Hi John
This is caused by a faulty regulator on the power board. The regulator gets very hot during normal operation and is on a completely inadequate heatsink. It usually lasts two to three years then causes problems like continuous self checking or fuse blowing.
It's easy to fix and you can obtain parts online, but you need to be able to use a soldering iron and pull out the board to repair it.
Cornish Tekbabe, March 2008
