I have a Altec Lansing iMT620 unit which needs to be disassembled for repair. Has anyone done this? I think that the front...

I'm suggesting that the user keep his/her hands in their pockets during the analysis phase. Make sure that the power is disconnected and the high voltage cap is discharged before doing any disassembly or replacement! Under those conditions, a microwave oven is completely safe to work on. I mean, after almost 40 years in the business, I'm still here!! JIm

Try to find where the arcing is coming from by viewing th e inside of the oven "cavity" while the problem is happening. You can safely run a microwave oven with a container of water inside (something like a margerine container for example). The arcing usually indicates that a component is breaking down and carbonizing, therefore becoming conductive and sparking while the oven is on. It is common for the "waveguide cover" to do this. The problem is caused initially by food debris, etc. becoming stuck in the crevices of the cavity and then becoming conductive. When you locate what is arcing, you will know what component needs to be replaced. Jim