As Wil said, this is sometimes a door lock issue.
I had the exact same problem on mine, lean on the door and the lock would then allow the machine to start (been like that for several years.)
The other day though the door lock light wouldn't stop flashing (like the door wasn't closed properly as before) it seems like a duff lock switch has finally done the control module in, there's a small section of PCB track near the right board connector (as you look at the front of the machine) with a small bit burnt away, bugger!
I'll try for a repair, but if no joy then a new board it is!
I had to replace the motor brushes a couple of years back aswell.
Oh well, at least you CAN get the parts for these machines!
Chris.
January 2015