Swapping the optical-drive assembly over is pretty easy on these little fellas, but this replacement came with some extra issues.

Sony used several KSM-440 variants across the PlayStation family. The PS one uses the KSM-440BAM, while earlier consoles use other assemblies. They aren’t universal drop-in replacements, so check the flex cable and mechanical fit for the particular console, even the chubby ones.

I suspected some of the replacement assemblies I’d bought were aftermarket parts. Just make sure your laser isn’t corroded like some of mine were…! ;)

Sources