I have a PANASONIC NA-F110GS WASHER for the past 6 years. Recently, when I put in a small load, during the rinse cycle phase, when the machine starts to turn, the load gets pushed to one side of the tub and the tub becomes unbalanced. Then the machine stops with a continuous beep. After I re-start the machine, the rinse cycle phase starts from the beginning. What do you think is the fault? I did not have this problem earlier.