Those were nice presents! Is she available? ;-)
Sounds like you have the AC motor version. From what I understand, this could be a failure of the phasing capacitor (150uF bipolar, one of the four) or the motor itself. You should also check the voltage at the other end of the 4000 uF cap feeding the motor (another one in the bank of four) - it should show 11,4V in average. If not, one of the transistors driving the motor may have failed - I think TIP31 and 32, in TO220 case mounted somewhere off the circuit boards.
I presume one of the experts will correct me sooner or later, I just jumped in because we have a lot of traffic now when the forum is back online. Welcome, and I'm sure we'll have your Beogram sorted sooner or later!