A close friend went dumpster diving and was intrigued by a #CPU socket number he didn't know about.
Long story short, I have received a beautiful mid-tower #Pentium Pro 200 MHz for my birthday 😄
Motherboard is an AOpen AX65 with 64 MB of EDO RAM in two 72-pins SIMMs, PCI S3 Virge/DX, 3COM 3C590C, 4.3 GB Seagate Medalist, and the usual CD, CDRW and 3¼" floppy drives.
Boots to NT4 or #MSDOS 6.22 with Win3.11 from NT4's bootloader.
There are issues, though...
(🧵, but slow)
The first two problems quickly appeared when I powered the machine on.
First, the fan of the CPU cooler doesn't spin at all and is even hard to move by hand. Easy fix as I have a spare one lying around.
Second problem is more annoying: after nearly 30 years, the battery in the Dallas DS12887A RTC module is completely dead! I feel safer with a plain replacement than hacking the module open with the Dremel tool to attach an external battery.
The next problem with the #PentiumPro is more serious: the disk drive sometimes makes loud repeated clicks, as if it was trying to imitate an old alarm clock.
I wouldn't be surprised if it was the reason why the computer ended up in the trash.
Also, I couldn't get the the PS/2 mouse to work despite the jumper being set correctly. It could be caused by the RTC battery being dead (there is an option in the BIOS about PS/2 mouse), but I'll need to investigate a bit more.
Back to the CPU fan.
A bit of isopropyl alcohol inside the fan helped dissolve the old hardened lubricant residues and the fan started moving easily again. However, when powered, it would only vibrate. A drop of fine machine oil and it now spins like new!
There were no picture of the AOpen AX65 #PentiumPro board on #TheRetroWeb, so I did my best with my #fp5 and it turned out OK.
I then proceeded to remove the BIOS chip and dump its content with the #minipro.
Now, when dealing with motherboards where the BIOS has a sticker with its version on it, I never know if I should update it in place and make the sticker lie, or replace the EEPROM with a freshly flashed one instead and store the original.
All orders have been delivered, time to replace the the RTC chip on the #PentiumPro motherboard.
Removing the chip went well with the desoldering gun and a bit of help with hot air for the GND pin.
I soldered a socket and used a nwX287 by Necroware. It feels slightly wrong to use a Varta battery in there but I guess that one will be fine.
Amand Tihon