Just brought home a nice Medusa and everything is great except it is currently only a box of lights. Game worked great when I bought it, but it did not survive the ride home.

I turn it on and it starts up just fine. Lights come on, displays show up nicely, drop targets do their dance, has 18 credits (and I can add more), the ball is in the game, and the MPU LED flashes the right number of times.

Eagerly tap the button to start a game and....... nothing.

It's my first early SS Bally and so I look up how to get to the service menu (or Self Test) and hit that button.... Nothing happens.

I've tried all the obvious stuff except re-soldering connections. (checked for loose wires, checked fuses, reseated all the connectors on the boards, it has a remote battery and no acid damage, etc.)

Oddities:
I used to be able to make the game tilt, but that no longer works from any of the tilt mechanisms.

The solenoid on the coindoor was warm and noisy, so I clipped the wires to no positive effect.

Having both the self test menu and the game start button out simultaneously seems odd to me and I don't know if there is a correlation.

Suggestions welcome on any additional troubleshooting tips.

Thanks for the quick responses.

The connector is keyed and in the right position. I thought I was going to have to remove the backbox and was surprised when it folded down for transport. Until troubleshooting, I didn't have to remove any of those connectors.

Just so that I'm explaining things correctly. Here is a picture of the coil I clipped on the coin door as it was very warm and making too loud of a high pitched noise. I must admit to not being able to discern its function.

coil (resized).jpg

Yeah, I’ve tried that one a couple of times.

Thanks for the image on the spring. Makes much more sense. It was loose and that was my first guess on where it hooked.

Last of the easy, yet unlikely, stuff I could think of has been tried, but cleaning contacts on the MPU and resoldering the self test button, credit button switch, and out hole switch had no positive effect.

I'm nonplussed why the self test menu, which could potentially help indicate the problem does not function. Any suggestions on a non-destructive way to bypass the switch and rig a way to toggle on the menu at the MPU board?

Is there some extra step to entering this self test menu on a Bally beside just tapping the button the I might be missing?

One thing I have noticed is the Neptune's Cove in the upper left will fire and kick the ball out. I'm guessing it's the one coil that needs to work before the game starts so the ball does not get stuck there. It also indicates that it's more then just the lights and drops that work.

I took some quick shots before running out of my house this morning and so they are not going to win any awards, but here they are. The MPU does do the proper 7 flashes and so I don't know if it's the board, but if you see anything I can act on, I appreciated the help.

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I don't think that is corrosion in the lower right of the board by the Bally logo. I believe it's foam sticker label residue.

While they make me feel like a moron with limited reading comprehension, I do appreciate your visual aids. Thanks again.

I was so fixated on the battery area for no reason, that I completely and inexplicably misread your accurate observation of where I should be looking.

Thanks. I will focus on that area when I have access to the game.

I know all of Pinside has been at the edge of their seats desperate for news of the state of my Medusa... and IT LIVES!!!!

Seventy gazillion internet points to Quench for rolling much higher on his perception check that I did and noticing the corrosion on the J3 MPU pins and taking the time to help an obnoxious stranger.

The game once again plays as nicely as it did when I tested it before purchase.

Thank you all for the help! I can now Challenge Medusa.