Imp-A is a NO switch. Have you gotten in, cleaned, and verified that it is making solid contact? Visual is not enough.

Hi amymcg
we do look at the problem "Sore-Reels don't reset" - Yes, Score-Reset-Relay must actuate - actually toc, toc, toc ... actuating rhythmically while the Score-Motor is turning - AND within this time the Reset-Relay must be pulling constantly.

I do not really know how far the "Start-up / Reset stuff" does get - so first I would like to know what happens when You "Toggle-off the main power switch - then toggle-on the main power switch - then (have Credits on the Replay-Counter) press the Start-Button / Credit-Button" - does the Replay-Relay actuate - does the Coin-Relay actuate, does the motor starts to run, does the Reset-Relay pull-in and stay pulling ? Well, what happens when You toggle-on, start a game ?
(Before looking at the Score-Reset-Relay to actuate we must have the Reset-Relay constantly puling and the motor running.) Greetings Rolf

@amymcg,
It is no longer a mystery relay - you have identified every other relay in the entire machine. By process of elimination, it is the Replay Relay. Plus, it is supposed to activate momentarily when you push the start button.

Hi amymcg +
the pinside officials do not like us to cross-post but the whole topic I started is also about start-up of Wms San Francisco - and here https://pinside.com/pinball/forum/topic/game-relay-game-relay-what-for-williams-san-francisco-#post-5927522 we see Your "Match Unit" in the lower left corner of the first picture - the schematics has some drawings at (area) 19-E, 19-F, 19-G. In post-5 You write "plug-in, toggle-on ... CHANGE-Relay activates". During play the Change-Relay often changes from Non-Pulling to Pulling to Non-Pulling to Pulling etc. - it changes every time when a ball makes ONE-Point. So accidentally / by chance the Change-Relay could pull-in when You plug-in, toggle-on - but I believe to read from the schematics that the Game-Over-Relay beeing in state "Game-Over" should have a switch open so the Change-Relay only can pull-in after a game has started (because when starting a game the Game-Over-Relay changes position - comes to "In-Play" position, closing that switch so by now the Change-Relay is allowed to pull-in). Before troubleshooting on Score-Reset-Relay not working I wold like to look at "Game-Over" / "In-Play". Here https://www.ipdb.org/machine.cgi?id=2049 on none picture I see the text "Game Over" in the backglass - here https://www.ipdb.org/showpic.pl?id=2049&picno=62551 not the complete Backglass is shown,
questions: When You plug-in, toggle-on - do You see somewhere on the Backglass text "Game-Over" lightet ? --- when You plug-in, toggle-on - are the Score-Drums of Player-1 AND Player-2 lighted ? or ONLY Score-Drums of Player-1 lighted ? or ONLY Score-Drums of Player-2 lighted ? or no Score-Drums lighted ? All written above is my concern "Game-Over or In-Play ?".

To "Score-Reset-Relay does not actuate" - I look at the picture in Your post-1, "marked green, number '4' " and (I believe) text: Jumped from Impulse motor switch to Reset Relay direct with one clip - This works and Score-Reels reset. Question - You toggle-off the pin, unplug the main power cord - You install "Jumper marked green, number '4' " permanent - You then plug-in, toggle-on, start a game - question: And the pin starts, resets the Score-Drums ? You can play and start new games with just this Jumper installed ?

A general remark - when we talk about "whatever-Relay" activates - we better say
"whatever-Relay" pulls-in and immediately let go / quit pulling
"whatever-Relay" pulls-in and after a short time it let go / quit pulling - the Score-Motor does run at that time
"whatever-Relay" pulls-in and after a short time it let go / quit pulling - the Score-Motor does NOT run at that time
"whatever-Relay" pulls-in and stays pulling for (and detailled how long)

