Hello,
After a month of searching I am finally just gonna ask for help. Finishing up this game. Just having 2 small score related issues.
1.) on player 1 (single or 2 player doesn’t affect it) when P1’s ball drains a mystery 50 points is added, now it’s odd as say for example there are 51 points on the score when said ball drains, it’ll go 61, 71, 81, 91, 01. So the issue doesn’t trigger the 100’s reel to advance as it rolls past the century mark. This occurs all 5 balls P1 only when in 2 player this doesn’t not happen to P2. The game does trigger the 100pt reel to advance normally with playfield scoring.
Here is what I have verified, the 50pts is not coming from the 50 point relay, blocked it’s contacts still occurs, it’s also not the 10pt relay did the same thing there.
2.) this issue happens almost always and exclusively to player 1 ball 3 drain, in single player mode, when that ball drains, P1 gets the 50 free points, which as I showed above can actually set you back. However on this situation 1 solitary point is added to the second players scoring. This does not occur in 2 player.

Any ideas are appreciated…..

In my mind it seems to possible be linked to the reset wheel motor in the cabinet or possible something in the ball unit?

Resolved:
It was in an unlikely spot yet makes sense when you think it through. The scoring reset relay, has 8 switches 4 on top 4 on bottom, each resets a score reel, the switch for the tens unit player 1 was touching had visible signs it has been dicked with before. I gapped it to be open like the others. Scoring issue fixed. Problem was when that cabinet cam motor turns at ball drain it makes a 1/3rd rotation hitting 5 impulse spikes on that cam, since that relay has all open switches and only closes when the coin/credit relay triggers it those switches all get 5 power impulses every 1/3rd rotation of the motor. Since they are open nothing happens except in my case.

A second almost identical scoring issue decided to crop up. Exact same thing swapping from player 2 to player 1. But this time it was doing 5 pts 2-3 on player 2 and the remaining on player 1. I finally found it. On the 5pt relay there was a loose wire. And it it was touching other parts. Soldered it back into place and it’s all fixed now!

It’s a very fun game. I am enjoying it a lot! Those 1-4 targets are sure challenging. I love the clown juggling the extra balls you earn.
As far as if they are hot all the time I didn’t check, I know they are hot when the score motor spins it’s getting 5 impulses but the relay is not closed so the 8 switches on it are all normally open. That relay is activated at the coin door. Just had one that was likely bumped by other repairs in the past and was closed so it was the cause of the mystery 50. Then the mystery 5 started happening but not all to the same player so after I ruled out the same cause, I eventually found the cracked solder on the 5pt relay. All fixed now!