Also, check the switch on the double bonus relay with the yellow wire and red/green wire. This should be a normally open (NO) switch during the start of the game. If it's out of adjustment and in the closed position, it will cause the double bonus relay coil to be constantly energize... You can block off that switch with a piece of paper or tape, and if you're still getting power to the relay, then power is coming from another source. Probably from a ball index relay switch and/or the ball count unit.

If there is an issue with the ball count unit rotation, then this could send power through the ball index relay. Make sure the ball count unit is operating properly by manually advancing it by pushing in on the ball advance solenoid plunger...