I can't figure out why my Williams Ten Pins won't score correctly. The two videos linked below demonstrate the problem:
https://1drv.ms/f/s!AmsGX6AtNo1mm7xBOEJrO14YVI5gqQ
In the videos it's scoring a strike for each frame, so it should advance the 10-reel 3 times at the end of each frame.
In the first video the 10-point bell is enabled and the bell sounds 3 times each frame, but the 10-reel only advances twice. The bell leaf switch is located on the same relay as the 10-point reel, and I can visually see the reel switch connecting and sparking 3 times, but it only advances twice.
In the second video the 10-point bell is disabled by inserting a piece of cardboard between the leaves of the bell switch. Now the reel advances correctly 3 times on each frame. Why would disabling the bell "fix" the problem?
The second video also demonstrates another problem: The 100-reel sometimes advances when the 10-reel hits 9, then again when it rolls over to 0. This happens occasionally whether the bell is enabled or not.
The weird thing is none of these problems occur when I trigger the 10-point relay manually: The bell chimes and the score reels advance correctly every time.
Has anyone seen anything like this before? I'm wondering if the voltages are off, but I don't have documentation to check against. Another theory is the 10-point relay is weak or oscillating and creating erratic switch contact.