Welcome to HTF, Steve!
I had a CLD 3090 back in the day. I don't know what could be the problem, but considering the age, I suspect your 3080 is just worn out.
Cheaper to buy another one. This one even comes with Cousin Vinny...
http://www.ebay.com/itm/CLD-3080-pioneer-CD-CDV-LD-laserdisc-player-remote-very-rare-/221165175278?pt=Vintage_Electronics_R2&hash=item337e78c1ee
By the way. I still watch LD and CED(RCA VideoDisc). I have a spare of both...Not selling my extra LD though...
could be the laser, could be the spindle motor, could be both. it's likely one or both of those being just plain worn out, i think.
indeed, getting a functional replacement would be the most inexpensive route.
also lube the gear and shaft works with WHITE LITHIUM GREASE and LIGHT MACHINE OIL,
both of which can be obtained at your local HOME DEPOT.
a little preventive maintenance goes a long way, and, as a result, my own 1987/1989 PIONEER CLD-3030
purrs like a kitten to this very day...