For your endless 5th ball issue, check for a broken jumper wire between the double set of wiper blades on the ball count unit wiper. This jumper wire often breaks off. The double-set of wipers must be properly jumpered so that they bridge the set of rivets at the last ball position. This circuit is what trips the game over relay.

The jumper wire for bridging these wipers was known in the coin-op industry as "pig-tail" wire. It is a very flexible braided copper wire. You can't use regular wire to bridge the wipers because the stiffness of the wire will bind up the wipers and they won't ride freely over the contact rivets. In the worst case scenario, the wipers will start cutting grooves into the rivets and that is something you really want to avoid.

It's tough to find pig-tail wire these days, but an easy replacement is to use some thin solder wick (the yellow spool size is my preference). You need to soak the solder wick in alcohol for several hours to wash out the majority of the embedded flux. Don't try to use solder wick as pig-tail wire without soaking it in alcohol first, as the flux will cause the braid to wick up large amounts of solder (after all, that is what it was designed to do) and the wire won't be flexible.

- TimMe

Hi Rolf - In the USA, solder wick is another name for de-soldering braid. They are the same thing.

Yes, I have been using this braid for years as pig-tail wire. I use the .050-inch width (also known as #2, also known as the yellow spool). I buy a spool just for this purpose, remove the entire 5-foot length of the braid from the spool, and soak it in alcohol for 3 days or so. Then I dry it off, wind it back on the spool, and mark the spool as pig-tail wire. One spool usually lasts me a year or two, but I do a lot of EM repairs.

- TimMe