(continued from previous post) […]
(continued from previous post)
One of the machines had 14MB of RAM, the second had 6MB and the last had only the standard 2MB so I modified that one by removing the proprietary SIMM slots from the RAM expansion board and making a small sub board with standard 72 pin SIMM slots. I then wired that to the RAM expansion board giving 14MB on that machine (2x2MB +1x8MB SIMMs).
On that same machine I mounted two extra ISA cards in the space where the hard drive was (A network card and a sound card) and used the two standard ISA slots for other ISA cards
This meant that I couldn't use the same space to mount the CF card on that machine so I came up with an alternative mounting which used a different type of CF adapter with a very short IDE extension cable bent around the adapter so that it could be mounted directly above the IDE socket.
I had to patch the BIOS to support some of the above changes:
1. Change one of the HD types to 528MB
2. Detect and initialise the Cyrix and TI 386 to 486 upgrades so no driver software was required in the OS (code skipped if 386 processor detected)
3. Detect a slave CF card on the IDE port and initialise the CMOS correctly
4. Change the external floppy type from 5.25" to 3.5" so that the external GOTEK drive on the printer port worked correctly (The original T5200 external floppy was 5.25" so the BIOS always assumes that when an external floppy is detected)
I also made a custom version of XTIDE to work with the BIOS to support large CF cards (The standard version of XTIDE made Windows 95 run in MSDOS compatibility mode and also stopped Windows 2/386 and Windows 3.0 from running at all)
Finally, to make use of the large CF cards I used grub4dos to make a multiboot system so I could boot virtually any OS that would run on the system.
If anyone wants any further details on any of these mods, please let me know.