# Dremel controller board repair



## Norppu (Sep 11, 2020)

My Dremel started snapping about five years ago. First it pounded its time and then went well into the rest of the evening. Then the pounding time increased until last week it knew nothing more than pounding.
It’s such an old model that it would have been perhaps wisest to just let it be and look for some new mini drill. However, I doubt it would last for 12 years ...


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## Bi11Hudson (Sep 12, 2020)

The Dremel is a fairly straight forward direct drive drill. There's not a lot to go wrong. There are the brushes and the bearings (sleeve on mine) that are repairable. Then there is the armature itself. If the armature has a short or open, the simplest solution is just to replace the tool. Dremel has "upgraded" their models, and diversified, to the point that fitting up parts to old tools is a hit or miss proposition.

My Dremel(s) have been around a long time. One of them 30 plus years. Hell, I've been married this time for 30 years. Call it 40-50 years old.  But they don't get used often. The oldest one has had a new set of brushes about 20 years ago. The newest one has a "turn button" for speed control. I've never had an armature fail, but it could easily happen. Listening to your video, it sounds like a dry bearing. Or possibly an armature segment shorted. I do have a "growler", the test fixture for armatures. But I haven't used it in so long, I probably couldn't distinguish an error any more. Repairing a small armature was a pain in the wazoo when I was in good shape. That was then. . .

I would say check the bearings and brushes. If they're OK, then just get a new one. The tool itself is still reasonable if bought alone. The "kits" is where the price goes up, fast. For what it's worth, the one you display is a fairly new model. Parts should still be available. One of mine is so old there are no parts available. Even the aftermarket bushings for solid mounting don't go back that far.

In passing, I had a "drill press" adapter for one of the old ones. Even the older model was too unstable for doing circuit board work. The net result was a Horrible Fright bench top mill as a drill press.

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## Norppu (Sep 12, 2020)

Bi11Hudson said:


> The tool itself is still reasonable if bought alone.


This is my thought too. However, I would prefer a miniature drill that would not be that heavy because I am using very thin drills with it. Being carbide they break if one uses too harsh language near them. I also would like to get one that does not suffer from such a failure which seems to be intentional or/and is poor engineering at the least.
I checked the armature and the field. Those all are OK. I have the needed measuring equipment to ensure that.
Electronics being my hobby since age 7 made me "attack" the circuit board with some confidence. And, as it appeared, there were two capacitors that had been dried out by the nearby hot resistor. After replacing them all the thing started strong again. I also replaced the resistor as it broke because it was attached with epoxy to one of the capacitors.


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