You picked up a game back in Sept '16?

Now we know where the DeLorean went...

Hi Cooky. dont have that pin, but... I would start with the score reel switches. then the player control relays, I think they are AA,BB, etc.
then the player unit. assuming it has them...

Put slips of paper between any switches that have a value of 1 point. One by one remove them and see which one makes the relay lock on. Adjust that switch accordingly.

Hi
CookyJar wrote in post-1 "main issue is 1-point relay ONCE ACTIVATED becomes locked on".
To me this means: A Score-Reel problem.

CookyJar: Question: When You start a game - Do the 1-Point-Score-Drums reset ?
When You get the ball ready to play and You activate a "target worth 1 point" and the 1-point-RELAY pulls-in (and faulty keeps-on pulling): Does the Coil on Score-Drum PULL-IN the plunger ?

Theory: Ball hits a target --- 1-point-RELAY pulls-in - close its "Self-Hold-Switch to keep pulling forever" - another switch on the moved 1-point-RELAY closes and feed current to 1-point-SCORE-DRUM. Score-Drum pulls-in - its plunger is moved - at "end of travel" the moved plunger opens an "End-Of-Stroke" Switch. THIS EOS-Switch is in the "Self-Hold-Circuitry of 1-point-RELAY" - therefore 1-point-RELAY looses power - let go and by doing this opens both "Switches mounted on 1-point-RELAY" --- "Score-Drum let go and 1-point-RELAY can not hold-on with the Self-Hold-Circuitry".

So we need the information "Does the Coil on Score-Drum PULL-IN the plunger ?" Greetings Rolf

it shud be in the middle? of back box.
it has a brown disk on the outside,"you can see it", and some white cams behind it

I agree. Rolf is heading in the right direction. Here is an embellishment:
Start a 2-player game.
Don't let the ball roll on the playfield, but manually actuate both a 10 and a 100 for player 1, ball 1. (Manually click the relay is one easy way.) Do NOT score any 1s!
Drop the ball in the outhole so that the game advances to player 2, ball 1.
Hit a 1-point switch and continue with the analysis suggested by Rolf.
Now you know the difference in behavior between the player 1 1-point reel and player 2's 1-point reel. If the problem is an end-of-stroke switch on a score reel, you'll probably see a difference.
If you can't complete the diagnosis, bring the game! Experts will be available.
.................David Marston

So the 1-point relay is trying to actuate either the player 1 or player 2 1-point reel and not causing that coil to pull in? Now you need to identify the wire color of the wire from the 1-point relay that goes to those coils. Somewhere along that path, it goes through a stepper-unit disc or switch to choose between player 1 and player 2, but if both players behave the same, then the breakage is in the part that they have in common. I say "breakage" because the power is not getting to a place that it should be. Try to follow that wire along its whole route, although the two endpoints would be the main suspects. I wouldn't expect any connectors along the way; everything should be in the back box.

As a separate issue, you seem to have a 50 point switch stuck closed somewhere. Check all the 50 point switches.
.................David Marston

Try Tony D., Dave Metrando, or me. Tony has a team and can pick an available EM expert from that team. If you have the schematic, be sure to bring it.
.................David Marston
(who is wearing his Team-EM shirt today)

Hi,
I also picked up a Mayfair last week, there will be one at Pintastic. I'm looking to take notes on stencils because some jack wagon painted my cabinet tan. My game plays but doesn't score 1's 10's or 100's , love the dual shooter between flippers. You historians should know this is the last pin to have Roy Parkers artwork. It's also an Ed Krinsky design with metal jewel posts. There are only a handful of pins in this era that have this combination .

DQ74