I've got some experience with EM's but I have an issue with a Gottlieb Big Brave that has me stumped.

The game was resetting but the Player one score reels were really sluggish getting over the nines. So I cleaned and adjusted them. I got the 10's, 100's and 1000's all working but was having trouble tweaking the 10,000's. When attempting to check progress of the last 10,000 adjustment, it went haywire. Now all Player 1 score reels each advance just 1 digit, then player unit steps up and and resets all player 2 score reels correctly. Game will then kick out ball 1 ready to play.

On a probably related note the "L" relay (1000 points) causes the player unit to step up to player 2.

Before posting I searched for a similar problem and found this post for a Big Shot that describes almost the exact problem, but was never resolved.

https://rec.games.pinball.narkive.com/6AWGSWgR/em-tech-gottlieb-hot-shot-game-starts-before-player-1-score-reels-are-zeroed-help

Thanks Howard, It was P3E. It needed a lot of adjustment to get enough throw to stay open, which was strange because it worked fine earlier. I had hoped that the problems were related but the L relay still causes the player unit to step up to Player 2

If I score 1000 on the playfield or trip the L relay by hand, it steps up to Player 2. It will then hold and score correctly on Player 2 until the ball drains and resets to Player 1. Then as soon as 1000 is scored it steps up to Player 2 again.

I've looked over the schematic and I can't find any connection between the L relay and the Player unit.
All switches on the L relay appear to open and close as they should.

OK tried the suggestions. Inspected all Player 1 score reels. All open and close as they should. I can't see any blades or wires touching that shouldn't be touching. I even put paper between the switches. Still jumps to 2nd player with a new twist:

Start game with all score reels set to 1's. All score reels reset to zero. Ball kicks out, Player 1 active.

At this point I can hit the 100 point target as often as I want and it scores as it should, at the 9 it carries over and advances the 1000 unit. But when I hit a 500 target, it scores 5500 as if the 9th position switch is closed (it isn't). It won't do this if the 1000 unit is on zero.

The 10 point switch scores as it should as long as the 100 reel is on zero. If the 100 unit is on any digit other than zero the ten point will carry over and advance the 100. At this point the 100 switch will also advance the 10 until it hits zero.All the while it will occasionally still advance the player unit to player 2. Or score on player one and 2 at the same time. When draining the Player 1 reels will all reset to zero as if starting the game over.

Player 2 works as it should.

Because of the behavior of the reels seeming to want to get back to zero. I'm thinking it is still trying to reset somewhere, but I'm not sure where to look.

Yes, That's exactly what I did. It exhibits all of the symptoms listed above. With both 10,000 units set to one, i can hit the 100 point relay 9 times without it advancing to player 2 on the tenth hit when the 1000 changes back to zero and the 10,000 advances to 2. It steps up to the 2nd Player.

It will score alright, (just hitting the 100 point target) but when the ball drains the 1st player will reset to zero as if I restarted the game, but it still steps to Ball 2 (or player 2, if in a 2 player game). It will play all the way through like this and when ball 5 drains it will go to "Game Over"

When it steps up to 2nd player, all scoring works fine and a drain adds bonus and steps back to player one as it should. Then, when back on Player 1 craziness continues.

I'm thinking that because the numbers only advance together when they aren't on zero and the fact that it resets to zero on a drain, that it may be finding a second path to the score reels via the reset relay. I'm going to inspect the reset relays in the control bank and see if I can find any issues. Anywhere else I should look?

Machine worked when I acquired it about a year ago. I had some other machines to work on and just got to this one. First set up, the score reels wouldn't reset due to being gummy. Cleaned and adjusted all of the score reels (both players) as I've done many times. They reset all the way around easily when activated manually. Started game and had the condition first described in original post. Adjusted P3E and everything reset as it should.

Then I began testing scoring switches on playfield and discovered the double reels advancing when not on zero. I was concentrating on trying to fix that and the step up to Player 2, when I discovered the drain issue. The Player 1 reset on drain may have been there all along.

One thing I noticed is the 100 relay when activated by 100 point switches works every time, Until I activate a 500 point switch which runs through the score motor. After that the 100 point relay will move the 1000 and the 10 until they get to zero.

I removed the bottom board so I can get a better look at the control bank and score motor switches, That may take a few days. If I can't find anything I may shoot a video and see if that might help.

OK. I've got the double score reel and stepping to player 2 and resetting on drain, cleared up. Turned out to be P3 switch stack. I may have over adjusted when I was working on it earlier, or I might not have gotten that plastic lever that goes on the bottom of the stack lined up right. Once I took it apart readjusted all the switches and reassembled, all those weird issues disappeared.

New problem is the 10,000 point score reel will not reset to zero. I though no big deal, "score reel switch needs adjusted". I've adjusted my share of score reel switches (including some of the finicky Gotttlieb switches) and this is not a switch issue. I cleaned adjusted, readjusted, opened and closed the switches with my finger while machine was resetting, blocked them with paper and jumpered them together. Still goes right past zero and continues.

This is the Gottlieb series where the zero switch closes at the zero position, so I thought jumpering the switch closed would create a zero condition but it doesn't.

If it's not the score reel switch does anyone have any idea what might cause this?

I blocked the runout switch with paper. It does stop advancing since the path to the score reel is permanently open. At this point the score motor continues to turn as if the reset hasn't completed, even though the score reels have all stopped advancing.

This continues to happen regardless of the state of the reset switch. I can leave it alone, block it with paper or jumper it. With the paper in the runout and a jumper on the reset switch it should think it's at zero and complete the reset.

I can achieve the same effect by blocking P3D instead of the runout switch. 10,000 score reel will stop turning but Player unit won't advance the one more step that it needs to complete the reset. Like it would do if the score reels weren't reset.

If I advance the player unit manually one time or close P3E it will begin resetting of the 2nd player, complete the reset, and the game will start.

I'm going to try jumpering all the 1st player reset switches closed just in case there's an open at one of those. I think they are alright but you never know and I can't think of any other reason why it won't complete the sequence.

Thanks for you help DaMoib. Anything else I might try?

Thanks for all your help DaMoib, Reset problem is fixed. After jumpering all the score reels everything reset so I went back over all the score reels switches with a magnifying glass and sure enough, a switch on the 100 reel wasn't closing.

Oddly enough when I had the player unit issue everything reset and I had only messed with the 10000 reel, so I was convinced that was the problem. Evidently the shorted switches in P3 stack were also letting the score reel reset with an open switch.

Now I have a new problem, Not new, I noticed it earlier but thought it would be an easy fix. I get no Bonus advance from the D relay (500 points + 1 advance). The A relay (100 points+ 1 advance) works fine. The D relay gives the 500 points but no advance. Thought it was just an open or dirty switch on the D relay, but after cleaning and jumpering it, it still doesn't work.

The rest of the path is through several score motor switches. I tried jumpers on each one (one at a time) and it will pulse the advance but it does so 2 to 5 times.

See attached for where I tried various jumpers.

bbsc (resized).jpg

I'll give your suggestions a try tomorrow.

If it's not too much trouble, can I get someone to post a photo of a Big Brave Motor Switch Position card that is usually stapled to the inside of the cabinet. Mine is missing. You don't realize how useful they are until you try working without one. Thanks

Unfortunately Pinball Rebel doesn't have these. The card I need is a game specific Score Motor Switch Position card. It should never be removed from the machine, but sometimes they are missing. I usually take a picture of mine in case I need to look at it outside of the cabinet. Here's one from my Spin-A-Card:
sacmotorscan (resized).jpg