Thanks to help from Andrew I replaced the missing resistor but still no luck. Found the 5V DC-DC for the outer oven dead! Scrounged around in my box of DC-DC units and found a UWR-5/1800-D48. The original is a UWR-5/4000-D48 but I can't see why they had a 4 Amp unit in there except maybe for high temperature derating. Installed the 1.8 Amp unit dead bug style and after having to do the J2 pin 8 workaround the outer oven came up OK and regulated! Hooked up my antenna and after a while it locked up! HooRay :) After 24 hours the DC-DC units were warm but not hot! Back in business. Cheers, Corby