You write in post-5 "... Coin-Relay activates ..." - in the schematics I See "Coin-Relay activates AND STAYS active until the turning Score-Motor opens a switch on socalled-cam-5 which actually is the sixth cam" - well, in a running San Francisco the Coin-Relay pulls-in and stays pulling until the Score-Motor has turned almost 180 degrees --- question: Your Coin-Relay activates and stays activated how long (in relation with the Score-Motor making a turn of 180 degrees) ? Greetings Rolf

Rolf and Amy,
Taking a quick look at the schematic, in this particular game, it looks like the Coin Relay should stay activated (pulled-in) until all the score reels zero out. It is held-in by one of it's own switches and a switch on the Game Relay. The 2nd time you press the Start button it will pull-in, but then release near the end of a single score motor cycle because the Game Relay (on the trip bank) has been re-latched and it's switch is now open. So, I would start out by looking for a continuity problem with the hold-in circuit for the Coin Relay (specifically the Coin Relay hold-in switch and Game Relay switch).

Your problem appears to be in this circuit (unplug the machine from the outlet - 110v circuit !!! - and check for loose wires, clean/adjust the switches, etc.) :
pasted_image (resized).png

Edit: As for the Game Over light, it could well be a bad or dirty socket - it could also be it's switch on the Game Over Relay (check that it is clean and properly adjusted for good contact when that relay is tripped).

Hi amymcg, sudsy7
today in Switzerland we had "switching from daylight-saving-time (ds-t) to normal-time (n-t)" --- it is hour (00:45 ds-t) 23:45 n-t --- time to go to sleep. Greetings Rolf

Hi sudsy7
thanks for Your post-7 with the JPG. You are right - the Coin-Relay must stay pulling much longer than I took out of the schematics --- grumble - from later Williams-Schematics I am used to have a dot marking a connection - so I faulty thought: Coin-Relay stays pulling until Score-Motor-Switch-on-Cam-5 opens ...

Hi amymcg
to Your question in post-13 - we actually look at "Your JPG in post-1, marked green jumper": Yes, such a Jumper we can set permanent (to set it we of course toggle-off, unplug main power cord) - Your "marked green Jumper" connects solderlugs that have a direct connection in the schematics. So Your "marked green Jumper" actually is "a set wire to make sure that a permanent connection in the pin truely is functioning".

I allow myself to show Your JPG from another topic here again - see in the lower right corner: I have "marked green" the topmost switchblade on the rightmost switchstack / Motor-Cam. Many Williams-Pins have there the so-called "Score-Motor-Self-Hold-Switch". Please wear rubber gloves / use an wooden stick (Safety Reasons) --- play a bit - the pin is plugged-in, toggled-on, a game has started, Score-Motor is not running --- wear rubber gloves / use an wooden stick - gently press down this (my marked green) topmost switchblade on rightmost switchstack / Motor-Cam - gently press down a bit, after about half a second "let go" - what happens: The Score-Motor will start tu turn - turns for 180 degrees (half a revolution) and the stops.
The reason I ask You to do this "press down and let go after half a second": When we will do testing - we will need to have the Score-Motor to do a turn of 180 degrees --- the "press down and let go after half a second" is such an easy way to make the motor to make a turn of 180 degrees. As You do this by now: Besides the motor turning - nothing is happening, by now I just want You to learn "press down and let go makes the Score-Motor to turn". Greetings Rolf

0San-Francisco-pinside-mech-panel-small (resized).jpg

Hi amymcg
thanks for Your post-15. I am surprised that Your Jumper*** does affect scoring.
It is awful we live in different time zones - for me it is time to go to sleep. I will brood - and write by tomorrow - probably doing another test.
A real problem to me is: Your (JPG in post-1, marked green jumper") jumper*** --- all such Jumper*** we can set permanent - Your "marked green Jumper" connects solderlugs that have a direct connection in the schematics. So Your "marked green Jumper" actually is "a set wire to make sure that a permanent connection in the pin truely is functioning" AND such set wires / jumpers*** to help on an existing wire cannot affect the behaviour of a pin. Greetings Rolf

P.S.: Great - You can make the Score-Motor to do a turn of 180 degrees - whenever we want - / whenever we need a turn of the motor.

