i have a old 1987 quasar microwave. the control board has been replaced once, now the power button works sometimes, i have been looking for the replacement part but no one seems to have it. i am told the part # in 42qbp3894. i love this microwave even though it is a tank. it is large inside and fits my crock for making greek yogurt. any help. the picture of it is the one on your webpage.