Quoted from pindoc1:However, I still have an underlying problem that was present with the original CPU. There is a constant flame like flickering of all the displays, all of the time
Do the displays always shows 0000000 and cannot start a game?
If so, sounds like it has an open slam tilt switch.
Refer to 4.16
http://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#5th_Generation_CPU_Board_.28System_80B.29