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Wednesday 2 May 2018 at 00:06
There should be another switch on the credit unit, besides the ones you describe. Find the plunger for the advance solenoid and follow the attached lever arm across to the opposite end. The knocker actuation switch gets closed by the opposite end of the lever arm when you manually work the advance...
Source: http://pinside.com/pinball/forum/topic/gottlieb-pioneer-knocker-not-working#post-4373487