Robotron No Sound

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Okanagan, BC, Canada
My cocktail Robotron needed a battery change after sitting for about a year. I turn it on, but no sound. No error codes, no ROM or RAM errors. All tests indicate that the machine is ok. All the parts are original and all the boards are from the same set. As usual, it worked fine last time I played it.
I'll check the connectors and plugs.

Suggestions?
 
Do you have all your voltages? all 3 LED's lit on the power supply?
 
Volume pot connected ? ... and turned- up ?

Speaker wires connected to [working] speaker ?


If you touch the heat sink on the Amp transistor
do you hear a hum ?
(... you should, otherwise you Amp might be bad ... )


Steph
 
Could be lots of things. Just today I was messing with a Williams sound board that had no sound output. found a tiny crack in the top of one of the small chips in the middle (can't recall which). replaced it and sound is back...
 
Check the cables. When you were in messing with the battery, you may have bumped the sound cable or the power cable to the sound card. Those old IDC connectors in the original wiring harness were fast and easy for the harness makers, but they are worthless 20+ years later.

ken
 
Connections look good, (will check though). no sound in test mode, 3 led's are lit.
the cap in the sound boars looks fine, but I'll pull it and have a look and update.
thanks for the suggestions so far.
 
both the fuses are intact and not blown.

There are 4 test points on the Sound Board.

+5V
GND
-12V
+12V

Check to make sure those are all present and close to the correct values. I had an issue with defender where -12V was missing, so no sound. Once that was fixed sound board worked fine.
 
Okay,

I had the same problem on my Joust today. It had been previously working, and then for no reason, just stopped!

Pressed the test switch on the board and nothing!

Played with the sound pot even swapped it out with a known working one and nothing!

I took Dokert's suggestion about the fuses - they looked good, but are they making contact?

I twisted the fuses in their holders, powered on the game, and.....

There was sound again!!

In the end, the fuses that "looked" fine weren't making contact.
 
Okay,

I had the same problem on my Joust today. It had been previously working, and then for no reason, just stopped!

Pressed the test switch on the board and nothing!

Played with the sound pot even swapped it out with a known working one and nothing!

I took Dokert's suggestion about the fuses - they looked good, but are they making contact?

I twisted the fuses in their holders, powered on the game, and.....

There was sound again!!

In the end, the fuses that "looked" fine weren't making contact.

So the "It's just a fuse" holds up in this case (sorta :D)

Glad you got it working.
 
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