Squeaky Turntable in TEAC LP-R500

[Old Sparky]

The record deck, which appears to be a BSR P265 or clone thereof, in one of the above, has developed an annoying squeak about once per revolution at 33RPM. If it is run for a few seconds at 45 or 78RPM, the squeak temorarily disappears when back on 33. I haven't taken off the turntable, but it's almost certainly belt driven.
What could cause the squeak - could it be a lubrication problem. The playing speed is correct and constant, so I'd rule out belt slippage.

[tiv48]

it's not a BSR turntable that I recognise . more likely the cheap (nasty) type used in those USB record players,
I had a steepletone for repair that had the same fault there was a crack in the plastic by the bearing(sic) and it was the edge of the platter scraping the base .some aradite and a spacer washer fixed it .
I cant believe teac make something like that.
Rob T