Disc Drive Repair

Various factors can come into play which may make a disc drive not function correctly. If all else fails, you will likely need to replace the disc drive or opt for an Optical Drive Emulator (ODE).

"Disc doesn't spin at all"
For most consoles, a small lever or leaf switch is physically depressed when the lid is closed. When the lid is closed, the console should spin the CD and start to seek. Generally, if the lid is closed  and the console doesn't spin at all it can be assumed that either the leaf blade switch is broken or the motor is dead. Below is an example of a leaf blade switch on an FM Towns Marty.

Generally, the fix is to either replace the broken switch or remove it and permanently wire the lid switch together so that the console always thinks the drive is closed.

"Disc spins but laser doesn't move"
If your console has a laser on rails that moves into position under the disc, ensure that it is going the full range and ending in a correct position under the disc. If it's not, you can attempt to clean and re-grease the rails with dielectric silicone grease.

"Reads original discs, but not burned discs"
Often times when a laser is going bad, it will lose the ability to read burned discs (such as audio CDs) as original pressed discs are more reflective and easier to read. A pot tweak should bring back its strength. In order to access the Marty laser, totally disassembly and desoldering of the motor from the disc drive PCB is required.

"Spins but doesn't load original discs"
Wipe the laser lens with isopropyl alcohol and a cotton swab. If it still persists, you can attempt adjusting the laser if you have patience.

Trace Rot
Trace rot or otherwise damaged traces are a possibility. Here are two photos of an example where trace repair would be required.

Bad Capacitors
Leaked, bulging, or just plain dead electrolytic capacitors can cause various issues including the disc drive not working. Look closely for the top bulging or the top/bottom leaking and clean and replace them if they are. Failed capacitors can show no apparent signs of failing, so it may be worth replacing them to eliminate another factor in troubleshooting. Generally, the only capacitors that would leak or bulge on a Marty disc drive PCB are the bipolar ones that require radical disassembly to access.

Dead Laser
The kiss of death. You will likely need an ODE from Deunan to revive Marty. Alternatively, there are unconfirmed reports of certain Panasonic CD players with a compatible laser for Marty.