I dont like to debug anything with the pf removed. It would seem to make sense to do this but there may be logic messed up in this case.

But normally a scoring relay locking on.... if something is scored, the relay closes and then pulses the reel solenoid to advance, once the reel advances the end of stroke switch on the reel releases the scoring relay, a mini feedback loop.

Other causes, other than the usual "gapped too close pf switch or rollover" then we see the spacer of one of these contacts bend over to the wrong side, ie the contact is gapped open but the middle spacer widgit is toching the wrong blade. It gets the best of use 80% of the time. The slingshot contacts are best/worst for this.

Ken

If the 100 reels aren’t opening the end of stroke switches the relay will stay energized.

The Fellas are referring to the set of contacts that are open when the
Score Reel's plunger is all the way in. That set of contacts breaks the
circuit to the hold on the Score Relay.
Is it doing it to both Players? If not, almost certain it's that Player's Score
Reel's EOS set of switches. If it's happening to both Players, it lessens
the chance, but still could be (on both Player's 100 Score Reel)..

EoS switch function is NOT used during reset, Nor are the scoring relays...

If you have made it so the L relay switch you have circled on the schematic can no longer make contact, and as a result the L relay no longer locks on, then it is 100% certain that the problem is with the EOS (end-of-stroke) circuit for the L relay.

The main purpose of the L relay, and its EOS circuit, is to act as a pulse-stretcher to ensure that the selected 100 point score unit advances properly. Here's how it works. Let's imagine there is a fast-moving ball that briefly smacks into a 100 point stand-up target on the playfield. If that stand-up switch was wired directly to the coil of the 100 point score unit, the electrical pulse to the coil would be so brief that the coil would not be energized long enough to operate the mechanical drive arm to step the score unit to its next higher number.

So, to avoid this problem, the stand-up switch is instead wired to the L relay. The L relay is very responsive, so it is able to close fully from the very short pulse from the stand-up switch. The switch you circled on the schematic is the relay lock-in. Once the L relay closes, that lock-in switch keeps the L relay energized. A different switch on the L relay provides power to the selected 100 point score unit. The coil of that score unit, energized from the L relay being locked on, pulls the drive plunger all the way in. Once the drive plunger has pulled in far enough to ensure that the score unit will mechanically step to the next number, a small finger on the drive arm opens a switch (the EOS switch) and the opening of that EOS switch cuts off the power to the lock-in circuit, allowing the L relay to drop out again. The drive arm then returns to the normal position via spring power, advancing the score unit. In this way, a short pulse from the playfield stand-up switch has been "stretched" into a long enough pulse to ensure the score unit advances.

Note that on your schematic, there are two EOS switches in this circuit, one mounted on each score unit. These are shown on the schematic to the right of the lock-in switch you have circled, and they are marked "On add 1st player hundreds unit" and "On add second player hundreds unit." These two EOS switches are wired in series, so if either one opens, the power to the L relay coil (via the L relay lock-in switch) will be cut off.

So you probably want to check these EOS switches on your score units and see if they are opening correctly. Note that it's unusual for this circuit to fail in this way. Usually these EOS switches break off such that they are always open, so that the relay never locks on properly. As pinhead52 points out, you may have an unusual short of some kind at the that is keeping the EOS circuit active.

- TimMe