Hi All,
I have a problem I thought I could sort out but cannot solve.
I have a Space Jam machine whose right flipper is locking on, blowing the 3A fuse, and blowing the Q16 transistor when I hit the flipper button. It is not locking on when the machine initially powers up or a game is started - only when I hit the right flipper button. The problem is not mechanical - the flipper unlocks when the power is turned off.
I have done the following:
Replaced the coil with 090-5020-20T (comes with a new diode). Made sure that the diode's polarity was the same as the old coil.
I have replaced the Q16 transistor with an IRL540N
I have socketed and replaced the U2 IC with a 74HCT273N
Some other clues:
The coil was hot when the fuse first blew and we initially discovered the problem.
The diode on the old flipper coil seemed to test ok.
I don't quite understand the end of stroke switch on these machines. I tested it for continuity. When the flipper is down there is continuity where the wires connect at the base of the switch and when it opens there is not.
For context:
I do not have a deep understanding of electronics, but have been able to sort out most problems with my machines over the years (thanks to threads here!). I have multimeters, good desoldering and soldering tools.
Any advice or suggestions of how to test and track down the issue would be great.