I have this card that came with an IBM 5150 I found at a flea market a few years ago that I'm just starting to work on

(click for big)

It has a few functions:

- 256k of expansion memory (with the ability to use as a RAM disk)
- Serial and parallel ports
- Realtime clock
- A terminal emulator in ROM

When I got it the clock battery had leaked (but there didn't appear to be any corrosion spreading at the time) so I removed the battery, and then I put this and all the other 5150 stuff away because I didn't have a monitor that could display MDA/Hercules (it came with both, Hercules installed and MDA in the box the Hercules came in). A while later I got a trisync CRT for a different system, which still isn't MDA compatible but I found an EGA card in my parts drawer so I was able to fire up the machine. It booted fine when configured just to use the 256k of RAM on the motherboard but when I set the jumpers to 512 to include the 256k on the systemcard I got the 40XX 201 error, meaning it couldn't see any RAM above the 256k onboard. I noticed some corrosion I had missed on the legs of the 8250 UART (large chip next to where the battery was) so I pulled it out to try to clean it and some of the legs were so badly corroded they popped off. I ordered a replacement 8250 and this got the 5150 to see the full 512k of RAM. A few days later I got a DOS boot disk and ran debug, which showed the serial port and parallel port were where they should be at 03F8 and 0378.

One of the many floppies that came with this system was a Kraft driver for a serial trackball and a copy of a paint program that Kraft bundled with it, but no trackball. I wanted to mess around with this and also figured it would be a good way to test the Systemcard's serial port so I found that model of trackball cheap on ebay. Now I have it but I'm having problems, the driver refuses to load. It has a few command line options:

C# - Specify COM 1-4
Z - Use Aux port
T - Transpose IRQ (between 3 and 4)

When trying to specify the (any) COM port I get the error "COM(X) is not available"
When using the Z option I get "Aux port not detected"
When running with no arguments I get "Mouse not detected"
The transpose switch has no effect on any of these.

There's a bank of 8 DIP switches on the Systemcard, and I can't find a guide to them anywhere, which I find really weird for a Microsoft product. Through trial and error I found that SW6 changes the COM port from 1 (03F8) to 2 (02F8) and SW8 changes LPT from 1 (0378) to 2 (0278). Switches 1,2,4, and 5 seem to have something to do with RAM as I get 201 errors if I mess with them. SW3 is strange as when it's off I get nothing on the display (but the PC still boots and seems to POST). SW7 doesn't seem to do anything. Regardless, changing the COM port address did nothing for my problem. The configuration the switches were in when I got the card, and what works as far as memory and debug seeing the ports is 11100101. I should note that right now I have no way to get any other software on this machine so I can't test other drivers etc. I did test a generic serial mouse that I know works and got the same result. The only other card in the machine besides the drive controller and EGA is a Kraft Joystick port, and removing it doesn't change anything.

I'm wondering if anyone more knowledgeable than me regarding truly ancient PCs could shed some light on what's going on here, or if anyone has the manual for the MS Systemcard, I'd be really interested in reading the whole thing but even just the DIP switch settings would be a huge help.