From: Steve Robertson <>
Date: Mon Dec 13 09:39:04 1999

Well, I went and picked up the NCR Tower 400 this weekend.

The 400 is about the size of a LARGE tower PC. I haven't measured but, it's
about 28" inches tall, 24 inches deep, and 7 inches wide. I'd guess it
weighs about 75 pounds.

As with all new aquisitions, the first thing I did was open it up, remove
all the cards, blow out the dust, check for missing or damaged parts, and
then reinstall everything. The 400 is a 20MHZ 68020 machine built on a
4-slot multibus backplane. This particular system has 20MB of main memory,
60MB tape drive, 120MB hard drive, 10 serial ports, 2 SCSI interfaces, and
2 serail printer ports (each port will support 4 printers). Based on the
date codes on the chips, this machine was probably built in late 1985.

I reassembled the system and spent HOURS trying to get it to talk to a
terminal. The system has a funky 15 pin connectior for the console and no
documentation. I had to trace the connections back to the CPU and was able
to determine which were inputs and which were outputs based on whether they
went to a 1488 or 1489. After much tinkering, I was finally able to get the
system to send data to the terminal during boot.

NOTE: It uses a 9600 baud, 7-bit, and no parity.

Spent another 3 or 4 hours and was finally able to get the terminal to talk
to the system. Whoopee!!! Finally got data going both ways.

Unfortunately, the system still won't boot the OS. The sequence goes
something like this:


The system hangs at the DK5 message. Since I'm not seeing any disk
activity, I'm sorta assuming the "DK5" refers to a disk activity. If anyone
can confirm this, I'd appreciate it? It isn't a big deal because I'll be
getting the 450 in a few weeks and if the 400 doesn't work, I'll have a few
spares for the 450.

I got a look at the 450 while I was there and it looks more interesting.
Physically, it about twice as "thick" as the 400 and probably weighs twice
as much. Didn't look inside but would assume it has a 6 or 8 slot multibus
backplane. I believe it will support 16 terminals.

The good news is that the 450 is still in daily use so, I know it'll work
when I get it home. The system will be available in a couple of months and
I'll send an update once I get it.

Neither machine is really all THAT interesting but, I don't have any other
multibus systems and kinda wanted one.


Steve Robertson - <>
Received on Mon Dec 13 1999 - 09:39:04 GMT

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