13 May
2009
13 May
'09
6:56 a.m.
Hi,
I have seen some old computers the last years... But
the VT05 seems to be nearly a phantom. I know
there exist other VT05s.... I have just seen two - in the same pile of stuff. And one is
mine now.
That's the only one I've ever seen working - after repair :-)
As long as you have the DEC reader-run-relay mod (there'll be a 6-wire
cable from the TTY, not 4-wire), you'll do great. If you lack the
RRR, you will probably have issues trying to load software, but you
can punch tape and run software from the keyboard and printer just
fine. There are plenty of 4-wire ASR-33s out there from DEC
installations because they were used for non-console use, say on an
DZ11 or a KL8JA. If you lack the RRR mod, I know I've seen it at the
back of one of the DEC print sets, though I can't recall right now if
it was a PDP-8 print set or an 11/20 printset (I have both and have
read both many times). Don't worry. Most 33's I have are equipped with the
DEC mod. And.. I think you won't get in trouble
without the mod. And... honestly... Loading software via teletype is one of the most time
consuming
excercises I ever did. I sometimes booted a Honeywell H316 via teletype (a unit that has
tty as only
peripheral). It's awful. Loading the CPU test in over half an hour...!! To a 4Kx16
system.
BTW Honeywell used ASR33 with software flow control (XON/XOFF) in a half duplex
configuration. The
reader starts on a XON character and stops after reading an XOFF character. I have only
one machine
in this configuration. If anyone wants to trade one, I could use another one. Can offer a
mint ASR33
or a 35KSR, each with DEC, mod for it!
Perhaps you
never wanted to connect a VT05 needing fill characters to your
system? *g*
In all honesty, no. I don't think I've ever even *seen* a VT05. I've
seen plenty of ASR-33s and lots of VT52s (and plenty more newer
terminals), just not the VT05. In my experience, if you had an older system
(pre-OMNIBUS), an ASR-33
was quite common, though I have used a VT220 with my TTL-era PDP-8s
(because of the included 20mA interface).
By the time the OMNIBUS
came around (1972?),
1970!
the ASR-33 was no longer the "only" terminal
to
use - I've seen a number of -8/e and -8/m with either a VT52 or some
flavor of Tektronix terminal on them. The VT52 was quite common on
the PDP-8/a, and I'd say the ASR-33 much less so, but by no means
unknown.
I don't know... My H316 comes with 33/35 ASR, too.... It's made in
1969.
place for a driver, unlike at the OS/8 prompt. I also
don't recall
the VT05 being pushed in the PDP-8 literature of the day, unlike the
ASR-33 and the VT52.
That's interesting. So I need to get a VT52, too. Will
manage that - I hope...
Now, I finally got an ASR-33 a few weeks ago, and I
want to connect it to
a PDP-8, so I might have to think about this some more! :)
You won't need to
think too much: ASR33 simply works out of the box. Insert
a KL8-E board, hook up the ASR33, run OS/8. If your ASR-33 hasn't been cleaned and properly
lubed (not
over-lubed), you might want to take some time cleaning and adjusting
it. I know I have to tweak on mine once or twice a year, but nothing
really major - just make sure the top and bottom of the letters make
even impressions, make sure the keys all create letters (and send bits
down the wire).
Aha? I never had to adjust anything.. except... The hammer. I
replaced the gum by ugly windings of
electric tape - works like a charm, but has to be replaced every 3 to 4 paper rolls. Take
care not
to ruin your print hammer!!!
On one unit I have rewound the hammer spring to get a better print result (there is NO
adjustment
for the hammer force, isn't there?!?). Not really a funny excercise.
That's all. I primarily was a collector of mechanical teleprinter gear, so I am a bit
familiar with
mechanical digital equipment.
It shouldn't be hard to locate or write an ASCII
echo
program for testing the TTY. It's much more revealing of problems
than trying to type DIR commands in OS/8.
What about local echo?
... And if your 33 is really tooo bad to restore - just throw it away and get another one.
They
stand around in every corner. I did not yet have to throw one away, but...
Still having some incomplete machines (better called fragments) sitting in the basement,
but that's
another story (and it was not me who dismantled them!). They'll go to the dumpster
when I move house
next time. Of course with the important parts (print head, handle, intact cover parts
etc.) removed.
Best wishes,
Philipp :-)
--
http://www.hachti.de