Has anyone actually worked on any of these 1930 - 1950's Evans console slots?

Here is one that I restored two years ago.  The 5th and 6th horse will payout the correct amount, but not all the time. 

I took everything apart, cleaned, rebuilt, etc.  I traced the wires from the coin switches all the way to the spinner, after a failure, and I have continuity between every point.  I'm leaning toward a bad solder joint, bad wire, or vibration from the coin section as the coins pass through the head opening up the coin switch. 

Just wondering if anyone has had a similar problem with these machines.  If so, what did you figure out??

Also, how often did you get a Winterbook??