Just picked up a Sinistar upright...no sound :(

Robot Ron 2

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I picked up a Sinistar upright from a local collector. I bought it knowing the sound didn't work. I am getting power to the sound board but it is definitely not working. Any recommendations on where to start looking on the board?

Thanks guys!
 
Did the game come with schematics? Have you checked that all the cables are plugged in? Visually inspected the wires to the speaker..and made sure that the speaker isn't broken?
 
Did the game come with schematics? Have you checked that all the cables are plugged in? Visually inspected the wires to the speaker..and made sure that the speaker isn't broken?

I downloaded the manual and schematics this weekend. All the wiring is plugged in and the proper voltages are coming in to each board. There are no visual burn marks on the sound board at all.
 
And you have tried adjusting the volume pot? I know..its rarely that easy..but never hurts to try.
 
You will need the schematics and a logic probe to check all the IO chips and the CPU and PIA chips as well as the audio amp. All of which frequently flake out.

If you set up the diagnostic screens to the sound test and press the up/down button on the coion door, the sounds will cycle through and test each of the data lines on the serial connector between the MPU board and the sound card. From there you need to test the data buffer chips (4049 or 4050 IIRC) if you are seeing the data toggle at the PIA, then test the traces between the PIA and the DAC. If you are seeing these toggle, then you might want to replace the amp chip.

If you lose data along the way, just replace the last chip and see if it gets any further.

ken
 
There are a couple of things about the sound setup on Sinistar that are different from most other Williams games using that same sound board. First, Sinistar uses a speech board, if the speech board isn't there or is disconnected you won't get any sound (without rejumpering the sound board). The other thing is that there is no test routine in the Sinistar sound ROM, so the normal test switch doesn't do anything. To test the board you need to ground the input pins.

Start by checking the voltages at the test points - TP1 and 2 are the rectified input voltages, TP3 is ground, and TP4 is +5v. Then, jumper the volume pot as shown on this web page and try grounding input lines:
http://www.arcadesolution.com/sound.html
 
WOW! Thank you for the highly detailed responses! I am going to try my best to wrap my head around them both and get troubleshooting.

Thank you very much!
 
Another unlikely but still possible problem: Check the actual speaker or speaker connection. My Food Fight sound went out once, and it turned out it was the connection to the speaker...It still appeared to be hooked up to the speaker, but when I touched it, it immediately crumbled and fell off.

I repaired the wire and everything was fine.

You never know... ;) .

If nothing else works, try Andre from arcadesolution.com. Recommended!

He also has a self help page up on Williams soundboards here:

http://arcadesolution.com/sound.html

Might be useful.

Good luck!

Jon
 
Success! After following the guide from Arcadesolution.com, I was able to determine the 6808 was bad. I had a spare sound board and swapped the chips to test.

Thank you very much for the help everyone!

I HUNGER!!!
 
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