I patched ours once when it acted up, basically by disconnecting a trouble spot, and it lasted a while longer. But the bottom line was that it was aging badly. Unfortunately it was also an odd sized oven, and the cabinet had been built for it.

Turned to Craigslist and found a guy 2 hours away had one in his appliance store that was special ordered for it's odd size, but ended up not fitting. Got it for something like $200. Maybe you'll get lucky and find something close by.
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Some hunt for racks, some hunt for roasts. I hunt for sheer joy; the aforementioned items are merely fringe benefits.