the diode thing actually fixed mine. Dead awkward to get one of the diodes past the big yellow thing but if you use pliers to turn the screw rather than a screwdriver its not so bad. When you're finished, just make sure the diodes are touching the heat sink at one point at least, otherwise, the diodes will heat up too quickly and they will blow and you'll have the exact same problem again! The diodes only cost like £3 or something so its worthwhile to at least give fixing it a go! I got my parts from CPC. Mine's works fine now!
John- glad to be of help, September 2009