I'm sticking this here, because I could not find any instructions on
the web, and google does a fair job of finding googlegroups posts.

The Capresso Infinity grinder (Model 505) is the only motorized
conical burr grinder under $100. Which is why its failure to function
yesterday caused us consternation. Basic troubleshooting revealed
a chunk of plastic had broken off the bean hopper. My beloved wife,
who is the only one to use the grinder, claimed ignorance.

I took off the grounds recipient, and, with the torx bits of my screwdriver,
removed the lower burr, discovering impacted coffeegrounds underneath.
Still did not spin. NB: the lower burr is pushed upwards by three balls
atop three springs. Do not lose these.`

How to remove the housing mystified me, but I found that it was held
on by five tabs, which I could depress with an old butter knife,
allowing me to slide the housing downwards.
The power cord is connected to a terminal block, which in turn is connected
to two blue wires. One blue wire goes to a microswitch, which is closed
when the bean hopper is properly installed. From there, another blue wire
leads to the grinding timer switch. From there, a white wire goes to
a little circuit board with a MZ-23 PTC thermistor on it, and four diodes.
Red and black wires from the motor go to this PCB.

Measuring continuity with a VOM was not very fruitful, so I turned
the timer switch to 10, plugged the grinder in, and manually closed
the microswitch. Success! as the motor spun.

Monday I will try to order a new bean hopper, and perhaps a new
microswitch, direct from Capresso.