World Cup
Williams, 1978Working on my WMS World Cup. Sound previously worked, but now it doesn't. When I grabbed the pot to turn up the volume, I got an AM radio station through the speakers. I can only hear it when I touch the pot.
Pretty weird, but I still don't have any sounds in game or in test mode.
Jason
I remember a Gilligan's Island episode like that....
'and the momma bear said to the papa bear,,,,,'
Why do I store such things in my brain I'll never know....
But to your problem, should like you amp portion is working fine, but now your not sending audio to it and turning up the pot is just showing how un-shielded wires and audio sections work.
You said "Working on my WMS World Cup. Sound previously worked, but now it doesn't." what were you working on? If it was changing the battery holder, the sound select etches on a WPC era machines tended to run under that area.
The AM radio deal was common on Williams sound boards. Especially when there was a transmitter tower nearby.
I remember a Flash at The Sportsman's Den (which was part of the Riverview Highlands Ski & Golf center in Riverview/Southgate, MI) that played WJR (AM 760; The Great Voice of the Great Lakes) since their transmitter was barely a half mile away. Also affected was a Pac Man cocktail table.Touching the volume control on the Flash or the sound amp heat sink on the Pac Man converted the machines to an AM radio!
Riverview Highlands was a "Mt. Trashmore" ski resort built over a landfill. The ski resort closed in 1995.
Quoted from SchertzPinball:Its the System 3 World Cup.
Ahhh... I had assumed it was the Williams World Cup Soccer that came out in '94.. I see the Pinside engine assumed it was the 1978 version. We were both wrong.
Shopping the game out should not have broken sound. Unless shopping included pulling boards.
System 3, no clue sorry.
Quoted from SchertzPinball:Working on my WMS World Cup. Sound previously worked, but now it doesn't. When I grabbed the pot to turn up the volume, I got an AM radio station through the speakers. I can only hear it when I touch the pot.
Pretty weird, but I still don't have any sounds in game or in test mode.
Jason
How technical do you want to get?
Sound board check for +5v and +12v. If those look good try grounding the signal input connector and see if you get any noise. Past that you need to start determining if the CPU is running, if there is a DAC or amp problem, if the rom or PIA is bad etc.
Quoted from Patofnaud:I remember a Gilligan's Island episode like that....
'and the momma bear said to the papa bear,,,,,'
Why do I store such things in my brain I'll never know....
But to your problem, should like you amp portion is working fine, but now your not sending audio to it and turning up the pot is just showing how un-shielded wires and audio sections work.
You said "Working on my WMS World Cup. Sound previously worked, but now it doesn't." what were you working on? If it was changing the battery holder, the sound select etches on a WPC era machines tended to run under that area.
+Karma for the Gilligan reference!
I can hear a low clicking sound from the speaker when I score a switch. The potentiometer works as the clicking goes away when I turn volume down. I don't have schematics and I'm not familiar with this sound board. If I can hear the AM radio loud and clear is it safe to assume the amplifier is OK?
Jason
Quoted from MrBally:Riverview Highlands was a "Mt. Trashmore" ski resort built over a landfill. The ski resort closed in 1995.
I learned to ski on Mt. Trashmore. It closed in '95? I thought I skied there right around that time. Good times. Bummer it closed.
OK, I'm only getting 9v to the sound board instead of 12v. The power comes straight off the transformer at 9v.
Jason - it's a Feature!
Lockman says congrats on turning a not very affordable Pinball machine into 1930s technology. 
Quoted from SchertzPinball:OK, I'm only getting 9v to the sound board instead of 12v. The power comes straight off the transformer at 9v.
9v is enough to power the 7805. Do you have 5v output?
I did some work and now I have +12, -12, and 5V on the board. Still no sound though. I guess its time to replace the sockets.
Jason
Except the radio was news radio lol
Looking at the sound board schematics for disco fever should pin 1 of the Amp be getting 12v? I'm only getting around 3.
No. Pin one is the input to the amp. It'll be AC audio signals in a working system. Hence the DC blocking cap at C12.
The AMP circuit (IC10) should self bias to the needed voltage.
Quoted from Zitt:Jason - it's a Feature!
Lockman says congrats on turning a not very affordable Pinball machine into 1930s technology.
Hello my baby hello my darling hello my ragtime gal....LOL
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Schertz, TX