What typically causes a 'jackpot'?

[Apple Leisure]

I have an AP 112 and the coin mech jackpotted the entire inventory it seems.  Luckily an honest person returned the coins to me, but what is the probable cause?  The mech itself?  Something else?  It happened on a sale I am told.

[AZVendor]

This most commonly is the result of a bad florescent tube in the machine or near it that flickers and causes an indistinguishable electromagnetic input to the logic board.  This can cause a jackpot or sometimes random motors to run.  The bad lamps could be in a nearby machine or in the ceiling.

Another possible cause is a loose coin mech plug or loose connection from the board to the display to the keypad.