23 Dec
2000
23 Dec
'00
1:18 p.m.
Date: Sat, 23 Dec 2000 14:02:58 GMT
From: pete(a)dunnington.u-net.com (Pete Turnbull)
Subject: VT78 - lots of questions
Is there anything in particular I should watch out for when I power it up?
This is an area of discussion. The full treatment is to inspect, reform big
electrolytic capacitors (put a current limited voltage on them for a while),
then separately test the power supply, then attempt to power up the cards.
The other is to visually inspect, apply power for a short while, and
if nothing bad happened apply power longer and try to run it.
I don't have the RX01 drives that originally came
with it, but I do have
the connecting cable with a D-37 connector at the VT78 end and a DB-25 at
the other end (only 18 pins fitted). I also have a set of RX02s in the
adjacent rack, and I have the RX02 print set and manuals somewhere. I
assume I can set the RX02 (M7044) switches appropriately, and use that with
an appropriate adapter cable? Anyone know the relevant VT78 pinout?
My VT78 is running off of RX02's set to RX8E mode. They also have the
DB25 plug on the back which will connect directly to the VT78 cable. If
yours don't I should be able to dig up the pinout if you don't run across
it in one of the manuals.
Documentation: all I can find that's even vaguely
relevant is the DECscope
User's manual, RX8/RX11 Floppy Disk System User's Manual, RX8/RX11 Floppy
Disk System Maintenance Manual, the OS/8 Software Support Manual, and a
FOCAL-GT/RT User's Manual. I have borrowed copies of the Small Computer
Handbook (that's the one for 8/e, 8/f and 8/m) and the PDP8/a Minicomputer
Handbook. I should have the RX02 User Manual somewhere too. What else am
I going to need, that's downloadable from the net?
I have WPS, RX02 and OS/78, and COS manuals online. I have a complete VT78
printset but I have not scanned it yet.
http://www.pdp8.net/query_docs/query.shtml
What is FOCAL-GT/RT?
I should have some 8" floppies, though I'm not
sure what's on them because
I've not actually found them yet :-) Is there anything I should try
downloading from the net?
I have OS/78, COS and WPS images online, poke around in ftp://pdp8.net/images/
If you have a OS/8 variant on the floppy that may be able to use my disk
image dump and restore programs, dumprest.zip in
ftp://pdp8.net/software/
I have never actually tried to use it on the VT78, I write the images
from the 8/E.
If you find you don't have any bootable floppies I can make you one.
My VT78 has gotten a little finicky, it sometimes needs a couple of power
cycles before it runs right. Yet another thing for the todo list.
David Gesswein
http://www.pdp8.net/ -- Old computers with blinkenlights