Williams Liberty Bell. Game does not match and no knocker. Knocker works, match unit cleaned with scotchbright, alcohol, then thin layer diaelectric grease. Looked at Rolf Martin’s 2017 extensive help for pinballman3 on Pinside, tried jumping as noted, nothing works. Match lights have been coming all the time but after I cleaned the on/off match adj jack, match lights don’t light any more when game over. Appreciate any help.

Cleaned all plugs, checked wires - good resistance. Ball in extra ball mode, no. match adj is on. Will check outhole relay, extra ball relay and ball ind. relays. Machine has been working great for some time. Might be my imagination but it seems when this problem occurred, the match unit became much louder. A loud click when advancing. Put jumper wire from left side of credit unit step up to Y-BLU wire on score wheel and knocker popped. No knocker sound when jump from left side of credit unit step up to all points in between so suspect match unit is problem. Good resistance showing on all connection between these two points. Thanks

Yes, that's the piece. I'm pretty sure it's not broken because it alternates lighting the "spinner scores 1000's when lit" lights on playfield when I manually advance it. It also advances during game play as it should. Thanks

Put plug in credit (not extra ball), nothing. This machine has been working fine for some time and I did not do anything with that adjustment. Thanks

Hmm, I see what you mean about number match adjustment on mikala's reply. Can't understand why this has been working fine while plug is in extra ball position. I'll play some more with the plugs. tx

plugged into credit, nothing. Traced resistance on both wires from credit/extra ball plug. Also cleaned and checked gap on outhole, extra ball, and ball ind relays. tx

Cleaned (again) m/b game over relay switch (at A 2), good resistance on switches. Also check all wires from g/o switch to 15 amp fuse, credit unit open at zero pos sw, and GREY-O wire to game over lite and no. match adj. jack, all good resistance. tx

no match lights!

will do...

Will do, tx

Jumpered from brown thru g/o to GREY-O on "no. match adj jack". It awarded a free game (forgot to see if any lights were lit). From brown to B-G on other side on no. match adj. jack. Awarded a free game (again, forgot to look at lights). Then jumpered from brown to W-G on the match unit, it burnt the zero trace on the match unit board.
(This is all after the burnt trace): Did multiple tests for all matchs:
90 awarded free game and lit the 90 light
20 awarded a free game and lit the 20 light
10 did not award a free game but lit the 70 light
All others did not award a free game and no lights.
Will fix the trace tonight and see what happens.
Thanks for your help!

Fixed trace. Just to add to complexity (unfortunately), when replacing the plastic wheel on the light side of match unit, it slipped off so lost exact position. Therefore, I have tried all 4 positions and I think it's back where it should be. Is there any way to verify the correct position based on the random match problems I'm having?
More testing (all after trace fixed), pretty much the same as last time. And, getting some random results:
00 – test 1: no free games, no lights; test 2: no free games, no lights;
10 – test 1: no free games, “00” light lit; test 2: no free game, no lights;
20 – test 1: free game, no lights; test 2: free games, no lights
30 - test 1: no free games, “30” light lit; test 2, no free games, no light;
40 – test 1: no free games, no lights; test 2, no free games, “90” light lit;
50 – test 1, free game, no lights; test 2, free games, no lights;
60 -test 1: no free games, no light; test 2: no free games, “01” light lit;
70 – test 1, no free games, no light; test 2: free game, no light;
80 – test 1: no free games, no light; test 2: no free game, no light;
90 – test 1: no free games, “20” light lit; test 2: free games, “20” light lit.
Thanks