purchased in 1980 something, and working perfectly devine until now. the convection works but the micro-processor does not. there is no heat but there is rotation and sound. how does this happen and what can i do to correct this, if of course i am able. this being a Panasonic Demension3 microprocessor convection oven. purhased in 1980 something. thanks....

m.bozoff, July 2009