Knowledge You Can Build On — Est. 1998
PM3520a Out of Conttrol
Jerry Whitaker
>My PM3520a started going crazy today. The speed changes up and down all by itself. It will slow down then speed up to full rpm without ever touching the speed control knob. If I tap on the controller with my finger tips, the speed will change up or down. Anyone else had this problem or know what to do about it?
Re: PM3520a Out of Conttrol
JL
>Sounds like you have an inverter problem. This can be frustrating and dangerous. Call Powermatic/WMH. If you or someone is handy with electronics, you may "crack the box" and poke around. Maybe if you can get a schematic, you can do this. I have seen one go out on a Delta before. I wouldn't try to turn on it.
Re: PM3520a Out of Conttrol
john Lucas
>I agree with JL. It could be s simple as a loose connection ro very complicated. The inverter is a pretty serious piece of electrical gear. It should be a warranty issue. I hate that this has happened fortunately it is the first time I've heard of this.
Check the speed control knob. I doubt that this is the problem but I would look at all the connections. It could be as simple as a loose or abraded wire.
Re: PM3520a Out of Conttrol
Sean Troy
>I think one of Mike's bugs got into it.
Re: PM3520a Out of Conttrol
Chris K.
>Mike did say that he couldnt find one yesterday :)...
Re: PM3520a Out of Conttrol
Barry Irby
>My Nova DVR 3000 went nuts. It would advance to 3500 on it's own. SCARY if you are turning a twelve inch bowl.
They had me blow out the headstock Based on the idea that there is an electric eye type device in there that watches a set of stripes on the shaft and "reads" the speed. Did not help. The electronics had gone bad and they sent me a new set free of charge.
Yours does not sound like this problem either, because you would think if it went "blind" it would default to either low or high speed. Would be careful poking around until you get the company involved. Don't want to void the warranty or hurt yourself.
Barry Irby
Re: PM3520a Out of Conttrol
Bill Howatt
>Don't have a PM3520A but it sounds like it could be as simple as a bad connection since tapping triggers it. The inverter on my lathe has a terminal strip where connections to the speed pot, fwd/rev switch etc are made. Check those are all in good shape. If nothing obvious like that then you probably have serious internal problems in the electronics.
Bill
Re: PM3520a Out of Conttrol
Jerry Whitaker
>Thanks everyone for your response. I will get on this problem first thing Monday morning.
They would never hurt a 3520
Mike Schwing from Md.
>The inverter on my 3520 acts as an incubator for the bugs. They seem to respond to the faint hum of the inverter as if it were a mother's heartbeat. If I forget to unplug it, when I open the door in the morning they all scatter from being huddles around the electronics box.
No way, weren't my bugs. Those might have been OneWay bugs.
Re: PM3520a Out of Conttrol
David Galloway
>Nick Cook had this happen the other day. Brought in an electrician, turned out to be a loose connection, very simple, hard to find.
