If the flipper is going up as soon as you turn it on ( before pressing the start button) then it is one of 2 things
A faulty transistor or IC on the fliptronics board or
A bad connection on the ribbon cable
Try removing and reseating the ribbon cable that goes from the CPU to the fliptronics board ( top left ribbon cable) on the CPU and the fliptronics board
If this doesn't fix the problem then it is a fault on the fliptronics board.

If it only goes up after pressing the start button then do what strange ways has suggested
I assume the machine is a Johnny Mnemonic.