Looking to take the cover over a 3 year old Kenmore countertop m/w. The screws in the back appear to be 3mm hex but they have a nub in the middle that keeps the hex wrench from seating. Would need an indented hex wrench to get past the nub. Told a friend; he thought Grainger, Sears or Home Depot would have it but found nothing. Is there such a tool? I am interested in fixing if the problem is just the $3 fuse (clock works but no power otherwise). If it is anything else, I'll just go shopping.