Sony DRU-500a - where does this part go?

[Mr. Blue Sky]

A month or so ago, my Sony DRU-500a burner started acting odd. When I hit the eject button, it would try to open and then close again never actually opening.

I pulled the unit out and popped the cover. When I did, a small white plastic washer about the size of a quarter fell out. I cannot figure out where it goes!

I reassembled and reinstalled the unit without the washer and it works fine except it's rather loud and it vibrates when a disc is playing. This does not effect the playing of discs. I'm trying to avoid using it until I can figure out the part goes. Is a schematic available online?

Any ideas?

[Lynchchrist]

The first thing I thought when I read your question was that the washer was actually one of those spacers that comes in a spindle of blank discs. Maybe somehow it adhered slightly to the disc during manufacturing or anytime after that and you inserted both inadvertantly. (thus unbalancing the turntable thingy! Nice tech term for you!) I have this same drive so I hope you get to the bottom of this mystery without a big bill. Best of luck.
Lynchchrist (an avid ELO fan by the way Mr. Sky) (zoom DVD is incredible)