One of the rivets on mt Duotron payer unit is badly warm and is causing problems. This particular rivet in ibvolved with third ball/last ball.
1. When the rivet is warn down the machine defaults to five balls per game even though it is set to three balls per game.
2. When the rivet is "repaired" with normal solder the machine works perfectly giving three balls per game.
3. As the "repair" wares away the machine is intermittent at three or five balls per game.
I repeat the "fix" and all is good again for a couple of months. Is there any way of carry out a proper lasting repair on this?