Hi mrm_4
the basic stuff is in the schematics at "10-E/F" --- as get no replays at all: I suspect the Adj-Switch --- see here: https://www.ipdb.org/showpic.pl?id=2110&picno=64797 - on top of the plug (upmost in the picture) - from left to right or right to left runs current for stepping on the ball / players - and on the second wire on the plug from left to right or right to left runs current to make replays - to make the Replay-Unit-Step-Up-Coil to fire. Greetings Rolf

Hi mrm_4
in post-6 You write "Still not getting high score credits" --- what about "Special-Credit" ?, what about "Number-Match-Credit" ? Greetings Rolf

Hi mrm_4
when You plug-in (maybe You have a toggle-switch to toggle-on) - press the left flipper button and or start a game - Does Your Lock-Relay pull-in and stay pulling ? I assume "Yes" - write if "No".

See the first JPG - I would like to test "marked orange wiring". Have the Jones plug plugged-in, unplug the main power cord. See the second JPG, at "my B - also my C" we see the Kickoff-Switch. See "at my B": One of the solderlugs on the Kickoff-Switch has soldered-on two wires-yellow. Clip-on a Jumper-Wire at Lug-yellow on the Kickoff-Switch --- take the other end of the Jumper-Wire near the "my N, the Jones-Plug" - lay the free end of the Jumper-Wire on wood - not touching metal.
Plug-in, (toggle-on) start a game --- now hold the Jumper-Wire on its insulation, hold it near the free end - touch and pull-off the free end of the Jumper-Wire - onto the connecting short blank wire "Jones-Plug, I have marked red in the first JPG". Does the Replay-Counter step up ?

(((In a running pin at a time there is made connection "wire-yellow through some relays, wires - coming-in on 'my marked-blue wiring' to the Jones-Plug"))) - and YOU have made a direct connection with the Jumper-Wire. Greetings Rolf
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Hi mrm_4
to post-12: Maybe You are at the cause of the fault (?) - see the JPG in post-10 --- with the test Jumper-Wire tip-on AND PULL-OFF*** You test for connection along "my marked orange wire, connection". When the Replay-Unit does not fire: Fault detected.

Lets do the Jumper-Wire-Test once more - this time using the transformer-lug-yellow. Unplug the main power cord --- see the JPG at "my H" - two wires "yellow" are soldered-on. Clip-on the Jumper-Wire at the transformer-lug-yellow - MAKE SURE the gator-clip is secure - cannot fall-off, cannot get in touch with another solderlug on the transformer (otherwise You would create a short, making a fuse to blow) - the other end of the Jumper-Wire lay on wood - not touching metal. Unplug the Jones-Plug (JPG at "my N").
Plug-in the main power cord, start a game --- tip-on AND PULL-OFF*** the Jumper-Wire at the left socket at "my N", the "L2-Position-Socket" - then tip-on AND PULL-OFF*** at the "R2-Position-Socket" --- the Replay-Counter should fire "tipping-on at L2-Position-Socket". Greetings Rolf

P.S. PULL-OFF***: As You do not want to have the coil fire permanent for a long time.

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