The machine has been working fine forever, but recently it has developed an issue where the speech activation phase works fine, the head rotates to the optics, you knock one ball in either eye, it holds it and gives you a second ball...all normal, but when you hit the second ball in the other eye, instead of the game saying “you look good,” spitting the balls out, and rotating to the next phase, it spits the balls out, the head does not rotate, and the music stops.

Sometimes it will take 3-4 cycles of activating the optics before it finally acts like it should and proceed to the next phase. Other times after the optics are activated, the music stops, and the head does not rotate, the game will do a ball search even though the ball is in play and hitting targets. I’ve reseated all connectors on the boards, reseated the roms and even the PLCC controller on the MPU. The head cycle test works fine and homes the head normally. The head always returns to the speech face after the game is over like normal.

Any ideas? Thanks.

I should add that the face turns left during game play and right in the test menu. So it’s turning both ways but still gets stuck on the optics face during game play. If you activate the optics 5 times, on the 6th time the face will turn. This is consistent. It takes 5-6 times of activating the optics before the head eventually turns to phase 3. So the system is working but why does it take 5-6 times? I’m even more stumped.

Are you referring to the program/revision rom? No, not yet but it’s on my list. Going to verify the checksum first and see if it’s corrupt.

Thanks guys. Tournament mode disabled and full factory restore accomplished. No change. The Prom checksum is good but it looks like I’ll have to burn a new one be just to rule it out. I did however find out that if you hit the left eye first, then the right, the head will rotate as advertised on the second attempt. The first one still fails to move and the music cuts out. If the right eye gets hit first, then it takes 5-6 cycles of hitting the balls in the eyes before the head rotates like before. The eye and head switches are all registering perfectly and I can move the head left and right in the menu, and it always goes back to the mouth on power up and when a new game starts, so that means the relay and everything is good. It’s got to be the program rom. If it’s not, I’m at a total loss.

Well, it’s officially fixed. Here’s the scoop. First, I want to thank everyone for their suggestions and help. I removed the MPU to replace the PROM and reseat everything one more time. After reinstalling it, the problem went away and everything is working consistently as advertised.

I had already reseated everything once before and the problem remained, so I knew that wasn’t what fixed it. I reinstalled the original PROM as well and it’s still working, so replacing that wasn’t the solution. All I was left with were the switch connections. If I positioned the J207 connection just right, everything worked. If I moved it around a bit, the problem came back.

So I removed the MPU again and reflowed all the header pins on all the switch connections and everything is working perfectly now. After all this head scratching, it ended up being a bad connection on J207 at the MPU. In hindsight, I should have taken note of which pin it was so I could trace it back and see exactly which switch/row was affected, but I didn’t think of it.

Anyway, thanks again and it feels good to get this tackled. See you guys on the next adventure.