I hope you've tried the obvious, e.g. <F1>
or <DEL> during the POST sequence to
enter BIOS setup? The earliest PC/AT's used a setup diskette to do the setup of
the CMOS-based parameters. That may prove to be a problem.
Yes, I get into the CMOS-Setup, but in there I cannot change the values
for memory and when I switch the power on the BIOS only tests the first
640Kb of memory ...
To start out, I'd leave the "turbo"
switch alone. However, there's usually a
Turbo indicator LED that will tell you when you're in TURBO mode. If there's no
TURBO button, there's probably a jumper connection available somewhere, and
these connections are normally located in the lower left region of the board
(assuming the power and keyboard connections are at the upper right, for
reference. When you say "not available" do you mean you don't have one, or
that
it's not present/supported on the motherboard?
I put the board into a modern AT-Box - there's no turbo button or
turbo-LED.
I'm curious about one thing ... Why is it that you
believe it to be operable at
12 MHz? Is the CPU marked as such? Can you tell anything about the support
chip set? I vaguely remember something about a Morse '286 around here
The clock on the board shows 24Mhz, so I assume the the CPU works at
12Mhz. I don't have the board right here and I cannot remember what chip
set is used.
someplace. It's possible that there's a
manual, but more likely it's a board
that was hying about. I may not have it anymore, but you never know ...
There's a web-site mentioning the board, but the link to some manuals is a
dead link :-(((
Cheers,
Mario