Good to know! This info may come in handy for me someday when I get an EBD of my own!

Glad you're feeling better! I've re-read the whole thread at this point and I wish there was something I could do to help. Here's one thing that may be useful in the troubleshooting of this game, the schematic is freely available on the internet pinball database (ipdb.org): http://mirror2.ipdb.org/files/762/Bally_1981_Eight_Ball_Deluxe_Manual.pdf (schematics are toward the end of the manual)

So, just to confirm: with the 8-ball drop target reset coil and the left slingshot coil both disconnected, but all other coils connected, you get the game to boot up and you can start a game? But as soon as you connect either of those 2 coils the fuse blows?

When you had all of these disconnected, were the power wires (orange, right?) still daisy chained together even though they weren't connected to the coils? Or were all wires separated and left hanging?

Oh right, you only cut off the control wire. So if those coils aren't shorted then it's all in the board. That would be Q2, Q4, Q6 and their associated diodes. U1 is the predriver for all three; it could be bad as well.

U1 is all separate circuits internally, it doesn't have to fail 100%. Also, the outputs of decoder U2 for those coils could be locked on.

Check the outputs of U2, pins 1-11 and 13-16 and see if pins 1, 3 and 6 are different from the rest. Mine read about 3.8V. Then check U1, all pins on mine read 1V or less.

According to the schematic available at ipdb.org, pin 12 should be ground. You may want to grab a copy of it just to verify. Here's the link again: http://mirror2.ipdb.org/files/762/Bally_1981_Eight_Ball_Deluxe_Manual.pdf

Good luck! You've gotta be getting close to fixing this thing!

You can use the metal shield or ground braid in the head for ground.

Don't know if you usually socket the chips, but it's definitely worth doing so! Sockets are cheap and make it convenient if one of them goes bad again. Might be worth getting a few extra driver transistors for stock too. Let us know what happens!

I'm confused on your chip readings. Can you report the readings of U2 pins 1-16?

By PS board I hope you mean solenoid driver board, the upper right board in the backbox. That is the only board we are concerned with now.

If that's the case, then the readings for U2 look good and the readings for U1 look suspect. I would replace U1. Hopefully, it's socketed, but if not, add a socket. It's a CA3081 and these are getting hard to find. You may have to buy a good used, tested one.

If you go into self-test and change settings 16 on up to '03' that should enable all of the sound effects. The manual explains how to step through and make changes.

I grew up playing the game so I'm used to the background sound, but I can understand it can be annoying. The tempo increases the longer the ball is in play and then it switches to a completely different sound, which I really like.

^^^^I like the background sounds on those 80's games -- the sounds most people don't like.

I like the back ground sounds as well, but if you don't have a battery or memory cap on the MPU, the settings will go back to 00 by default. This is for settings 16,17,18 and 19 coindoor adjustments. You also lose the HSTD without battery backup.

Yes all your settings should now be kept in memory.

They don't actually get programmed to '00' by default when the battery dies. They don't get set at all by the game code -- so they can be any random value after the battery has failed.

Although it would have been nice, Bally didn't include a routine to test for a dead battery, and didn't really have enough backup RAM to do it anyway.

While it would be technically possible to read a value from backup RAM, and if that value was not what you expected, assume the battery died and set all the game settings to a default value, there's not enough free space on the 5101 to do it. If you didn't care about the audits, you could overwrite those and do it--but then I guess you'd have to find the code that writes the audits, and take that out, so it wouldn't interfere with your battery test code....

Here's one more thing you could try. Does the fuse ever blow with the coin door open? I would give it a try. I had a Firepower II that was blowing a fuse because of coin door wiring shorting to ground due to vibration. You might be running into similar issue.

Also, have you disconnected the coin door lockout coils? They look like a little pancake shaped coil. You don't really need that coil in the game for home use. It's not really even needed for on route either.

The switch blades need to be adjusted. If the contacts are too close, vibration from the other pops will set it off, it's a common issue when there's cluster of pops like this. There should be about a 16th of an inch gap between the contacts.

Whoa!!! After all this time, it is *done*!!!! Congratulations, Blake! I knew you guys were getting closer and closer to getting it all fixed up, and it's so great to see you've succeeded! Huge props to Lovef2k and dothedoo for their persistence and consistence! And huge props to you, Blake, for following up on every suggestion and putting in the many hours of repairing, reporting, and not giving up! This was a highly educational thread for me, and I'm sure for others too. This also stands as a shining example of what a great community we have here. This makes my day!

I look forward to seeing future progress on the game! (and since reading this thread I've decided that I need to get myself an EBD one day...)

Enjoy your fully-working game!

Good deal! Glad it's working.

Sorry I have been busy lately and not following up. It feels good to bring these games back from the dead. When I bought my first game in 2008, I didn't know how big the hobby was and how many great people and forums were available until I started working on that first game. I'm sure this EBD will be the first of many games you will buy