You have probably checked this already, but anyways.
If there is some kind of connection between the switch of the first 1 of 911 and the flippers,
or there is a bare/semi-broken wire/solder or something like that in close proximity to that switch that are
in line with the flipper wiring..

I assume that a short in that switch (or its near proximity) could cause the pin to reset, that could
also explain the fuses getting hot, right?

If the short is kind of random. The switch it self is could be worn out, or when the switch trigger closes it
could some times touch a screw or another cord or something like that?

What do you guys think?
/mima