3 Oct
2015
3 Oct
'15
12:40 p.m.
On Oct 2, 2015, at 10:21 PM, ethan at 757.org wrote:
Hello everyone,
I'm working to troubleshoot a 286 laptop style computer. I've kind of hit the
end of my knowledge and wondering if anyone has any insight.
The computer in question I've never seen run. So I don't know normal behavior.
There were a few caps inside that were leaking electrolyte, I cleaned it all up and
replaced them. A few traces look a little bit corroded but test fine.
First thing I'm thinking, is did the BIOS eproms loose a bit or two of data from
age? Bit rot? I did read off the two BIOS chips (high and low pair I assume.) I can see
text like Copyright Pheonix Technologies 1988, but I can see that for instance the first
character of the text Copyright is wrong, it's a P in one file and 9A in the other.
Second thing I hooked up Oscope and cut on computer. It never does a floppy seek. When I
poke around the 27c256 EPROM I see constant activity on all address lines, and all
datalines. This includes the OE pin as well. Would a normal runnng computer hit the BIOS
that much?
Any thoughts appreciated!
--
Ethan O'Toole
When you drop into BIOS, is anything actually set? Can you set the time, and get it to
stick?
I have a Twinhead 386sx/16 I bought new, the only thing I've used it for in the past
20 years is a serial terminal, and every time I go to boot it, I have to drop into BIOS,
and configure things, as the BIOS battery is long dead.
Zane