By way of an update, the shredder is now operational again.

The model is an ATX 2200 rapid. I took off the back cover, for access to the switches and I also removed the motor, from the front. There was nothing obviously wrong on exam by eye. After a bit of poking around, including poking the motor brushes and spring mechanism, I tested the unit again and bingo- normal operation.

So, no satisfaction in terms of identifying and fixing a specific fault, but the end result is good. My best guess is that one or other of the motor brushes had become sticky and was making minimal contact. Next most probable cause is one of the switches that I removed and fiddled with for a while, before re-fitting.

Bill.