Quoted from creepykenny:thanks! i have done that, the blanking signal (high) is present on the driver board - monitoring pin 37 of the interconnect with a logic probe shows on power up signal transitions from zero/nil straight to a steady high - no low signal is present on the driver board
the coils are firing before the high signal appears - while there is no signal being sent from the MPU, so am i missing a constant low on the blanking line that should be present when power is turned on before MPU boots?
i feel like i am, and with out the low signal the coils are firing .. since if i understand how it works a low signal on the blanking line prevents the coils from firing?
i could easily be wrong tho
This could very well be a case of the indeterminate nature of inputs not turning on in a known state - (like the Gottlieb system 80 thunk on powerup, or WPC thunk on turnon)
There's always going to be this type of state on power up until the power is stabilized, unless some kind of separate reset timing type circuit is added (as in, no power to the coils until the power is stable.... something along those lines).
FWIW a couple of my system 4-6 games do this as well. I'm kind of used to it.
