casiotone MT-35 FRIED??

Isn't that the escensce of circuitbending?...

To go to the bounderies towhere no one has ever gone and sqeeze the last bit of juice out of the tormented soul of a helpless piece of toys.

if it's fixable depends on the professionality of the equipment.
Ther could be a fuse or the voltage regulating transistor (A flat black thingy with three legs,probably mounted on a aluminium cooling block ,almost directly after the power input) that is broke.
However the last are mostly protected against overpowering and shortcircuiting.
If you managed to overpower some IC's (Black blocks with lots of legs on it) then you were withness of a fairly unwitnest aspect of the live of a piece of electronical equipmend.....DEATH!

I hope you don't greaf to long.Live is to short.