Update
Updating database... Please wait.
Monday 1 January 2018 at 21:49
It can be in the backbox too. There is a group of wires that go from the cpu to the aux power supply. Another group of wires that go from the aux power to the innerconnect board. Lastly a group of wires that go from the coil innerconnect board to the p/f coils.
Source: http://pinside.com/pinball/forum/topic/whirlwind-system-11-suddenly-wont-boot#post-4153331