Beogram 5005 (alternative version) repair

My parents has the alternative version of a beogram 5005 (that looks like a BG3000) without labels on the back and with orange letters on the front.

When I try to turn it on it clicks once and the 33 lights up in the mini display for 3-4 seconds and then it clicks again and then nothing happens.

When I remove the platter it seems like the motor is trying to move when this happens, but doesnt. The belt seems loose and should be changed in any case.

But what else could cause this behaviour?

Thanks in advance

madskp:

...

When I try to turn it on it clicks once and the 33 lights up in the mini display for 3-4 seconds and then it clicks again and then nothing happens.

....

When I remove the platter it seems like the motor is trying to move when this happens, but doesnt. The belt seems loose and should be changed in any case

 

Please change your belt! Then maybe your problem will be solved.

Can you see that the drive motor turns after you have removed the plate and pressed START?

If the answer is yes, replace the belt!

Otherwise there is a problem with the motor or servo electronics!
The plate must turn to start the beogram (mechanically).

Thanks for the input. After I posted I got an offer to switch it for another working unit, so Im dropping this repair.