Yeah, it's possible H4 isn't (yet) touched by the software, but it's supposed to be high on reset. H4 controls if the 100 Hz timer causes an IRQ 6 on the 68020 (it always clocks TIN on the PIT, and if H4 is low then the IRQ 6s occur).

Last edited by R. Belmont; 11/28/16 03:27 PM.