Beogram 4004 slowing down

[Gunnar]

I’ve had no problems with this player since I cleaned up some funky old grease and everything was working great. Now it will randomly slow down. I replaced the belt and it was fine for about half a record then slowed down again.
Would love some ideas on this

Thank you!

[spassmaker]

Hi Gunnar

My question is if the slowing down is sometimes for a second or slowing down for longer time.

first case from my experience there is a problem with the spark snubber diodes (TVS diodes) in the motor. Find out detailed information here:

https://beolover.blogspot.com/2021/12/Beogram-4002-dc-motor-spark-snubber-replacement.html

second case  from my experience are the dryed out motor bearings. Detailed information here:

https://beolover.blogspot.com/2023/11/beogram-4002-dc-platter-motor-restoration.html

and here:

https://beolover.blogspot.com/2021/10/beoparts-dc-motor-bearings-tested.html

 

Kind regards

Christian

[Gunnar]

It slows down for a continuous time. Usually I have to turn it off and leave it off for it to even change back to normal. I will check out the links and see if I can get it figured out

thank you!

[Dillen]

You don’t state if your deck is a DC- or AC-motor version, but in general:
Dry motor bearings (if never replaced it’s time now).
Bad speed relay (if never replaced it’s time now).
Bad speed trimmers (if never replaced it’s time now).
Bad contact in speed fingerwheel-trimmers (clean them anyways).
Cracked solder joints at PCB connectors (later decks only), particularly the one for the speed dial panel.
Bad TVS diodes in motor (not that common but it does happen. AC-motors don’t have them).
Any combination of the above.

Martin

[Author]

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