I need some help from you EM experts.

I picked up a Zaccaria Combat from a local woman who had it in her basement since the late 90s. Her children are grown so I don't think it had been played for at least 10-15 years. I didn't turn it on in the basement after reading through some posts about all the necessary checks before turning it on. I was comfortable with what I saw and the price so I bought it because I've been wanting to dip into the EM world.

The only big issue when I got it home was a burnt coil on the match stepper which I replaced. The player 1 100k reel clears to 1 but not to zero when resetting but I think I have a handle on that.

At this point I've gotten more comfortable with evaluating the pin and reading the schematics (see below).

My problem is the typical constant spinning score motor. I have checked all the score real switches, steppers and stepper switches at this point but don't see any obvious points of contact.

Heres what I see that happens

Turn on the machine:
Game over Trip relay turns on
No ball light (expected)
No number of players or player up light on (expected)
Game over light on
Match number light on
If the bonus stepper is manually moved then it resets to base bonus when machine is turned on
GI lights including blinking pops are on
Backboard lights on including score real lights

Push Start button (pulsante in schematics, italian for button) :
Lock relay on
reset relay on
Coin relay beats on for less than a second then off
Game over latch turns on
Replay relay beats on for a second then off
Coin stepper will reset to zero if manually moved prior
ball count stepper will reset to zero if manually moved prior
Player count light sometimes gets stuck at 2 but most recently this has started to go to one after cleaning the stepper

At this point the score motor turns continuously and the score reset relays in the backbox chatter repetatively
Also if I manually unlock the reset relay then the machine switches to the outhole relay chattering and I can play a ball manually with flippers and slings. The outhole doesn't fire however

Thoughts? I'll be back to work on it later tonight. thanks everyone. going through this has been super fun.

Schematic here:
https://www.ipdb.org/files/3609/Zaccaria_1977_Combat_Schematic_Diagram_continuous.pdf

Couple more things. There are some jumpers off the score motor that were there when I bought it.

They go from :
Score motor 4D yellow to 4C Br-R (Pulses 3rd Player No Match unit to Pulses advance bonus)
Outhole relay G-B (schematic E25) to Score Motor 4B Bl-Y (the relay switch is from adv hole score 9th position G+S/G-B --->jumper-->score motor Bl-Y--->ball release coil)
Score motor 1st Imp B yellow to Bonus Relay R-B (E14 on schem). This appears to essentially jump the Imp B switch

Also when the start button is pushed the replay counter does not decrease (I've manually been adding credits for now but will convert to freeplay)

Ok. I knew that was a common cause and figured so based on the schematics so I did check those before posting. I'll look again though since that still makes the most sense. I also haven't looked closely at the bonus resets so I'll look at those too.

On Combat its Index C that precedes the drum unit series, yours must be from the Circus

So I looked again and it still appears that every zero switch with the Br-R-W color scheme appear open. It took me a bit to figure out the 21st switch is the bonus unit switch.

Is there another way to check for a connection (short?) in the zero reset system?

Nothing else would hold the reset relay on? Should I look at every connection that uses the reset relay?

I did try the blocking the reset relay hold switch (saw that in a older combat post) and that does stop the motor spinning. I can't do anything after that to play the game presumably because something downstream doesn't trigger to allow gameplay

Coin and replay relay beats quick then Lock, Reset, and Game over latch trigger on. Coin switch and 1st coin sw add don't do anything.

MarkG 's suggestion was the major help with the solution (I think, just a quick morning analysis so far).

Index C Br-R-W to Yellow of the make-break switch is open when the score motor/index cam is at its start position and the leaf contact is in the cam knotch (?).

I put the meter on it in this position and had a closed circuit.

I then unhooked the jones plugs to the backbox and still (!!) had a closed circuit. That made me think that the only switch left in schematic with that wire color is the bonus stepper which never travels through the backbox. It's jones plug/wire goes separately from the cabinet to the playfield. Indeed the bonus reset stepper looked closed, which is weird cause I had previously checked it. I rotated it through a cycle, adjusted it slightly and cleaned it again. Voila the game worked but... when the ball drains and the bonus scores it starts clicking along again. My bonus stepper must have a hangup somewhere.

Also the ball kickout keeps firing so I gotta sort out if thats a switch issue or has to do with the weird jumper wire noted above.

so close!!

Thanks everyone. I have to work on it later as French toast and the French Grand Prix are the morning plan

Update.

Fixed the kickout, the switch deepest from the playfield had a bent dampener which prevented it from closing after the ball kicked out.

Unfortunately the first problem still isn't resolved. What I thought was the bonus stepper with the 17th switch noted above is in fact on the hole score drum unit. (on the playfield this is the light that advances up the L orbit).

I think my problem is as follows:
If I manually move the hole drum unit until it sits at zero with switches open then the score motor stops, the game is playable. If i drain with the hole score advanced past zero the hole drum unit has difficulty returning to zero and the score motor continues to run. Sometimes a shake will get it to move another space but it still doesn't return to zero.

Looking at the system it appears the coil is never activated long enough (powerfully enough?) with the score motor turning to get the drum to turn?

The hole score drum moves fine when moved by the advance hole score relay (see pic, row 16) so I think the other line in the schematic with the reset relay and hole switch is the problem.

Screen Shot 2022-07-28 at 9.21.28 PM (resized).png

I've also noticed that when I watch videos of gameplay the hole score goes very quickly back to zero

The bonus reset also does this as well. Mine does not however. As noted above the hole reset never makes it back and the bonus does a very slow methodical tic, tic, tic back to zero. In gameplay videos it resets very quickly (5:07 of vid below)

My very beginner EM mind would tell me that what's happening is that the score motor wheel nub (?) (1st Impulse in combat) is only closing the switch once or twice a revolution whereas it should typically very rapidly fire it 5 times, and then 5 times again if the the hole reset or bonus reset isn't back to zero.

I'm finally able to work on this again so going to have a look again today at the score motor but I hesitate to make too many adjustments based on advice given here consistently about not adjusting switches that don't need it.

I pretty much have everything solved.

These scoring drum units have 2 switches that need to close at the 9th position. The one closest to the coil only closes during 9th position. The second from the coil is closed for 1-9 positions and open at 0. The 3rd and 4th switches from the coil is a make or break switch. Switch 3 is closed in positions 1-9 and open at 0. Switch 4 is open in positions 1-9 and closed at 0. The number 2 switch needs the most tuning and a pretty firm contact to allow the coil to fire consistently.

All I have left is to figure out the bonus, I think the jumper noted above is factoring into the slow, once (maybe twice) a revolution of the score motor countdown of the bonus at the end of a ball. It's working so I may just leave it alone.

Ok, back to more questions for the EM crowd.

I have the scoring motor sorted as noted above but now I'm a bit stuck with a issue that I'm not sure where to look on the schematic. I think they're all related somehow.

1. With credits on the pin I can add player 1 and player 2 by pressing the start button but then I can't add player 3 or 4 even if I have enough credits. If I reach in the coin door though and add credits I can add players 3 and 4.

2. Second problem which might be related to the first is that the game doesn't end at ball 5. This seems to happen no matter if I'm playing a 1 player game, 2, 3 or 4. The pin seems to want to give me 6 balls because it usually (I'm trying to get enough games in to see if this is the pattern) will light the game over at the "6th" ball.

Prior to this the ball count was not working and after some adjustments/cleaning I arrived at this stage and problem.

I'm not entirely sure where to look on the schematic for this and therefore not sure which relays to look at.