Probably a broken plastic gear drive - common fault.
I had one of these units for a number of years which uses a cheap Sony drive unlike more expensive models further up the chain (check out the plastic cover -over the cheap ,cheap motor - which performs no function other to give the impression of some kind of 'audio engineering' )- the VRDS 10 and VRDS 25 are miles ahead in terms of internal build and sound quality. I had both of these far superior models for a number of years as well. Unfortunately, Sony laser KS151A which was fitted to the 25 is virtually unobtainable - any you see will be NOS and sell for around 250 pounds+ sterling 'cos the sellers know they are so rare - Sony stopped manufacture years ago.
I replaced the VRDS 25 with a NOS Sony SACD XA3000ES - the Sony rubbishes the VRDS 25 in terms of detail and presence. Not only that but it operates far more smoothly than the clunky TEAC. Sony beats TEAC not only with both using internal DACS but also through TEAC DT-1 - and I can still get a replacement laser.