(Topic ID: 242297)

Bally AS-2518-51 Sound Board Strangeness..

By Coyote

3 years ago



Topic Stats

  • 10 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by Robotworkshop
  • Topic is favorited by 1 Pinsider

You

Linked Games

#1 3 years ago

Hey guys -
Need a second opinoin on this, as I lost half of my hair out while trying to debug this board and getting mixed results.

Summary of everything done:
It's from a Bally Nitro Ground Shaker. Issue was reported as the sound 'suddenly dropping out'.
Owner did a cap kit.
Amp is good, as when powered up, you can hear a soft hum, and sot crackle as you adjust volume.
TP4 matches what schematics state - 0VDC w no sound, ~2.5VDC with.
TP6 has between 2.5 and 3.0 VDC, 0 VAC regardless of whether sound is playing or not.
TP5 has 0VDC with one CPU chip (original), and with replacement shows 2.5VDC.
Tried four different LY-3-8910 and replacement chips. (1 8910, 3 YM2149F which is a drop-in on this board, since pin 26 is floating)
U8 (LM3900) was replaced.
C3, C2 replaced. Old C2, C3 and U8 had pin U8p3 floating. Afterwards, I cannot remember if I was getting a high or low reading.
U10 (RAM) reported as bad with a memory tester. Replaced with known good working 6810. No change.
On U1, DA0 - DA7 lines, according to logic probe, are always low.
On U1, lines coming from MPU *do* pulse.
On U3 and U2, R/W line is always high. (Read). Logic probe never reports it going low.
U2 (PIA 6820) was replaced with two known working ones. No change.
U3 (CPU) Address lines do pulse.

What am I missing? With TP6 never having AC voltage on it, it tells me it's the General Instruments / Yamaha chip. But 4 of them giving the same issue? .. Hard to believe. With it's data lines stuck low - that points to the PIA. But that has been replaced and same issue. And even WITH that, the VMA line does alter depending on whether the game is playing music or not.

Next steps are appreciated. I'm.. stumped, and feel like it's an idiot thing I'm missing.

3 weeks later
#2 3 years ago

Did it get solved?

#3 3 years ago

Nope, not yet. (I also haven't been able to poke at it yet, as I've had family in town.) I'll be revisiting it, likely this coming weekend.

1 year later
#4 1 year ago
Quoted from Coyote:

Nope, not yet. (I also haven't been able to poke at it yet, as I've had family in town.) I'll be revisiting it, likely this coming weekend.

Have you ever resolved this issue. I am having very similar issue on my Bally Gold Ball I just can't get background sounds anymore.

#5 1 year ago

I’ve had to fix a few of these sound cards now. First one was in a gold ball. Recently did another in a Grand Slam that I’m rebuilding. There are a couple variations of this card. Main difference are the way the traces are routed on the back. One of those has traces close to the mounting holes. Was frustrating on the Grand Slam since the board was repaired on the bench but would fail after installing. That is when I found the two variations. The version with the traces close to the mounting hole can short on the mounting tabs and either prevent some or all sounds or even damage parts.

On these boards I have had to replace one of the 8910 chips and on another one of the 6810 chips, PIA, and DIP sockets. Also check for tarnished leads on the ROM chip.

#6 1 year ago
Quoted from Lovetoplaypinbal:

Have you ever resolved this issue. I am having very similar issue on my Bally Gold Ball I just can't get background sounds anymore.

AH! Yes!

I forgot I started this thread.

I borrowed a local's sound board, and turned out it was cold solder joint on the header - the best I can figure is that heat (after being turned on for a little while) was causing the connection to fail, and that is what caused it to just stop outputting sound.

Reflowed all the headers, and I hadn't heard back from the guy since then, so I'm assuming it was good.

4 weeks later
#7 1 year ago
Quoted from Robotworkshop:

I’ve had to fix a few of these sound cards .. Recently did another in a Grand Slam that I’m rebuilding.

have you still got the grand slam there? im looking for the u4 rom image if you could possible copy it? doesnt seem to be in mame or online from what ive seen so far

#8 1 year ago
Quoted from wiredoug:

have you still got the grand slam there? im looking for the u4 rom image if you could possible copy it? doesnt seem to be in mame or online from what ive seen so far

It is online. If you download the pinmame ROM set off IMDb.org it is in there as ROM U4.

#9 1 year ago
Quoted from Robotworkshop:

It is online. If you download the pinmame ROM set off IMDb.org it is in there as ROM U4.

on nice ..right in front of me and i missed it .. thanks

#10 1 year ago
Quoted from wiredoug:

on nice ..right in front of me and i missed it .. thanks

We've all done that before! Everyone pitches in to help though.

Promoted items from the Pinside Marketplace
From: $ 10.00
Electronics
Third Coast Pinball
$ 12.00
Electronics
Yorktown Arcade Supply
From: $ 10.00
Cabinet Parts
Wire-Bot
From: $ 150.00
From: $ 2.99
$ 59.99
Cabinet - Shooter Rods
Pinball Shark
From: $ 170.00
$ 49.99
Cabinet - Shooter Rods
Pinball Shark
$ 18.95
Eproms
Pinballrom

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, become a Pinside+ member!