First post, by FAMICOMASTER
- Rank
- Member
Hello all, it's been an awful long time since I last visited this website. I tried VCFed first, but I was basically told "Get a new one or get an XT-IDE."
I recently bought a bunch of vintage PC clones, since they're vastly reducing in price lately. $200 and shipping and I have two turbo XTs, an AT clone, and a real 512K AT.
To put it shortly, one of the turbo XTs (made by "PC Craft") went up in smoke. The clock battery leaked and destroyed something. Oh well. The 512K AT has a bad power supply and the board still doesn't POST with a good power supply, even with known good RAM chips and a working video card. Not a concern.
The machine I'm here to discuss today is a pretty late AT clone - It's got a 20MHz 286 and 2MB of RAM onboard in one bank of 18 "511000-10" chips. It's got a few issues I'm not sure how to approach.
First of all, I have incomplete documentation. The machine itself is badged "Informate desktop Business Computer." Total Hardware 99 identifies the motherboard as an Informtech International 286/Supra Model C. Link here: https://th99.infania.net/m/I-L/31260.htm
The machine POSTs and boots to DOS after some various disk controller issues (VCfed told me "your disk is bad." The controller was bad, swapping the IBM controller for a WD controller brought it back up). In TH99, the "SW1" switch bank on the motherboard only has 3 switches. Mine has 4. I can't find another similar model, would anyone have any information or maybe even a manual for this / a similar computer? It has an Award BIOS with built in setup, I believe it's on minuszerodegrees somewhere too.
Second of all, I have RAM problems. By itself, the machine only finds 512K of RAM. There's 2MB installed on the board. I have an AST Advantage 128. With 128K on that, I get 640K. With 128K + 512K on that, I get 640K + 512K expanded. With 128K + 512K + 512K, I get 640K + 1152K expanded.
This does not add up at all. According to TH99 the memory switches are set correctly, but they could be wrong. I'll try changing their positions tonight to see if anything improves. There's also the chance that the AST Advantage has issues - I've ordered a Zenith Z445 memory card from eBay (https://th99.infania.net/i/U-Z/54636.htm) which comes in today, so I'll try that as well.
Lastly, there was an LED panel on the front which displays CPU speed. Mine is completely undocumented and also completely dead. There's burn marks on it. Where could I get a replacement?