If the Reset relay is stuck activated when this happens, make sure all 8 of the Score Unit "0" Position switches are opening.

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Find the 0 position switch on each score reel and check it like any switch (below). You could even put pieces of paper or cardboard in each one and see if that makes any difference.

For a switch to work 3 things are necessary:
1) When open, there should be a small space between the contact points (duh)
2) When closing, the long blade's contact point should push the short blade's contact point enough to move the short blade
3) The contact points should be clean, which they usually will be if #2 is happening