There were only a small number of games that supported any of the Apple II sound cards such as the
From those games that used the Mockingboard, did any of them utilize the on-board VIA's timers or interrupts for anything?
Or, were all of the games straight PORT A/B access from the CPU?
From the schematics I've seen, the IRQ line is attached to one VIA and the NMI is attached to the other VIA. But I have no idea if any games utilized them.