mopar A few of those things I've cleaned/replaced over the years.
The switches in the outhole and ball index relay have been cleaned up and adjusted.
The Ball Index Relay also got a new coil last year. Since it's right up front I've been able to watch it close when the ball rolls over that shooter lane switch and it energizes every time.
For a while I thought it was the ball index because if I put a piece of tape on the shooter lane rollover switch to hold it closed during play the ball count works every time. Makes me think the ball index is releasing too early, but I don't think it's a problem with the relay itself. Not sure.
I looked at D3 and B2 a while back, but these are cleaned and adjusted and seem to work as intended. D3 also tends to make a visible spark when it closes.
I'm going to go back and check two of the things you mentioned more thoroughly; the 100-900 relay and the Extra Ball Relay. I just took a look at the extra ball relay it and it's still a little cruddy. I'll clean it again and might replace that coil too. Thanks a ton bud and enjoy the holiday weekend.