It's been a couple of years, so my memory is vague, but the only parts I can remember tampering with were plastic - no wires, no solder, no oil, no motor, and no circuits. There was a plastic piece which was.. "off-track", and if I recall correctly, this piece was near the middle of the front, rather than the sides. It was a similar situation with my Yamaha CRW-F1, except that same plastic piece was broken rather than off-track, like it had a very obvious weakpoint where a break was simply waiting to happen, while this didn't seem to me to be true about the plastic piece serving the same function inside the Premium.
I'd like to help you further, but I'm not quite charitable enough to take apart one of my Premiums again, and retrace my steps.
But I am fairly confident that it's a non-electronic fix.
My Premium-U had to be stepped on before it got into its non-ejecting status, and the fact that it was still repairable without additional resources, really says a lot about the drive. The Premium-U is basically an internal IDE Premium inside a fairly tough external enclosure, and with a different bezel than the standard internal black units. Technically, stepping on the Premium-U shouldn't have made any impact, but somehow it did, and I think if the forces of that could get the drive-tray mechanism(s) off-track, then presumably a rough shipping process could affect the drive too.