I want to replace my cmos battery with an external unit, preferably a watch battery or 3 AA's. The battery header has 4 pins and I'm not sure which pins are positive and which are negative. There is also a 3 pin jumper which I believe is for switching from an internal battery to an external. The motherboard is a DTK PTM-1632C with NEAT technology. So far I have swapped the cpu for a 25mhz one, and I was able to find the correct files to use expanded memory through hardware. Hopefully soon I will be playing Wing Commander with expanded memory:D.