightly differently, so I moved the replacement into the position of the original (was this a bad idea).
I don't want to mess with any of the pots on the board.

[ScoreAddict]

I'm havin issues with my CD-ROM² too! At first I thought the laser was a goner but when I swapped it with the laser from a Sony Discman it worked just fine in there! Whereas the laser from the Discman has the same problem in the CD-ROM² that the original one had. So it's clearly not the laser but most likely the pots?!? And what about the caps? Are they as bad as the ones from the Turbo Duo?

[thesteve]

ok on the ribbon swap moving the pot to match the original was correct
you will need to adjust the pots on the board

[Ergot_Cholera]

There isn't a guide for adjusting the pots of the CD-ROM² (that I could find). Are the pots numbered for functionality in the same way as a DUO, or did they decide to switch them around (just to be awkward)?