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Tuesday 13 March 2018 at 18:28
I didn't realize that you have the WPC version. There is a board in between the cpu and sound board. I have never seen one before as there is only @ 100 units made. This board maybe your problem too. Can you post a good pic of this board?
Source: http://pinside.com/pinball/forum/topic/problem-with-sound#post-4278656