Thanks for the reply.
Yes, we know that the Duo's audio problem is not caused by the cd-rom mount but by certain electronic components on the main board (and the problem does not occur with Duo-Rs and RXs.)
However, the laser diode of the Duo/R/RX becomes weak sooner or later (rather sooner, now that the drives are all 15+ years old). I already had one Duo-R whose laser died; had I had a replacement CD pickup back then I could have saved the console, as it was in perfect order otherwise.
So, the question remains, will the Hitachi CD-Rom mounts work?
Do you have any idea exactly what type the Sanyo CD pickups that guy from HongKong is offering are? Are they better suited?