Hi amymcg
the pin is so dangerous - I do not want to proceed in stuff "maybe not needed" - so I ask (first): Please give a detailled description of (mentioned in post-15) ... the machine resets, but it messes with the scoring ... - what exactly happens ? Greetings Rolf

Hi amymcg
You know how to make the Score-Motor to do a turn of 180 degrees (pressing the upmost switchblade on the so-called INDEX-Cam on the Score-Motor).

Jumper mounted - You start a game - play a bit, take the ball out, lift the Playfield - NOW You make the Score-Motor to do a turn of 180 degrees - question: Do the Score-Reels reset ? Greetings Rolf

Hi amymcg
it is frustrating - I seem not to get solid ground under my feet (for then do start troubleshooting). I fear Your pin has multiple issues - symptoms interfere - I cannot unbundle the problems - and as some special spice - inconsistency with yesterday ...
Please do the same testings You did "just before writing post-20" ... remove ball - lift playfield - WATCH, question: Is the Rollover-Relay down in the cabinet steady pulling ? Is the 50-Point-Relay down in the cabinet steady pulling ? Greetings Rolf

Hi amymcg
the big difference / question is "is it weekend or not ?".
There is only one way to place a jumper - to place it exactly as shown on a JPG. If there is no room to clip-on the gator-clip where mentioned / drawn ((( the clipped-on gator-clip would also have non-wanted, faulty connection to neighboring solder-lug))) we then must talk and find a way to do "alike test". See the first JPG "marked green jumper, green question-mark" --- we better do not communicate in such form - If I would write "do marked green jumper" - You would have to ask "WHAT exactly shall I jumper ?". See at the bottom of the first JPG the AA, BB, CC, DD - FOUR different ways to set a jumper.
Top-AA, Top-BB, Top-CC are exact implementations --- IF (if,if) it is impossible (not room enough) to clip-on at "Switch-on-Score-Motor-Index-Cam-Position-A-Switch-Solder-Lug-on-blade":

An alternative way to Top-AA is Bottom-AA --- as wire-30-yellow runs in the pin to "Switch-on-Score-Motor-..." and wire-30-yellow also runs in the pin to "Switch-on-Lock-Relay" O.K. - O.K. - we would like to do "Test Top-AA" - as a compromise we do "Test Bottom-AA".
An alternative way to Top-BB is Bottom-BB --- clipping on at solder-lug-wire-73-1-orange-yellow on a better-to-get-at-place.
An alternative way to Top-CC is Bottom-CC --- clipping on at solder-lug-wire-73-1-orange-yellow on a better-to-get-at-place.
See on bottom-right corner of my JPG - "EE" - in a way one or two or more pieces of wire-73-1-orange-yellow do connect many solder-lugs on different relays / switches.

Me and You - we both must know exactly what place to clip-on / have clipped-on - otherwise me or You or we both get confused / led astray - make wrong conclusions.

In Your post-23 You write " ... with the jumper in place ... " - question: Is the jumper set like "My JPG here, Upper-CC" ?

I would like to change strategy - I would like to follow the hint sudsy7 he made in his post-9 --- the Coin-Relay in San Francisco must stay pulling longer then in many other, newer Williams pins.
See my second JPG - some stuff I may want to talk about later - for now look on the bottom-left corner, the Coin-Relay: Wear rubber gloves - toggle-off the pin - then toggle-on the pin - then with an wooden stick activate the armature on Coin-Relay - (simulate coil gets current and pulls) - keep-on pressing the armature , activate, activate - let the motor do his turning - about 2 to 3 turns of 180 degrees - when the huge bank of relays in the bottom of the cabinet (nearby) resets - then let go on the Coin-Relay (no more pressing / activating) - what do the Score-Drums do ? what does the Reset-Relay do ? Greetings Rolf

0San-Francisco-Work-12 (resized).jpg

0San-Francisco-Work-14 (resized).jpg

Hi amymcg
great - You did search (check continuity) on Your own - and found the fault. Greetings Rolf