Hi Bob, due to the age ,i cannot find the model on my disc.Is it an analogue clock If so it is more than likely this that is giving you the hiss.You can always turn the oven off, take off the top plate and pull off a wire on the timer.Isolate the wire then turn on.If the hiss stops then you will need to replace the timer if still available.If it is electric fan assist, when off this is the only moving part. Hope this helps,All the best.
FOXY, August 2008
