Record DML320 fault

[icewoodturning]

I have a DML 320 that I use to carry about for demos. It has now developed an intermittent fault whereby the speed will suddenly drop to the bottom of the speed range. Sometimes the speed comes back up after a short time, other times i have to switch it off, leave it for a while and switch it back on again. No fault codes appear on the display.
Anyone experienced a similar problem / have a solution?
Does anyone have a circuit diagram for the controller?

[burywoodturners]

We use this model as the club lathe and I downloaded the full instruction manual from record Power website.
Good lathe

[Paul Hannaby]

Similar faults have been noted on a number of different lathes and they are mostly due to dust getting in to the potentiometer which controls the speed. You might be able to blow it out with an airline but if the fault is due to wear, the best course of action would be to replace the potentiometer.

[Tim Pettigrew]

Similar faults have been noted on a number of different lathes and they are mostly due to dust getting in to the potentiometer which controls the speed. You might be able to blow it out with an airline but if the fault is due to wear, the best course of action would be to replace the potentiometer.

I had exactly the same problem with my Record DML305 VS controller. Caused as Paul suggested by wood dust ingress.  Dismantling and cleaning solved the problem. An application of sealer round potential ingress points helps prevent a recurrence.

[icewoodturning]

Having stripped it down, there was a surprising lack of dust inside the control unit, and the miniature potentiometer was fully sealed. The fault turned out to be a bad solder joint on one of the potentiometer terminals. Just the heat shrink tubing holding it in place. Re-soldered and seems to be ok now.

[Wood spinner]

Well done finding and repairing the fault