This sounds like the stock fault with this type of hold down/timer electromagnet . The power supply to the control boards (one for each side) is taken off a tapping on the heating element (about24vAC). Unforntunately this rivited contact often becomes a poor contact. There are ways of fixing it, dismantle it and put a nut and bolt through it at the contact point, or insert a small transformer instead. I prefer the later but for the less technical the former. Pity about this fault on such an otherwise brilliant toaster.
Make sure its not joined up to the mains, not even plugged in, if you attempt a repair!!!!!!
Ken J H, January 2010