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Tuesday 10 April 2018 at 05:08
Just checked pinrepair's guide for Bally mpu boards, and here's what it says:
Sixth Flash Completed*:
The Fakers Guide: a sixth flash means the PIA at U11 (6821) and the U12 timer (5550 chip is good. No sixth flash means either PIA U11 (6821) or its socket is bad, or the U12 (555) timer is bad. Lack...
Source: http://pinside.com/pinball/forum/topic/someone-with-working-granny-and-the-gators#post-4330226