Hmmmm.

The Macap M4 (doser model) I purchased new in Mid-2007 appears to have died tonight. The motor was working as normal this morning and not working all of a sudden tonight - making a quiet hum only when switched on.

The machine has only been grinding an average of 1-2 espresso's worth of coffee per day over the past 2.5 years and I would expect that the motor would have lasted a lot longer than this in a purely home environment, and using strictly as directed, never 'run dry' or adjusted when not running, and with no tampering or 'mods'.

Is this a common or known issue with grinder motors? Is it a matter of replacing some burned out capacitors or perhaps a solenoid?

It's out of warranty (just)...and I'm just waiting to see if the vendor will come to the party before pulling it apart.

That is not very common at all. Are you sure the motor is dead? I'd unplug the grinder and see if I could spin the burrs by hand in both directions. The humm you hear could be a rock lodged in-between the burrs preventing them from turning.

Just a thought...and I hope that is your problem.

The burrs can bind and stop the motor from turning, e.g., detritus in the coffee or sticky tar buildup if you use oily coffees. See Cleaning the burrs of a Macap M4 Grinder. If the burrs do bind, immediately turn off the motor, otherwise the grinder will overheat and potentially damage the armature wiring.

You can skip most of the disassembly steps in that link if you remove the two small screws that lock the worm drive in place. Once removed you can flip the drive back on its hinge & unscrew the entire upper burr assembly without removing the hopper or adjustment ring.

This can happen if the grinder is adjusted finer without running the motor. A bean can get lodged and stop it.

If it isn't a frozen burr, the hum usually indicates it's the starting capacitor, not the motor.

Thanks for the replies. I hope this is a starting capacitor issue, which sounds simple to replace (I expect) rather than the motor.

As stated, I have never adjusted the grinder 'dry', so don't anticipate that this has happened....but still, I'll also obviously check for free movement of the grinding wheels (power unplugged!) before hauling the motor / capacitor out.

With the grinder empty and the burrs backed well off, the motor should start.

Check for loose / burned connections before totally disassembling the unit. The wiring is all on the bottom end.

Well - whaddya know - it WAS a jammed bean in the works. Backing off the grinding burrs allowed the motor to spin again, and all is well.

Needless to say I'm thankful it wasn't the motor - and took the opportunity to give everything a thorough cleaning while I was in there. That first shot of espresso sure is tasting sweet right now!!

I am glad you found such a simple fix for your problem.

-C