Interesting speed problem with LAB 440

[caseyholford]

Hello everyone,

I’m posting after having sifted through previous posts and not finding one that fits my specific case. I acquired a Realistic LAB 440 TT earlier this year which was supposed to be functioning perfectly. I found upon setting it up that I right away got this odd speed problem - on 45 RPM it invariably locked and had no problem, but on 33 RPM it would sometimes unpredictably slip out and speed up. After consulting a friend more experienced with old hifi equipment, I used deoxit to clean the speed switch internally, and the pitch adjustment. I also did a complete recap of the motor board and the power board. The problem went away for a while but would recur intermittently. It’s since come back with a vengeance. I used D5/F5 on the internal 33 RPM calibration pot most recently. I’m about to try some oil on the motor. If anyone else has any thoughts about what might be causing problems on one speed setting but not the other, I’d be glad to hear them. Thanks and I hope everyone had a nice holiday.

 

[caseyholford]

Update - jostling the TT up and down a few times seems to have enabled it to hit 33 RPM. If that suggests anything to anyone I’d be grateful to hear. Perhaps it needs a replacement motor?

 

[Montycat]

It might be a bearing or bushing or thrust plate issue with the motor. Jostling it suggests that and less of a problem on 45 might be because of greater momentum at that speed?