oven/broiler control unit

Thermador oven controls worked fine for the first 5 years but in the last 6 months the Bosch control unit has been fried and replaced 3 times. While it is easy to replace these units it is a costly exchange at $200 a pop. Appliance parts pros have been helpful and replaced a unit (part #ap2836528) under a warrentee. What in the stove is causing these units to short out within two months of being replaced? Any help would be greatly appreciated.