For the BG400X  types with the DC motor, you can install two 470 ohm resistors, one between  P6 pin 4- 5 and one between P6 pin 4-6 , disconnect the original wiring going to pins 5&6 from the front panel speed trimmers. (This will roughly simulate the front panels being set in the middle position as they are 1K ohm devices.) You'll need to re tweak your speed trimmers on the main board slightly to zero the speeds.

You could also probably just jumper pins 4-5-6 together, there will _probably_ be enough adjustment range in the main board trimmers to still allow you to zero the speeds.

If it's the fingeroperated one on the panel, you can clean it.
Give it a shot of contact cleaner and work it back and forth a couple of times.

Martin

Hi both

Many thanks for this, I tried the above, but still have some fluctuations, changed the belt back for the original and this stabilised things much more, but it is still there

I think I have got as far as I can and don't want to risk messing it up - considering now seeing if someone wants to swap it or p/x and a few other bits for another decent non b&o turntable as the condition is excellent, just needs the electronics sorting!

Thanks again, really frustrating and may well come back to it again.

The motor bearings will be next. Clean and relubricate.

Martin

Thanks Martin, you've inspired me to persevere - I shall look at the motor this weekend

Regards

Andrew