Beogram 4000: Platter Motor Stopped Working

Last year I restored a Beogram 4000 from a customer in the UK. Unfortunately, he recently contact me since the platter motor stopped working. 

After receiving the unit I put it on the bench and started looking into the issue. first I checked the power rails and the reed relays. Everything tested fine. The next step was verifying the motor signal. I measured at the motor capacitor, and there indeed was no signal.

So I did the classic 'follow the signal' approach. I measured the oscillator signal at the collector of TR8, which checked out o.k.: 

The oscillation is not a perfect sine wave, since I had to replace the light bulb in the Wien oscillator with diodes when I restored it last year.  But so far so good...now I measured at the base of TR9, which should essentially show the same signal, just shifted to zero V since it is coupled via C6 to loose the DC component. But the signal was gone:

So it had to vanish somewhere between TR8 and TR9. I measured all the connections between TR8 and TR9, and it turned out that the signal vanished after the motor trimmer VR3. I replaced VR3 with a modern 5k 25 turn trimmer, but no cigar! The signal was still gone after the trimmer. At that point it dawned on me that there must be a short to GND somewhere. A closer inspection of the board yielded this:

R24 and R20 were touching! Something had bent the two resistors together, which effectively connected the base of TR9 to GND. I bent the resistors apart, and voila: The motor signal returned. This is the 33 RPM trace

and here is the 45 RPM.

So the trimmer had been replaced unnecessarily. This shows the new unit peeking through the access hole in the PCB for adjusting the motor voltage:

I put the platter on and a cartridge to see if I could play a record successfully. But the arm did not lower on the record. I realized that the sensor arm was dark, i.e. no power to the LED light source I had installed last year. I measured the voltage at the LED and it turned out that it was 0V. So I looked for interruptions in the connections between the PCB and the LED. And quickly I found the culprit: The yellow wire that connects 6V to the carriage had broken off its terminal on the PCB:

I soldered it back on, and now the deck is playing beautifully again! I will play a few more records, and then it should be time to travel back to the UK.