Drum sander conveyor speed controller wonky...

[Bill Kugler]

Background: I have an elderly Toolex 25" dual drum sander (Toolex no longer sells tools here in Canada), it is the virtually the same machine as the King Industrial dual drum sander, the Woodtek MS-25, and the General International 15-250M1. I bought it used, and spent 10 hours on a nice day last summer, doing the maintenance work that the previous owner did not. It now works fantastic, other than....

Problem: The speed controller for the conveyor motor is very wonky/finicky. It works fine, but in a very limited band... the indicator goes from 0-10, and from 0-6 is full stop, 6-8-ish runs from stop all the way up to full speed, and 8-10 is full speed.

Any electrically inclined people know what's going on here? Or if there's a way to fix it without replacing the control board? The machine works great otherwise, I'd just like to have a little finer control of the speed for slower passes...

Also, does anyone else have one of these? Is the control board actually interchangeable with the other machines I listed? If it comes down to it, I may break down and order a replacement.

Thanks!

Will

[Ben Grefe]

Bill,

Without actually looking at the controller, I’d have to wager that the controller is a potentiometer. Basically a variable resistor of some sorts. You theoretically should be able to take the box apart, look at what’s in there any buy something with identical specs (resistance range, DC/AC volt capability).

Another approach is to look for one of the other companies and see if they still sell that part. Just looking for the Woodtek model I see it’s listed as a replacement part (https://woodworker.com/pdf/109-352manual.pdf). Probably a lot easier to just buy that one as you know it’ll work.

[Bill Dufour]

I doubt a potentiometer. I assume it is a universal motor with brushes? If so I assume it is a scr speed control. You can buy these in a box as a router speed control or a naked board from the bay. You could mount the naked board into your box or into any box and bring the three wires out to a potentiometer.
Bill D.

a 4000 watt one is about $4.00 delivered from china.

[Jim Becker]

You might also try cleaning the speed control internally...there could be a build-up...before moving to replacing parts. Take it apart and see what's going on inside. (unplugged of course. :) )

[Richard Coers]

I doubt a potentiometer. I assume it is a universal motor with brushes? If so I assume it is a scr speed control. You can buy these in a box as a router speed control or a naked board from the bay. You could mount the naked board into your box or into any box and bring the three wires out to a potentiometer.
Bill D.

a 4000 watt one is about $4.00 delivered from china.

Performax used a DC motor on the belt. The OP will have to tell us what the motor plate says for any kind of good info.

[Bill Dufour]

Probably dust or wear on the potentiometer. You really have to disconnect it from the circuit to test. I would cut the leads and then solder wires for a remote mounted unit.
Bill D