if the machine is dead no power replace both. if the temp sensor fails it will cause the machine to overheat and open the thermal fuse.
the sensor transitor is about 12 bucks from digi key, or you can buy a replacement board for about 200 bucks from GBC.
I fix these machines for a living the 4250 is actually a good machine but its getting elderly.
if your around pittsburgh pa i give free estimates
bob haller service and sales pittsburgh pa 412 366 4906, September 2011
