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Saturday 31 March 2018 at 12:15
First thing would be to check the connectors//cables - wiggle and see if the problem changes. Remove sound board and check the reverse side at the pins for the cables under magnification. Make sure there are no cracked pins. If no visual indication is found, swap the left and right speaker and te...
Source: http://pinside.com/pinball/forum/topic/data-east-secret-service-left-speaker-humming-loudly-please-help#post-4312407