Thread: MOF001 Speed Controller Problem

When you say "behind the rheostat" where do you actually mean? I have one of these and it happened exactly the same way - very little use. I have relegated it to a cupboard not wanting the pay for a speed controller and then have it fail again.
Thanks,
Dallas

OK, here is the photo. The cardboard is just a strip of thin cardboard (manila folder actually) folded over a few times and wedged in there. Hopefully the same trick will work for others (and hopefully it will last - it's been 24 hours so far and still going)
router.jpg

That's a nice simple fix if it works. I will give it a go when I get out in the shed in the next day or so.
Will let you know how it goes.

I had a go at this fix tonight but it had no effect. When running at reduced speed it sounds like it is getting power on and off like you are flicking a switch, so I think that it is probably in the circuit board.

Bummer

If you know someone that knows their way around a PCB and are handy with a soldering iron get them to have a look at the PCB. It could be something as simple as a dry joint or another alternative is get a can of switch/contact cleaner and give the pot a good blast. You'd be surprised what doing this can clear up, especially in a dusty environment

It's worth having a play - push it down as well. Problem is that this PCB has solid plastic on the bottom, and epoxy filler on most of the top. That one piece is the only one that isn't drowned in black epoxy.

I gave the rheo a good blow out when I had the top off and also gave it a good poke and prod but it didn't seem to have any effect. I will try some contact cleaner over the weekend and have a bit more of a play as I have nothing to loose.
I find it hard to believe that dust could be the culprit as it had hardly been used when the problem first surfaced.

It may be worthwhile getting someone with knowledge of things electronic to check out the circuit board. It sounds like a "dry joint" where the rheostat mounts to the board. This can be solved by re-soldering the 3 joints. Some of the older lead-free solders were brittle and re-working the joint can sometimes work wonders. Good luck.

I guess if all else fails it doesn't look as if a new controller would be all thaty expensive compared to a new router, and a new component may be a better design and certainly should come with a warranty.

It depends on the complexity of the circuit. Some are dead simple (light dimmers, for example) but others are more complicated. As the machine has had little work I would look first at "dry joints" on the speed control potentiometer, then look for problems in the potentiometer (the carbon resistive track can fail or get dirty. If the assembly of the board was not quite as professional as it should have been (lowest price always wins the job) then you can have problems down the track.
Warranty? You had the thing open, they can claim your warranty is void, especially if they smell cleaner. But good luck if you go down that road. If there has been a number of failures it points towards a design fault and they may play nicely with you. Good luck.

Unfortunately the machine is quite a few years old now and has been sitting at the back of a cupboard. It was Peter's possible fix that made me get it out and have another go. I have got some contact cleaner and will have another play with it over the weekend.

I had one of those old Triton routers, they were a good machine and worth fixing. Mine was lost in a bushfire back in February but I would do some investigating about repairing it if I were you. If the machine was used only on a router table you could probably ditch the built-in speed controller and wire in a remote speed controller in a box on the router table. I have the feeling one of the electronics magazines did some designs for something that would do the job, probably there is a kit of parts available from Jaycar Electronics that would do the job. I built a "soft start" gadget for my Ryobi table saw from a kit from Jaycar. Might upgrade to a Makita saw this time around, it's got soft-start as standard.

The problem with repairing these circuit boards is that they are buried under a centimeter or so of hard black epoxy. I am sure that help protect against dust and vibration (as well as anybody who wants to copy it). It does make repair of the board almost impossib le though. That one pot is the only component not drowned in epoxy, and that is hard to get to due to the casing of it. I think it is really supposed to be a throw away item if it malfunctions (the speed controller I mean, not the whole tool).