The PP pins send and receive 5v signals depending on the pin. What worries me about this controller is that it has no opto isolation and so your computer is vulnerable. You should be glad that you have a PP card as it is easier to replace than a motherboard. Everything points to a spike going back to the PP. The pinout diagram shows the capabilities of each pin. How they are used depends on the controller. If it were my controller, I would replace the driver board with a BoB and three drivers, but it is a lot of work to cure what could be a simple fault.