Northstar Update

From: Anthony Clifton - Wirehead <wirehead_at_retrocomputing.com>
Date: Sun May 16 19:16:58 1999

OK, I ran through the Integrated Systems tests in the Northstar
Horizon Computer System manual and I've discovered a few things.

1. I don't think it's the floppy drive or the controller or the
disks. According to the steps that I completed successfully, the
problem is most likely with the RAM conflicting with the PROM
address on the MDS-A3 disk controller.

2. I pulled ALL the RAM out of the machine, as per the instructions,
and put just the RAM A3 (16k N* card) into the machine for testing.
BUT, after testing, I pulled it out and found one of the bypass caps
is broken off at the board surface (easy fix).

QUESTIONS:

I can repair the RAM 16 A3 but I don't have the switch settings and
jumper settings (J) to set it to start at 2000H. What are these?

Also, I have a RAM 16 A2 board that I can try. Are the switch settings
and the jumper settings on it the same as the A3 to start at location
2000H?

Finally, will NSDOS run in 16K ram? I see no indication in the manuals
that it won't but it's a good question to ask anyway.

Thanks...

Anthony Clifton

>I pulled the Northstar Horizon out of storage now that I have time
>to take another crack at restoring it. It has an MDS-A3 controller,
>which I connected to an MPI-52 full-height 5.25" drive. When I boot
>it, I can hear it jiggle the heads a few times (a good sign generally)
>but then it just spins the disk for a minute (I can't hear the heads
>moving) and then stops.
Received on Sun May 16 1999 - 19:16:58 BST