MPC battery issues

I started up my ol MPC500 after a little while of disuse, and to my puzzlement when the power cable came unplugged it just turned straight off. I replaced the batteries with fresh ones but this kept happening. It wouldn't be a problem if the cable didn't keep jiggling just a bit loose and resetting it. >_> Any suggestions on what the problem might be?

are you sure that all the batteries are in the battery compartment tight/properly?

Are they dollar store batteries?

Dont be fooled by those "Panasonic" mofo's

am i tripping but don't all the mpc500's do that? mine does!
if my power lead moves the machine restarts. very annoying but i thought they all did that? i have very good batteries in the machine but still like to run of power adapter if possible.
i have issues with my batteries moving so i put a bit of folded paper in the battery compartment and they don't move at all now so i can bang it hard as i like.