(Topic ID: 214423)

Bally Sound - Help for MGC


By aobrien5

1 year ago



Topic Stats

  • 13 posts
  • 6 Pinsiders participating
  • Latest reply 10 months ago by FiatsRUs
  • No one calls this topic a favorite

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#1 1 year ago

Mysteriously lost sound yesterday on my Mystic while trying to get it ready for MGC. I get nothing out of the speaker - no static, nothing. Got a different board, plugged it in, got the power on sound, then nothing after starting a game (wrong game ROM in). No power up sound anymore, either. Then something happened with that board, and now I get power up and test sounds out of it. Afraid to start a game or swap ROMs. Is there a way to drain the caps on here or something to reset the board? All the voltages seem fine, including changing voltages for the "with sound" if I push the test button.

#2 1 year ago

Ok, went through test mode with this new board and that was good, so swapped ROM. Test mode there good so tried a game, and it's working! WTF happened here? Did the board/caps get reset somehow or something?? What's wrong with my original board (which still wouldn't work)?

#3 1 year ago

I had a bally Silverball Mania that would not play any sounds no matter what. Redid almost everything. After I had a problem with the solenoid board I put a replacement rotten dog board in and the sounds worked. Ended up selling the game before I got it all worked out but was told the sound signals went thru the solenoid board wiring then down to the sound card. Maybe you have a bad pin or header

#4 1 year ago

It could be anything man, leon has a rom for it too.
Are the headers, sockets, and caps original?
http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#AS-2518-51_Sound_Board_Troubleshooting

#5 1 year ago
Quoted from Tallon:

I had a bally Silverball Mania that would not play any sounds no matter what. Redid almost everything. After I had a problem with the solenoid board I put a replacement rotten dog board in and the sounds worked. Ended up selling the game before I got it all worked out but was told the sound signals went thru the solenoid board wiring then down to the sound card. Maybe you have a bad pin or header

I will have to pull that and check. Thanks.

Quoted from supermoot:

It could be anything man, leon has a rom for it too.
Are the headers, sockets, and caps original?
http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#AS-2518-51_Sound_Board_Troubleshooting

My board was rebuilt by barakandl. Everything still looks solid. Funny thing is, the board I just got working is 100% original. Hasnt been in a game for 20 years.

#6 1 year ago

Try checking the connector and pins. The board is enabled by the solenoid bank select. If that wire is broken or not making good contact to the board it might not work.

#7 1 year ago

Later games using the -51 sound board have software that waits for the MPU PIA's test or possibly attract mode to hit before they become active.

ie... in gold ball or other later -51 sound games if you push the sound board test button before the MPU fully boots up it makes the sound board lock up until it is power cycled. Silverball mania doesnt act like that tho, you can push the sound diag button as soon as power is applied and it will make test noise.

That being said if you put a late model software into an older game using the -51 sound board, it may appear dead. When testing these boards I usually use SBM software as I am familiar with the sound board decoding pattern and how it should sound.

#8 1 year ago

Is there anyway to "manually reset" the board? The one that stopped working seems to be in that state, but a reboot obviously doesn't help.

Full disclosure, I got the "new" board working by doing something totally boneheaded. I pulled it out of the game and set it on the front of the backbox to test voltages. While putting it back, something touched the ground braid, and the game rebooted. After that the sound started working again, but not for the original board.

#9 1 year ago
Quoted from aobrien5:

Is there anyway to "manually reset" the board? The one that stopped working seems to be in that state, but a reboot obviously doesn't help.
Full disclosure, I got the "new" board working by doing something totally boneheaded. I pulled it out of the game and set it on the front of the backbox to test voltages. While putting it back, something touched the ground braid, and the game rebooted. After that the sound started working again, but not for the original board.

Break the sound board into three sections.

The CPU stuff
The sound input stuff
The sound amplification

For the CPU, diag it like any 6802 computer. You need a clock pulse (External clock cpu p37). High reset (p40, DO NOT FORCE RESET HIGH if low YOU WILL BLOW UP THE 4011 chip). If the eprom /CE is pulsing and the CPU is doing work let the game mpu boot up all the way (or use SBM or other old software). Push the diag button and monitor TP4. When sound is playing TP4 (i think it is VMA) will start pulsing. If that looks good continue

For sound input stuff put the game in sound test and monitor the sound signals coming in the sound, inverting through the 4049, and then to the sound chip. If they all make it to the sound chip keep going. The sound chip can fail and not decode sound patterns properly, so keep that in mind.

For amplification problems introduce noise with your finger on a probe. If you get low, but adjustable volume the preamp is usually the cause. Zero sound and the CPU is running and the sound inputs look good, try the main amp.

The Bally 560-3 repair manual is very good for this board and way more detailed than what i typed out. IF you can follow the Bally 560-3 book, you can fix your board.
http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Pin%20Repair.pdf

around page 77 in that PDF file.

#10 1 year ago
Quoted from barakandl:

Break the sound board into three sections.
The CPU stuff
The sound input stuff
The sound amplification
For the CPU, diag it like any 6802 computer. You need a clock pulse (External clock cpu p37). High reset (p40, DO NOT FORCE RESET HIGH if low YOU WILL BLOW UP THE 4011 chip). If the eprom /CE is pulsing and the CPU is doing work let the game mpu boot up all the way (or use SBM or other old software). Push the diag button and monitor TP4. When sound is playing TP4 (i think it is VMA) will start pulsing. If that looks good continue
For sound input stuff put the game in sound test and monitor the sound signals coming in the sound, inverting through the 4049, and then to the sound chip. If they all make it to the sound chip keep going. The sound chip can fail and not decode sound patterns properly, so keep that in mind.
For amplification problems introduce noise with your finger on a probe. If you get low, but adjustable volume the preamp is usually the cause. Zero sound and the CPU is running and the sound inputs look good, try the main amp.
The Bally 560-3 repair manual is very good for this board and way more detailed than what i typed out. IF you can follow the Bally 560-3 book, you can fix your board.
http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Pin%20Repair.pdf
around page 77 in that PDF file.

You're the man. Thanks.

2 months later
#11 10 months ago

Never overlook the obvious; have you tried a different speaker? They do occasionally fail. I recently purchased a TMNT that had no cabinet sound due to a failed speaker.

#12 10 months ago
Quoted from FiatsRUs:

Never overlook the obvious; have you tried a different speaker? They do occasionally fail. I recently purchased a TMNT that had no cabinet sound due to a failed speaker.

Good idea, but I did test the existing one and it seems fine.

#13 10 months ago
Quoted from aobrien5:

Good idea, but I did test the existing one and it seems fine.

Did you attach the leads to a known good speaker and try it in your Mystic (easily done)? Or, take the speaker out of your Mystic and try it in a pin that is know to have good sound. It takes very little time and is worth a shot if you already haven't done it.

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