# Bosch router speed control flaws



## badtheba (Jul 3, 2011)

So I worked for a cabinet shop for several years, and the owner had 3-4 Bosch routers from various years. Any that had variable speed eventually had problems with the speed control. We never bothered to take one apart, as they generally worked and the speed drops or variations were temporary; they would return to normal when bumped or tilted. So we always assumed it was just a potentiometer with sawdust in it or something. There were Milwalkees and others around to use in a pinch, but I always thought the Bosch motors were smoothest.

Fast forward to now, and I just purchased a Bosch plunge router at a garage sale. Knowing about the possible issue, I asked to plug it in and run it. Sure enough there are speed control issues. However, this particular one goes at full speed all the time, instead of dropping randomly like the others I have seen. So the seller dropped the price from $80 to $50 to cover most of the replacement part.

I get the thing home and take it apart thinking I'm pretty handy with a multimeter and a soldering iron. Well the bastard is epoxied in there, or at least some kind of resin glue harder than hot glue. It looks near impossible to cut out of there without damaging the circuit board. The part online isn't too bad, in the $33-45 range. But still, I figured if I fixed mine I'd go over to my old boss's shop and fix his after mine. If all full size Bosch routers are like this then it's pretty much a non-repairable part.

Has anyone else run into this same thing, or found failures with speed controls on Bosch routers to go bad more than other brands? Having come from a background working on fitness equipment, and now primarily doing computer repair, I'd love to save the money and just tear it apart but I'm assuming I'll destroy it. Unless I can melt it out at the perfect temperature. I'll post a pic next post. I'm sort of disgusted.

It's this part: http://www.ereplacementparts.com/control-unit-p-49947.html


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## badtheba (Jul 3, 2011)

Pic of backside of speed control.









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## Canarywood1 (May 5, 2012)

Bosch is just ahead of the iPhone companies, as i understand you can't replace the batteries anymore.


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## hkstroud (Mar 17, 2011)

I guess I'm confused. The replacement part looks like it is not only the switch (the actual electrical switch) but the cover and the knob. In other words the complete assembly. Looks like you would just remove the wires from the old and connect them to the new, snap or slide the cover in place. Also looks like the actual switch is riveted to the cover.
I must be missing something.

PS
I would blow that switch out with compressed air before replacing. Just in case.


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## badtheba (Jul 3, 2011)

hkstroud said:


> I guess I'm confused. The replacement part looks like it is not only the switch (the actual electrical switch) but the cover and the knob. In other words the complete assembly. Looks like you would just remove the wires from the old and connect them to the new, snap or slide the cover in place. Also looks like the actual switch is riveted to the cover.
> I must be missing something.
> 
> PS
> I would blow that switch out with compressed air before replacing. Just in case.


We have tried blowing all of them out. The assembly is so tight and sealed up that it does no good. Obviously it's not too tight to allow something (sawdust, moisture) to get in though, or it would work forever.

You're right, the replacement part is the entire assembly. It cannot be disassembled, which is why I was asking if anyone else dealt with this on a Bosch. As I got money off my purchase price, $30-40 isn't really that bad. But for my old boss's similar routers that's $30-40 times 3 if he wanted to repair all of them. Seems a little bit overkill for what's likely just dirty contacts.


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