I am having many sounds problems with my Bally Skateball where sounds are either missing or wrong. When I start again it makes what I believe is the “Slam” sound (sort or like an ambulance siren cadence) which continues until the ball is launched and hits a switch or target. The switches seem to all work properly but the 1-2-3 lanes make no sound nor do the “special” lanes. When the game finishes it does not play the familiar “game over” tune. Also the collect bonus does mind the winding score up sound when collect bonus is achieved. I have tried two different sound boards but still no resolution. I am thinking it is possibly something in the switch matrix or MPU. I appreciate any ideas on where to look. The game otherwise plays completely fine. Thanks. Mike

Brenna, Thanks for your reply. I have repinned all of the connectors in the entire game and the mpu was redone a few years ago. I assume it is still possible that there is residual damage that is causing the problem though. I’m mostly curious if the problem resides In the MPU or header pins or if I should look at the possibility of a switch diode causing problems....This problem has confounded me for some time...

Just a thought... this is my second Skateball game. I sold the other one. I sent the mpu and sound boards out to be rebuilt. Is it possible that the jumper settings are incorrect? Here is a picture of the sound board.

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Thanks for the replies. Ok, so I looked into a couple of things. Been a long time since I looked into this and had forgotten where I left off. I have another sound board that I installed as well as another mpu. I gained the scoring sounds but still have problems with the others I mentioned. I tried another new sound chip and there was no change. A couple other things I didn't mention earlier is that it doesn't make the player add noise when you start the game. It also does not seem to provide good volume when the A and B lanes are hit. It seems like there is some static when the 1-2-3 lanes are activated but it can't make the proper sound. I'm really stumped! If it would help I can probably make a video later showing all of the sounds it makes or fails to make.

One more thing...the original.mpu I had in the machine had a chip at U5. The one I put in now has no U5 chip. Both have chips at U10. I think the jumpers are correct.

Update.... I just got another (third) sound board and put the sound rom from the current board and now ALL sounds are working!! I’m very surprised my prior sound board wasn’t working because when I sent them out for rebuild all of the caps were replaced. I’m not sure why both boards were having issues making the same sounds....

I do have a new problem however with this newly installed board. The volume is very low and turning the trim pot all the way up does not do help. I do not suspect the trim pot is the problem as I would expect it to at least momentarily get loud as I turned it if it was dirty....any ideas on where to start?

Thanks, Brenna. I will try and get to that as time permits. My eyesight is not what it used to be so soldering is more challenging then it used to be. In the meantime at least I have sound, albeit at a lower level than I would like. I would like to get the other boards working first before I rebuild this one so I have all of the sounds Working while the machine is used now. I especially want to get working the one that has already been upgraded with new caps and trim pot. Is there anything else I should consider to try and get them working. New chips (other than the sound rom)? All three sound boards seem to be configured the same way with B-C jumpers from the factory.

Thanks, Brenna. I will do that. Incidentally, it's likely that he did the work on my skateball mpu that I just swapped out to use as a spare. I bought mine in Michigan after all. looking at the picture of my MPU I'm guessing the Jerry label is referring to Jerry Clause!

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