Williams High Speed LED mod of matrix lamps lowered sound volume in attract mode

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Williams High Speed LED mod of matrix lamps lowered+lost sound volume in attract mode

I just finished replacing all ~62 matrix controlled lamps from under the playfield plastics on my High Speed. I left all flashers and then GI on the playfield and most GI in the backbox as incandescent #44 (PF GI) and #47 (BB GI) due to color temp and beam throw issues.

As I was swapping out the LEDs in sets from the matrix, I noted that the next time I turned it on the attract mode sounds were lower than before. Replaced another batch of ten, turned it on, and even lower. Swapped a few back to incandescent lamps and the sound came back a bit louder, so it wasn't permanent damage, just a direct correlation to amp draw.

The sounds I'm referring to is both the constant "thumping" back and forth sound, as well as especially the "sweeping" sounds that occur when the lights are controlled to come on in sweeping motions and turn off the same way.

The levels of volume have gone WAY down now after the change. However, coin up and play, everything else is fully normal. Only these two types of attract mode sounds, that seemed to be directly keyed off how many lights were on or off at the time, got much lower. Turning up the volume control just makes it slightly louder while making the actual game too loud (for home use)

So, can I assume there is some sort of analog feedback based upon the amp draw to the matrix that was used as a frequency / volume generator in the audio board? I haven't traced the schematics yet, and I'm not as good about analog as I am digital, and only an enthusiast at that and not a professional, but I was wondering if anyone else has seen this on Williams System 11 games or High Speed in particular when swapping out for LEDs.

If so, is there a way to adjust it, without, obviously, placing a dummy load on the matrix which only adds heat and damage to connectors that I was wanting to avoid with the LED mod to begin with.


Edit: 2 days later, there is absolutely NO attract sound at all when I turn the game on. NOTHING plays in the attract mode. As soon as I start up a game, all the normal sounds work fine, and stepping through things in test mode plays fine, but none of the background sounds are there in attract mode.

I cranked up the volume pot and could just barely hear the thumping of the background sound (but no sweeping sound) during attract, yet the volume level of the actual sounds in the game was ear shattering, so there is nothing wrong with the volume pot at all.

So what blew on the sound board (or CPU board)?
 
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Actually, on that game I would have put LED's in the general illumination to reduce burnt connectors. I would NOT have done the switched illumination in LED's and would have left those incandescent.
 
The basic 5500K-9300K blueish cool white LEDs look like crap for GI IMHO. Hot spots with not much throw and more visible for flicker as well.

However as switched behind inserts, I think they look great. Red under Red and Green under Green really made them rich and true in color.

Likewise White under yellow made it look yellow and not orange, finally matching the target plastic color to the lens insert color on the stop lights. And white under orange made orange look true orange vs. very close to a red that the incandescent did.

The fix for the GI torching was to replace the crappy white plastic with round pin (~1/32" wide) posts and flat pins with better friction lock black plastic square pin (~1/16" wide) posts and trifurcon pins. For home use it should not torch again in the forseable future, until they can finally make decent warm white LEDs with good throw (without having green tinges); plus of course dropping all the backbox from .25A #44's to .15A #47's (and a few well placed LEDs behind blue graphics) since the extra brightness is not needed in the home.
 
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So what blew on the sound board (or CPU board)?

Well, nothing blew!


The attract sound that you refer is not an intentional sound effect being generated by the audio system. That noise, or sound, is actually electrical noise, or hash, generated by all of the high current switching occurring in the lighting circuits. The noise winds up being picked up by the audio circuits.

It's worse in attract mode since attract mode displays a more active light show than game play usually does. By changing out the feature lamps, you've reduced the current draw by a great deal, with switching currents reduced the noise level has dropped.


D
 
I believe there is a miscommunication in terms. I will try to find a MP3/AVI clip somewhere that isolates the sound pattern that used to be there.

To be clear, a few days later, I now get ZERO sound in attract mode now--except for the random speech effects. No sound is accompanying the bouncing lights or sweeping sound of the lights that clearly was not electric 'noise'. I never had annoying static or humm or anything; just a purposeful sound pattern clearly tied to the attract pattern.

I did some reading and schematics looking and it appears that 'background' sound is done on the separate sound board, while speech and other synthesized sound seems to be fed from the CPU to the sound board and back through the CPU for final amplification.

Since I have absolutely no sound in attract mode and only the speech and discrete sounds during play (and in test mode), something died with background sound generation and since that is what the sound board is called it seems like the pre-amp there has died before it's fed back onto the main CPU board for the final output, so perhaps something with -12V feed changed when I switched out the high current lamps to the lower current LEDs that may lead back to a power issue if not a amp issue. At least I know where to start checking more.


Edit: On powering up tonight, I had absolutely no music playing after dropping in the coin or starting the game. All I got was sound effects of target hits and stuff throughout the entire game. Jostled connectors and stuff and nothing happened. Went into test mode, Music test produced nothing. Turned it off and back on, and then music was back both in game play and in test mode; however still completely missing is the background thumping and wiping and seemingly just 'background' when in normal game play; so something still is missing.

I measured the incoming voltage at the J3 connector and on the chips on the sound board, and it was +5.10V there for the 5V line. The -12V line measured -14.05 volts at the connector.
 
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