HB wrote:#3 The upper assembly has been cross threaded and cannot go any farther down.

That was going to be my contribution to this troubleshooting exercise. Crossthreading is pretty common.

brad

Have you tried grinding some white rice?

If it spins the wrong way, the motor is shot. Not the cap, not the wiring, not the switch, not the mills, not the old dirty coffee, not the threads being crossed, not the fact you are in the northern hemisphere . . .nada.

If it doesn't spin the wrong way EVER, blame the coffee.

Until you can determine the direction of the rotation under load, all speculation is futile.

Rice won't fix the motor either. Sorry.

I was just wondering if it COULD grind rice, not thinking it would fix the problem.

mteahan wrote:If one of the windings in the motor is shot, it will spin the opposite direction when under a heavy start load. It spins the correct direction on occasion, but under any load it runs backwards. This is a wiring fault and you are better off recycling the motor. They are a bitch to replace and new motors cost as much as a grinder.


Michael

Having successfully had 2 grinder motors "rewound" it was a pain to find someone to do it even with an abundance of these old guys that repair motors around Hong Kong. Also on a mazzer the stator is a press fit into the casting and just awful to take out. The grinders I repaired are 40 years old so it was worth the expense and hassle.

These motors are just miniscule so repair is tricky. I walk past a motor repair shop down by my office every day and the size of some of those industrial motors is just mind blowing.

I just received a vintage (70's) mazzer jolly in good condition, and once unpacked ad put to work i found to have the same problem reported in this post (actually, i found this post after typing in what my problem was)

Burrs are spinning in the right direction and look in decent condition, the grinder however is not able to grind fine enough for espresso and spits out VERY coarse bits of coffee. The collar can be tightened down but it either starts ringing, as a prelude of a burr on burr accident, still giving out as a result huge coffee fragments, or (tried with rice) makes a deafening noise and even stops.

I was curious to know what happened with luigi's grinder and how (IF) he solved the problem.

My humble diagnosis is that burrs are not perfectly parallel to each other and coffee tends to exit from the point where the larger gap is. Then, it rings because burrs are touching on one side, but gives out big chunks because the milling surface is uneven. It should be something microscopic however, because i can't see anything spinning noticeably off center or unevenly

Damn upgradeitis. I should've stuck to my anfim best

Any advice is VERY welcome. Thanks in advance

I assume you put new burrs in? If not, that would be a must.

HB wrote:
PS: I don't think this is the cause, but have you checked that the burrs are properly seated? From the photo it appears the screws on the bottom burr aren't properly seated. It's probably just the camera angle...

Looked like that to me as well

I also bought a used Major from the same guy in CT and I also had the same problem. Turned out that the burrs were to blame as the new set was able to grind to a very fine powder instead of big chunks.

I PM'd luigi a couple of months ago about this and replied that he had ordered a new set of burrs. Haven't heard from him since though.