Hey all,

Picked up our first game ever (of course selecting the most complicated one), and while we've made a ton of progress (it didn't play when we bought it), we're having two problems that are absolutely perplexing.

Maintenance already done:
Cleaned, repainted, and waxed the entire playfield.
Cleaned (or gently filed) all relays.
Cleaned, lightly sanded, greased all steppers.
Re-soldiered broken or problematic connections.
Checked all wire connections.
Bent any relays without appropriate gaps (when necessary).
Reviewed all N.O. N.C. relays, one by one.

Problem 1: Always seems to be 4 players (even when less than 4 players are lit).
When we start a single player game (hitting start once) it uses B1 as P1, B2 as P2, B3 as P3. Then Game Over.
With a two player game (hitting start twice) it does B1 as P1, B1 for P2, B2 for P3. B3 just stays on P4 twice.
It really is only not a problem on a 4 player game, where it increments balls/players correctly.

Problem 2: Left bonus is crossed with right bonus.
All hits for right bonus always increment left bonus.
Right bonus never lights. Left bonus always lights.
Top bumpers that would swap "adv left bonus" and "adv right bonus" always

All help is appreciated.

Hey, sorry paulace and hjh632 . Yes, superlube. Didn't mean it literally, sorry! I'm new to this and the terminology, but I wouldn't do anything that would make things worse. Made sure to do a ton of research before even touching the thing.

So, the player issue was... a loose bulb in the back box. Solved that.

Apparently, it runs through that bulb and because it was loose it was skipping all over the place. We still have some issues with the unit in the back box skipping around, or not hitting the contacts correctly, but we can fix that.

Bonuses are still a problem. Haven't got to troubleshoot that much since the player issue was larger.

Just kidding. The player issue is better, but not fixed.

We pulled the unit out of the back box and serviced it, but it appears that the reset relay isn't being triggered to cause it to go back to player 1 once ball 1 is finished for all players.

So, if for example we start a player 3 game: P1-B1, P2-B1, P3-B1, P4-B1 + B2 + B3. The reset relay works fine when the

Bonus issue is still perplexing. I got the lights to light, which is nice (they were not previously) but there's a few potential issues. First, the schematic ties the bonus unit into lots of things, so that's fun.

The top slings (if that's what they're called) only light the right "advance right bonus" light. If you hit the other one (advance left bonus) it briefly switches back before immediately returning to right.

Hitting anything advances BOTH bonuses.

My best guess is that it *could* be the top eject relay crossing them? It's the only thing that the right/left advance bonuses have in common (that's obvious at first look). https://www.ipdb.org/files/1072/Williams_1976_Grand_Prix_Manual.pdf p.29

Always a puzzle to solve But still, any advice is appreciated to narrow down the search.