I have bad experience with old CD players, specifically a Quad CD77 with a CDM 12.4 laser mechanism and a TEAC VRDS 9.
One problem is that in many cases, plastics used on the laser lens housing get polymerized with time.
If the lens itself is made of plastic, the laser fails reading the CD properly. If the lens mount gets polymerized, the laser gets misaligned with obvious results.
The thing is that even if you get hold of an identical spare part, there is always a risk that its plastics got polymerized just by sitting on a warehouse rack.
Apart from that, components age with time, especially drawer motors and caps.
I would avoid any old CD player, unless I could get it dirt cheap.
One problem is that in many cases, plastics used on the laser lens housing get polymerized with time.
If the lens itself is made of plastic, the laser fails reading the CD properly. If the lens mount gets polymerized, the laser gets misaligned with obvious results.
The thing is that even if you get hold of an identical spare part, there is always a risk that its plastics got polymerized just by sitting on a warehouse rack.
Apart from that, components age with time, especially drawer motors and caps.
I would avoid any old CD player, unless I could get it dirt cheap.