On mine, the thermal fuse in the former windings failed (150 degrees c) causing the fan to fail and the oven overheated and blew the main thermal fuse (157 degrees c 10a). If a thermal fuse fails in the former windings then you need to replace the fan motor. You can try to replace both thermal fuses but this in the large is considered unsafe. Transformer fuses blow for a reason: there could be a partial short in the windings.
John UnClever, August 2011
