Powermatic 3520A speed problem

Re: Powermatic 3520A speed problem

techsan from Japan

I have a same experience with my friend’s Vicmarc VL300. In his case the input circuit of the inverter was broken. So the potentiometer didn’t work at all. Please make sure whether the inverter is broken or not. At first you switch off your 3520A and pull out of the power supply cord and wait 5min. to reset the microcomputer of the inverter. And then you can switch on again and make sure whether the problem remains or not.

Re: Powermatic 3520A speed problem

Philip Duffy

Jim, I have the original 3520 and will caution you that the speed control on my machine moves at the slightest touch- -many times by the mistake of a hand brushing against it while doing something else. I tried to slow it down by wrapping a rubber band around the shaft. That has helped some but I am always aware of this problem and proceed very cautiously when touching anything in that vicinity. One good option is to turn the speed to zero every time you shut off the lathe. Merry Christmas! Philip

Re: Powermatic 3520A speed problem

Bill Howatt

I would suspect a broken wire feeding the speed potentiometer but since it is all one unit that is unlikely but you never know. Could be a bad control but it could be a bad anything since it is all part of a complicated circuit.

Try running the control minimum to maximum several times to see if it cleans some dirt out. You could try compressed air and open the unit up to see if it is covered in dust all over the electronics.

Bill