Gottlieb Hollywood Heat (Gottlieb, 1986) Sound issue

[hotrob]

I have a HollyWood Heat pinball machine. I turn it on and everything works great for a while. about two minutes into the game the sound goes low and starts to cut off and on and suddenly the sound is off. I let it sit for ten minutes and the sound is back again.

Thanks everybody for your help

Rob

 

[sleepy]

I don't know pinball machines, but that sounds like either a bad capacitor or transistor / IC audio chip.

With a bad capacitor or transistor, the sound might crackle as it fades out, and with a bad transistor or IC audio chip you might hear crackle and a quiet humming or buzzing sound from the speakers after the sound dies out.
If you suddenly hear a loud humming or buzzing, turn off the machine IMMEDIATELY to prevent further damage.

You might get lucky and it's only a dirty potentiometer.
That would be the manual volume control if it has one.
If it uses a manual volume control, try opening the coin door and turning it up and down several times to see if the sound pops back in and if it does, then turn the machine off and use a potentiometer cleaner on the control, spraying it to get the cleaner inside of the control can and turning the control back and forth to loosen any dirt, but don't leave the machine on for too long if it isn't the control at fault because you don't want to burn out the whole board and it might burn out if there is a bad capacitor, diode or transistor/IC chip.

Btw, I love that machine.

 

[hotrob]

There is a hum at the speaker when working if the volume is way up. When the sound is working and I hear it starting to get choppy, I stop everything and let the flippers go. The sound gets low but keeps working, i wiggle the volume and it goes up again. The I tilt the machine or hit the flippers and the sound is gone, til I shut it down for a few minutes then on and back to working. I think something is getting hot and shut the sound off, then cools and it works

Where would the capacitor, transistor or IC audio chip be located on the machine?? How can these be tested?

Thank you very much for all of your help
This is an awesome machine

I don't know pinball machines, but that sounds like either a bad capacitor or transistor / IC audio chip.

With a bad capacitor or transistor, the sound might crackle as it fades out, and with a bad transistor or IC audio chip you might hear crackle and a quiet humming or buzzing sound from the speakers after the sound dies out.
If you suddenly hear a loud humming or buzzing, turn off the machine IMMEDIATELY to prevent further damage.

You might get lucky and it's only a dirty potentiometer.
That would be the manual volume control if it has one.
If it uses a manual volume control, try opening the coin door and turning it up and down several times to see if the sound pops back in and if it does, then turn the machine off and use a potentiometer cleaner on the control, spraying it to get the cleaner inside of the control can and turning the control back and forth to loosen any dirt, but don't leave the machine on for too long if it isn't the control at fault because you don't want to burn out the whole board and it might burn out if there is a bad capacitor, diode or transistor/IC chip.

Btw, I love that machine.

 

[sleepy]

It *might* be an electrolytic capacitor on the power supply board, but only if the supply is segmented with a separate section for the sound board. And it *might* be an electrolytic capacitor at or near the power input found on the sound or amp board, depending on circuit design.
Any audio transistor or IC chip would be found on the amplifier board, or on the sound board if that's where the analog pre-amps, buffer amps and output amps are located, depending on the circuit design. And then, the first pre-amp might be part of a digital-to-analog sound chip, again depending on the design of the circuit and the IC chips used.

But...if the sound cuts in and out when you wiggle the manual volume control...or when you turn it up and down...
Volume controls should be tight with very, very little wiggle and normally should have no wiggle at all, but poorly designed potentiometers (used for mechanical volume controls, etc.) are often manufactured with loose mechanical tolerances, but no matter. And old, worn out potentiometers can also lose their tolerance from wear and tear and wiggle, losing the necessary contact between the electrodes and resistor plates inside the pot, no longer usable in the circuit.
That could be where the trouble is.

 

[Itchigo]

Unplug the game first and get some electrical contact cleaner (in a can), attach the straw, and spray it into the shaft of the volume control while turning the volume control back and forth. Wait a few minutes before plugging it back in. If you have a dirty volume control this will help. If you wiggle the control and it affects the volume then the control is either dirty or going bad.