(Topic ID: 321183)

NVRAM WEEBLY AS-2518-50 sound board issue

By Arcane

1 year ago


Topic Heartbeat

Topic Stats

  • 15 posts
  • 8 Pinsiders participating
  • Latest reply 1 year ago by jj44114
  • Topic is favorited by 1 Pinsider

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#1 1 year ago

I bought an NVRAM WEEBLY sound board for my Bally Playboy, about two years ago. The board has been working fine for a few months and I did not use the machine for the past 6 months. Now, when turning it ON, everything works but the sound board generates a lot of background noises, like a rumbling. The sounds and various Playboy chimes and melodies are still audible, but the background noise is really obnoxious.

Everything else works perfectly on the pinball.

I was wondering if people have been having issues with these sound boards or if I am just the unlucky one. What would be another alternative to replace the Bally Playboy sound board, short of finding a true Bally sound board for that machine?

Thank you for your help.
Yves

#2 1 year ago

barakandl is good peeps. I'm sure he will assist you.

#3 1 year ago

He is the best. Contact him.

#4 1 year ago

Check connector

#5 1 year ago

This board has a logic ground return and a 43v to 12v regulator return. When the two grounds are at different levels it lets out a nasty hum. Ultimately this is a likely connector issue at the 20pin rectifier, top right SDB connector, sound board connector, or the ground braid between the cabinet and head is not connected.

The easy fix is usually to unscrew the sound board from the grounded backbox mount and let it float up off the grounded screw down points. The proper fix is likely repin the ground connector with resistance.

#6 1 year ago

Thank you Barakandl, I will look into these grounds. What you are describing is definitely close to what I am hearing.

Thanks
Yves

1 week later
#7 1 year ago

No luck so far.....

The Sound board is insulated from the metal shielding on the backbox. I tried using one of the mounting holes linked to the ground, and the humming became even worse. So back to all four insulated posts, like it was when it was working.

Could you specify which pins of the sound board connector should be linked to the ground? Thank you in advance.

Everything else on the machine is working perfectly.

Yves

#8 1 year ago
Quoted from Arcane:

No luck so far.....
The Sound board is insulated from the metal shielding on the backbox. I tried using one of the mounting holes linked to the ground, and the humming became even worse. So back to all four insulated posts, like it was when it was working.
Could you specify which pins of the sound board connector should be linked to the ground? Thank you in advance.
Everything else on the machine is working perfectly.
Yves

I don't know the pinout right off the bat (though manual/schematics are available on IPDB for all of these Bally classics.)

With these Bally classics, it's best practice to fully repin the top right SDB connector, and I'd probably go ahead and fully repin the sound board connector as well. The original connectors are 40+ years old on all of these games, and weren't meant to last this long.

8 months later
#9 1 year ago

I was able to locate an original BALLY Soundboard from Big Daddy Enterprises and mounted it in the backbox.
Sound was back with no humming and unpleasant noises. The original sound board sounds a little bit different from the NVRAM, but works very well and is perfectly silent.

DSC06676 (resized).JPGDSC06676 (resized).JPG

You can see the new old board in situation, above the fan and next to the transformer.

Yves

#10 1 year ago

I have never seen that voltage regulator board before. I wonder if switch mode noise is getting into the 43v - 12v regulator circuit. Do you have a stock SDB or different SDB to try? I will say an EZSBC on a stock bally driver board absolutely can introduce switcher noise into some Bally sound boards (cheap squeaker i think it was).

This sound board is one of my most popular boards. There are ton of them in service over the last 5-6 years, there is not a general design issue with them that should make them hum. If anything the grounding and filtering should be better. They are dead silent in my games (assuming the connectors are good otherwise nasty ground hum with bad connectors).

I can check, repair/replace the sound board if you want to send it back to me.

#11 1 year ago
Quoted from barakandl:

I have never seen that voltage regulator board before.

That's @Arcane's own design:

https://pinside.com/pinball/forum/topic/oh-no-another-bally-classic-solenoid-and-regulator-board

#12 1 year ago
Quoted from Arcane:

Sound was back with no humming and unpleasant noises. The original sound board sounds a little bit different from the NVRAM, but works very well and is perfectly silent.

Thanks for the post Yves. We sold five to six -32 or -50 boards in a short amount of time, and we test every one in an actual game.

https://www.bigdaddy-enterprises.com/ProductPages/usedballyboards.html

Todd
Big Daddy Enterprises

#13 1 year ago
Quoted from barakandl:

This sound board is one of my most popular boards. There are ton of them in service over the last 5-6 years, there is not a general design issue with them that should make them hum. If anything the grounding and filtering should be better. They are dead silent in my games (assuming the connectors are good otherwise nasty ground hum with bad connectors).
I can check, repair/replace the sound board if you want to send it back to me.

That NVRAM sound board worked well for 15 months. Then it started developing the humming noise. I tried checking the grounds but nothing did it.
I am happy to have an original BALLY sound board in my machine now, and will keep the NVRAM board for a future project. It may work better in a different environment.

Yves

#14 1 year ago

The board you have is not an original board.

#15 1 year ago

To clarify, the SDB. I’m guessing that’s part of the problem

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