Did you try wiggling the socketed IC's ont the S&T and rebooting?Ive fixed a few of these sound boards that just had corroded or sloppy sockets also check the main larger connector if one of the pins are not making contact it will stop half way through diognostic startup most likley a crap socket and this S&T would be missing the voice IC becouse there is sound only on this board.
Ifyou have several targets dead see which switch matrix wires they have in common if its the same wire most likley a bad pin on the sw matrix connector or diode on the mpu also check the connector ont the opticle board might have poor connector or cracked solder joint

Sorry for the resurrection, just wondering if this was ever fixed? I'm having the same issue with Bally Rapid Fire, I get 3rd flash but no 4th (5th not required for Rapid Fire). I've replaced all caps except the 2uf and the 4700uf caps, didn't have them on hand. I've replaced the 6821 at U11 with a known working chip, and gave it a new SIP socket. I re-flowed the solder on the connector pins and they look in great shape. I get static when I adjust the sound pot up and down so at least I know the speaker's working. I even tried swapping in a new Ultimate MPU to rule out the MPU but it didn't help.

Should I replace all the sockets that have chips? It doesn't seem necessary when I get to the 3rd flash and I don't like tempting ruining the board with unnecessary soldering. Should I order in the last 3 caps to be sure they're not the problem? Any insight is much appreciated.

Just one more flash and I'm there! Would be great to have sound... Thanks.

PS FWIW I had a target that wasn't registering, like the original poster. I took the opto board out and reflowed the solder on the connector and it was all good.

I saw someone post about a similar problem and it really helped me out. It made me realize that my jumpers were backwards for the sound pots and that the previous owner had them set to bypass the sound and speech pots on the board. I needed the pots to be working, and what I read about them on the schematics was confusing enough that I thought they were in the right way. I assume the previous owner replaced the sound board but didn't know to change the jumpers.

I changed them from "M" to "N", and "CC" to "DD" and I have sound, and working pots! Cheers.

Oh, and for Rapid Fire, only 3 flashes happen on the Squalk n Talk board.

Wow, you own a Rapid Fire!!! And it almost works?? Amazing.
One of my last projects at Bally. Had a sample in the employee lunchroom and I could never get it to work more than a few hours. Most of these were dumped into landfills or converted into other games like Centaur or EBD limited. Post a video of this game running if you can.

Hey BigAl, Yes it works amazingly well. It had some issues with the balls jamming up at first, but I've gone through all the workings and cleared everything up... works great now! I haven't had a problem with it since then and I'm hoping it'll stay this way for a while. I did make a video on YouTube of me playing poorly but the game plays perfectly. It takes time to learn all the strategies and timing, and I'm still not there but I'm getting better. I've had it over 1 million many times but have yet to reach the elusive 2 million mark. I think if I made it that far I'd be exhausted, but it would feel like I really accomplished something!

It's cool to hear from someone who actually built these things. Cheers!

Hi. How did you fix you ball jam problem?

There were parts of the troughs that they roll through that needed to be cleaned and adjusted. Also there were optical swithches that needed cleaning and touched up solder on their connector pins. If they can't read the balls coming through, the whole process quits. There was a fair bit of going through it to find all these issues, it just meant running it and observing everything that happened in the process.