old Sears turntable not spinning

[Bridget]

I have a vintage Sears 8 track/turntable/radio combo unit (from the 70's, I think) that will no longer spin vinyl. I've tried taking the platter off to see if it's a broken belt but the darned thing won't budge! Anybody have any ideas? I've looked all over the internet w/o much luck.
Thanks!