Hey folks. I'm having solenoid issues with my Simpsons DE.

Purchased it a couple weeks ago and it worked fine at the fellow's house. Got it home and unfortunately my stairs were too narrow to take the machine up whole, so after putting it off a couple weeks I had to remove the back box. All the plugs are keyed so it was a breeze taking it apart and back together. But now the solenoids are all wacky.

Attempting to start a game the shooterlane won't fire. When you drain, the lazer kick goes instead of the outhole. The L/R goes crazy clicking sometimes. And the center drop solenoid is locked on and fires every time the L/R shifts... which is also every time the lazer kick goes. Which is repeatedly since the ball never leaves the outhole.

After browsing the forums, I pulled the PPB and reflowed all the edge connectors and the L/R. They needed it.
Pulled the CPU board to check if anything fell behind and was shorting... nada.
The solenoids all work when I ground the transistor tabs, and the correct ones fire according to the manual. (Though if I shift the L/R the center drop sol is still locked on.)
Tracing back the misfiring solenoids to the 7408 chips, they all go to different ones. I'm finding it hard to believe that multiple chips have gone bad from a trip up a single flight of stairs.

There's got to be something simple here I'm missing. Or at least a single probable cause. I'm leaning toward perhaps a switch matrix issue... such as an incorrectly installed plug... but I have checked those several times. But who knows, I still could have missed one. Sometimes it's the simplest things that get overlooked by me overthinking it and some fresh opinion helps shake it out.

Any help would be appreciated.
Thanks!
Josh

Thanks folks. The more I thought about it today at work, the more I'm thinking switch matrix as well.... I'll check those specific connectors when I get home. I have the manual and the laserkick and outhole are one row off from each other. Maybe I shifted a plug. I will verify wire colors to boot. I fully felt it was a swapped connector too, but somehow got it stuck in my head that it was the output side. And learning that L/R relay function was new to me. I'm not used to games this new. :/

Ran the switch test it was ok. Solenoid test comes back bad. Lots of solenoids doing the wrong thing. Some doing multiple solenoids. Yet they do the right thing when I ground their driver transistors. Looking like it's on the board.

Alright. I was frustrated with this so I went and worked other pins for a while. But I decided to look at it this week.

So I have no idea how I missed it. But in tracing wire colors to look for any shorts I found it. CPU solenoid connector CN12 and PPB connector J2 are keyed alike AND directly opposing each other, simply different sides of the loom. I must have twisted the loom when I reinstalled it. I'm not sure how my brain determined that when grounding the transistors the solenoids were doing the RIGHT thing, but they obviously were not. I'll just pretend it was late and I was tired and cranky. I guess a fresh outlook is a good troubleshooting tool. And I just refused to believe that something would have gone that wrong with the board moving it up a flight of steps.

On a side note, any idea why the flippers would be ridiculously strong? It has the (as far as I can tell) proper 090-5020-30 coils. Both measure 4.1 ohms. And although the wire looks not smoothly wrapped, it doesn't look like they were rewound / wrappings removed. Pictures online look like wonky coil wrapping too. And the original marking tapes are around them yet.

Thanks again for the help.

Josh

Seriously? Damn. I cringe with every shot. Feels like I'm going to break things. And my middle pin drop IS broken. Any way to calm them down? Inline resistor? Different coil? Or should I just leave it be... since it's how it "should" be. I'm torn. :/