[edgoffin]

Figured I'd ask the question here.

Just this past weekend my turntable started acting up.

Yeah, agree with above -- both of those make it sound like a motor issue. Disconnect from the speakers and see if you still hear the hum -- that would point to the motor as the source. You saying it seems to start after a few seconds makes me think it's motor related. The cartridge could then also be picking up the hum and amplifying it.

The hum could be grounding or interference from other electronics, that's the simplest source for that type of sound. My ground on my cables occasionally comes loose and I get a low rumbling hum. Assuming it's grounded, if there are other electronics nearby unplug them and see if the hum persists. Sometimes they can cause interference and it's picked up by the cartridge.