Whirlpool 20" No Microwave MT4110SK

I have had it for a month now and have had no issues. Everything I have heated in there has cooked well. I use it mostly to reheat items or defrost meat.

I had this machine for 5 years; at first it worked great. After four years the turn table wheels started getting this nasty residue on them; I pulled it out and cleaned but it just happened again and again. Finally the wheels wore thru the floor of the...