20 Most Recent Dremel Multi Max Kit Questions & Answers

Question edited into written English. Question moved from Laundry Dryers. Duplicated deleted, refresh page to see your question. Probably a broken shear pin or gear. Check out the tear down video. https://www.google.com/search?q=dremel+multi+max+mm20+doesn%27t+oscillate ..

On a 4000 there is a thermal fuse at the base of the motor from the brush housing. They are cheap to replace. these are replacing fuses on alot of electronic devices. the fuse is a microtemp g7f01 110c.

I took mine apart due to the same reason. Seems like the yoke that fits over the drive bearing is worn or bent to oversize so that it doesn't make a complete rotation. Hence, a very small or no cutting swath. You can replace the drive head for about 22 bucks plus shipping, (dremel parts) or go to Home Depot and get another one for 70 bucks plus tax. Or do as I did and go to harbor freight and get a Chicago Electric multi tool for about 30 bucks. It works fine. I'm not a professional and don't need a 200 dollar one.

The speed control pot has become dirty from eating it's own dust. Try squirting electrical contact cleaner into the slot in front of the pot. Guard your eyes!! Rotate the pot from end to end a few times and repeat if necessary. Let it dry before applying power.

There should be a second brush. Look along the motor - you're looking for a spot where the armature (the part that rotates) is surrounded by a ring of little straight copper-colored bars. That's the "commutator" section. The brushes run against the copper bars. Look on the outside of the plastic shell - there may be two large plastic screws, one on the outside of each shell half, right about where the commutator would be on the inside. Those are your brush holder screws; you should be able to change the brushes from OUTSIDE the tool without opening it. Some tools are built without external brush holders like that, but most have external brush holders. If you find external brush holder screws, then track down the second brush and set it aside. It MAY be hanging from the brush holder in one of the shell halves. Unscrew both brush holders and remove them from the shell. Set them aside and reassemble the motor back into the shell. If the brushes are really short, like if they're nearly cube-shaped, then it's time to replace them. If not, try them again. Insert one brush into each of the holes the brush holder screws came out of, and put the brush holder screws back in. Be careful not to cross-thread them. Try the tool. If it still won't run, it's possible that an armature winding has given up the ghost and it's time to replace the tool...

Check and replace brushes as necessary. Also, check that the actual electrical switch is functional. I had to add a drop of crazy glue on the tip of the interior plastic handle housing that supports/puts pressure on the electrical switch to keep it in position. The off/on thumb slider actually extends well into the housing and activates the electric switch by moving back and forth. Over time, the plastic wears and does not plunge the on off switch button. A drop of glue on the tip of the plastic post extends it & causes enough pressure to make the electric switch to function again. Brushes (filed to fit) and glue = good as new Dremel :o)

Not sure about the actual voltage, but the primary power board shows 94 V @ 2A. As this appears to be a variable speed drive, the voltage amplitude should vary depending on the speed potentiometer setting. The most likely culprit is the speed potentiometer. Poor design causes vibrations on the printed circuit board. This induces metal fatigue in the potentiometer terminations at the board. Eventually one or more terminals snap off. You could try removing the pot and connecting the wiper termination connection directly to the relative end for full speed? This is assuming you want it to run at full speed? Failing that you could try variable resistance settings and then replace the pot with a fixed resistance for the required final speed?

The most likely culprit is the speed potentiometer. Poor design causes vibrations on the printed circuit board. This induces metal fatigue in the potentiometer terminations at the board. Eventually one or more terminals snap off. If you are a whizz with a soldering iron you could remove the pot and then solder a new wire/s onto it and fasten it back onto the board?