In message , The Natural Philosopher
writes

So there is no real concept of 'voltage rating' - it tends to be an
arbitrary number stamped on the motor by the manufacturer, but in
reality it means almost nothing.

Thank you! Bottom line, apply my 5v as before, and gradually increase
the voltage. My ears will tell me when I need to back off.

Actually, high speed is not important. Just the opposite, in fact.
Vague plan is to use this record turntable as a toy train loco
turntable, so slow speed is good. How quickly the TT will stop rotating
once power is cut, I don't know yet, Assuming not terribly quickly,
either some form of indexing will be required, or a lot of practice!

Next step is to try and find a replacement drive belt, which may not be
easy.
--
Graeme