(Topic ID: 203260)

Bally AS-2518-51 - "Noises" not "tunes" - wrong sound


By cooke

2 years ago



Topic Stats

  • 8 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by cooke
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#1 2 years ago

Hello everyone,
I'm working on a Bally Rolling Stones with a sound issue. The problem is that the board will only emit those annoying fake chime noises and not any of the proper tunes & sounds that everyone knows and loves from the -51 sound board.

Yes, switch 29 and 30 on the MPU are both "on". This board was working fine for a year and then one day it started producing only the chime sounds. Last year, I replaced the pots, caps, sockets and headers. Today I swapped out the rom, 6810, PIA, processor and sound generator. I've reflowed the solder on the headers for good measure. I tested the board in another game and the problem persists.

Pressing the test switch on the -51 produces the "tune" I would expect, so it leads me to believe that the board is just not understanding that switches 29 and 30 on the MPU are on. What part of the sound board determines what type of sounds to produce?

Your help would be greatly appreciated. Thanks in advance.

#2 2 years ago

Sounds vs chimes is often a self-test setting in the MPU.

Lets look at manual...

#3 2 years ago

It is entirely possible for the crappy DIP switches on the MPU to fail open, due to dirt or bad solders. You should check that S29 and S30 are actually shorting the two sides of the switch using a multimeter.

#4 2 years ago

Yeah, so this title only uses the DIP switches for the sound select.

If the game is playing the WRONG sounds instead of just 'some' sounds... I'd look at the MPU and the dip switches themselves.

#5 1 year ago

Thanks for your replies. But, yes, this sound board relies only on dip sw29 and 30 for sound settings. There are no software settings for games with the -51.

Also, I did ensure that the dips are doing their job. Used the meter to make sure. Also, note that I tried the board in a different and fully working machine with the same results.

I am absolutely positive the issue is on the sound board itself.

Still looking for advice. Further help is appreciated. Thanks.

Corey

#6 1 year ago

Since the issue follows the board to another game you can assume it is a board problem.
It would be nice to put that other games sound card in this game and see if it works as a double check.
Sound is generated by the MPU via solenoid addressing from J4 pins 1,2,3,4 and go to the sound board on J1 pins 1,2,3,4.
Those lines go through hex inverter U5 on the sound board and then to U1 on the sound board.
Check the Sol. Address lines on the sound card (J1 -1,2,3,4) and then on the input pins of U1. They should be opposite (inverted) and
changing as sounds are generated.
A logic probe and schematic comes in very handy here. Since pushing the test button on the sound
card produces the proper sounds it is likely either the connector pins on J1 or bad U5 or U1 on the sound card.

#7 1 year ago

+1 what TheWiz said, and in addition there's also a 5th sound select signal called sound address E on the schematics (MPU connector J1 pin 7 to sound board connector J1 pin 12). Sometimes the uppermost bit in the sound select signals is used as a sound bank select.

1 week later
#8 1 year ago
Quoted from TheWiz:

Since the issue follows the board to another game you can assume it is a board problem.
It would be nice to put that other games sound card in this game and see if it works as a double check.
Sound is generated by the MPU via solenoid addressing from J4 pins 1,2,3,4 and go to the sound board on J1 pins 1,2,3,4.
Those lines go through hex inverter U5 on the sound board and then to U1 on the sound board.
Check the Sol. Address lines on the sound card (J1 -1,2,3,4) and then on the input pins of U1. They should be opposite (inverted) and
changing as sounds are generated.
A logic probe and schematic comes in very handy here. Since pushing the test button on the sound
card produces the proper sounds it is likely either the connector pins on J1 or bad U5 or U1 on the sound card.

Thanks to thewiz for pointing me in the right direction. Replaced the 4049 at U5 and all is now well. Precisely the kind of advice I was looking for.

Corey

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