Quoted from stibbsd:
I just got the Williams World Cup (1978) pinball machine from my sisters’ basement. It had been stored in a couple of boxes for the past 18 years. The batteries were still in the CPU/MPU, but I got them out and cleaned it up pretty well. There were a couple of fuses blown, but most of the wiring looks stable. However, I have a few existing problems. First off – I’m not an electrician and I will avoid soldering anything if possible. Also - this is my first pinball machine.
I’ve spent several hours with the manuals I’ve found online and seen a lot of pictures that match my machine. I’ve learned the diagnostics process and run through it several times to test everything I can find. Here’s the problems I have left to identify:
The sound on the machine is not functioning at all. I grabbed another speaker to make sure that wasn’t the problem When I run through test sequence 2 all the items seem to work except anything that should be playing a note through the sound board.
1) Verified 10J1, 10J2 and 10J3 are connected – cleaned them and re-seated them.
2) Checked the 10F1 fuse – it is fine.
3) Tried a different speaker.
4) Turned the volume up and town – I get a hum in the speaker when I touch the volume control – same as the new speaker as well.
5) I’ve run the tests on both the sound alternator settings.
Is there anything I can check before trying to replace the sound board? I’m looking for any suggestions to get this pin back to working order.
Send a picture of your sound board front side.