musicman282
Active member
I've got a Mappy cocktail that has a hum in the audio and was investigating the cause. This machine has a switcher installed and I've noticed that the AC lines are powered on the secondary side of the monitor isolation transformer. Do you think this could be causing my hum issue? The switcher is wired into the old midway linear. When I unplug the connectors to the old linear power supply the hum goes away, but so does the audio itself. Anyone have an idea on what could be causing this? I was thinking about just wiring the switcher into the primary side of the iso transformer and pulling the fuses for the other transformer. I was reading the schematic for the game and can't figure out the audio circuit. I appears that it is using the power supply for amplification??

