Here’s the final installment on Game Plan’s Super Nova. This is a sound issue that was present the entire time and the last issue I fixed before packing it up to ship out.

There were three things going on. First, in attract mode, every 15-20 seconds the game would make a “dunt!” sound. The spinner made no sound and the background sound was missing despite turning it on via the dip switches.

Interestingly, the sound board has a jumper to enable or disable the background sound. As you can see in the schematic below, the jumper actually physically disconnects the background sound section output from the amplifier (marked CONSOUND on the chip that generates it). It was moved to the disable position, when I enabled it, the background sound ran constantly and seemed off pitch which is probably why it was disabled.

After studying the schematics I figured out which pins I could short to activate or deactivate sounds. When I shorted the pin to stop the background sounds, it stopped. By starting and stopping all the sounds manually, I was able to determine that the sound board was good. When I tried shorting pins at the logic board, all got a response from the sound board except one.

Back to the connectors, I found a wire just about to pull out of a connector pin. One more connector to rebuild. After replacing one more connector all is well again, for now…..

Thanks for reading, if you liked this, found value or learned something please share it.

Frank