Mountain Computer music system for Apple II plus computer.Fully working, all 16 channels. Light pen works.Original flex cable between the boards had deteriorated due to age so I replaced it with a pin and socket connector.Tested with a rev -07 Apple motherboard.
I did test with a newer RFI rev motherboard and its memory gets intermittently corrupted when the music system is active.It could be there is a problem with the music system hardware or my RFI motherboard, but I don't have any other boardsto verify. I suspect there is a compatibility issue between this older hardware and the newer Apple motherboard.Works absolutely flawless with my -07 Apple motherboard.
Software and manual can be found online.