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Sunday 25 February 2018 at 12:31
Quoted from spiroagnew:I should probably swap in the 680ohm resistor and see if that makes a difference, right?
R1 is specified as a 600 ohm resistor (check the schematics). They are however harder to find so your boards that have 680 ohm resistors have had it changed (commonly accepted replacement...
Source: http://pinside.com/pinball/forum/topic/bally-35-mpu-bootstability-issues#post-4249627