It is almost certainly the belt either worn loose or stuck in the "default" shape that it's been sitting in for so long and not wanting to rotate.
Some people report boiling the belt in water helps tighten it up. I usually just take them off, roll them between my fingers a bit and put it back on inside out from the way it was originally installed.

jmarsh wrote on 2024-05-17, 15:28:

It is almost certainly the belt either worn loose or stuck in the "default" shape that it's been sitting in for so long and not wanting to rotate.
Some people report boiling the belt in water helps tighten it up. I usually just take them off, roll them between my fingers a bit and put it back on inside out from the way it was originally installed.

And why does it work just fine when a CD is inside?

And why does it work just fine when a CD is inside?

Because the upper part of the mechanism that holds the CD in place is magnetic. With a CD inside, the magnetic force on the lower part is less than when both parts make direct contact without a CD between them.
Had the same problem with my DVD player. The belt was out of shape, thus the tray would only open when there's a DVD inside or if I gave it a slap on the top (which helped overcome the magnetic force). After having replaced it with a new belt it's been working flawlessly again.

I am nearly certain that it must affect all Plextor drives out there, so you will likely have seen it too, if you have a Plex.

I do have a Plexwriter 12/10/32A, but I believe it doesn't use a rubber belt for the tray mechanism (have to check it once I'm back home). It is still opening fine without a CD in it.

OK, makes sense.

Moved the belt a bit out of "phase", so the assumed sharp bend is now elsewhere. Seems to work for now.

Thanks!

My oldest is the one before the "premium", the 48/24/48A, and I have observed it with basically all the drives since.

In addition to some Plextors, I have also seen this with an LG DVD-ROM. I t was less than 5 years old at the time.