Washing machine was making louder than normal noise during spin cycle. Thought it was because of an unbalanced load. Now it will fill and drain but will not spin. I removed the front panel. Tub spins freely by hand. Shock dampeners look intact. No LED visible on motor inverter board. Field Service mode will work for knob positions H, C & P but nothing happens with AL, AH or S. Drive belt looks frayed and I noticed a black power residue at the bottom of the cabinet. Looks like rubber or hard plastic. Not sure what to do next.