PowerMac 7200/75 and "Open Firmware"

From: Christopher Smith <csmith_at_amdocs.com>
Date: Thu May 2 10:07:00 2002

Ok guys,

I'm pretty sure this isn't quite on topic yet -- but it is
somewhat old for a PowerPC model.

I have a 7200/75 which was given to me because it had a
problem with its video. I cleaned the mainboard with isopropyl,
and got all of the dust bunnies out, and it's worked fine since
then. :)

I've been trying really hard to get the thing to give me an
"open firmware" prompt, but have had no success.

Right now I have a "converted" vga monitor plugged in, a Mac ADB
keyboard/mouse, and an IBM terminal connected to the "modem" port,
set to 38400bps, 8 data, 1 stop bit, no parity. The cable has
been used recently on a SPARC, so I'm pretty sure it's good.

I have tried a Wyse-50 terminal, too, which I know is good.
(However, I'm not completely certain that the IBM terminal works
as I imagine -- I have it in ADM5 emulation mode right now. I
may try to put the Wyse back on it.)

I installed OS 8.1 on the disk yesterday. I got it to fit in
a 50M partition (barely -- what ever happened to being able to
fit MacOS on a floppy?), and I got a copy of the "boot variables"
control panel.

I have tried to hit command-pretzel-o-f at bootup. It works, but
the screen just stays black, and I can't get anything from the
terminal. I have tried with and without a null-modem adaptor,
since I'm not sure which way the serial port goes.

I also tried setting the input device and output device with the
"boot variables" control panel. I've tried:

Input: ttya
Output: ttya

Input: kbd
Output: screen

Input: kbd
Output: /chaos/control

Now, first, let me ask: Might the control panel not function properly
if it's not in the "control panels" folder? I've just got it setting
around on the drive, but it _seems_ to work. Not that I can actually
see the "open firmware" stuff to make sure it's actually doing anything.

Next:

Any ideas what I'm doing wrong? Has anyone else ever gotten this to
work?

Eventually I want to install Darwin on this system, and use the terminal
on the "modem port" for all console operations.

Chris

Christopher Smith, Perl Developer
Amdocs - Champaign, IL

/usr/bin/perl -e '
print((~"\x95\xc4\xe3"^"Just Another Perl Hacker.")."\x08!\n");
'
 
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Received on Thu May 02 2002 - 10:07:00 BST