When I
restored a broken Duo a few weeks back, upon testing I realized the cdrom unit was making a terrible noise when reading discs. The center hub appears to sit ever so slightly too low in the casing. My initial quick fix was to put a few small pieces of electrical tape to raise the disc height.
While this worked, its not aesthetically pleasing. After some trial and error, I finally found a thin enough o ring / rubber gasket that eliminates the need for tape. The spare o rings that come with vape tanks seem to do the trick perfectly.
(In my case, one from a Nautilus 2 kit.)
