From: ard(a)p850ug1.demon.co.uk (Tony Duell)
>May I ask a very simple question. What machine are you using this with
(from the description below, I assume a PDP8). If it _is_ a PDP8, do you
have the reader control relay mod fitted correctly? If not, then you
_will_ drop characters I think.
My computer is an 8/L. I do not have the relay fitted at all. After a
careful examination of the schematic and manuals, this relay only forces TTY
power on, in LINE mode (this is redundant if the TTY is already on and
prepared to read a tape), and also forces 115V to the distributor trip coil
so that a tape will immediately start reading if present. Without the relay
a manual start is required by simply flipping the reader lever to "Start".
Everything gets up to speed after one or two characters of leader no matter
how the reader is initiated. No characters will be dropped since the program
will loop indefinitely at the usual KSF, JMP.-1 until a character is
assembled and sent to the TTY receiver card.
>That's very odd. The most obvious mechanical problem would be wear on the
ratchet wheel teeth in the reader. But that would cause problems once (or
n times) for every revolution of that wheel (and the drive sproket) --
Quite. That's why I'm scratching my head!
>So what you're saying is that it sends the correct number of chracters,
but some of them are corrupted to 0's?
Yes, when an error occurs while printing the test tape I can "hear" the
nonprinting character being sent to the typing unit (it "jumps" but nothing
appears on the paper) and the next consecutive char is then printed
correctly.
>Either your read pins are misaligned (they should come through the middle
of the tape holes --
check this), or the contacts are sometimes not making properly.
Agreed. They look centered to me (but what IS the definition of "centered"
i.e. at what point in the read cycle? The tape and pins do not seem
perfectly stationary with respect to one another during the read cycle.)
The manual shows that the sprocket wheel should be rotated forward to take
up the slack against the detent at which point the pins are centered in the
holes. IF I'm reading this right. Actually they show a "Gate Flash" that
looks like a hole on the side of the sprocket, which does not exist in my
reader.
>Try running the reader without tape, with the EOT sensor held down. It
should then send all 1's. Check that it does (use the PDP8 for this with
a similar program to yhe one you've written already, just get it to halt
if the character is not all 1's). Let it run for many minutes.
Excellent suggestion, thank you. I will try this right away.
>A really Heath Robbinson (Rube Goldberg?) trick
Who's Heath Robbinson? I always liked Rube Goldberg's inventions...
>3) focus a camera on the reader mechanism. Set the aperture appropriately
for the flashgun. Make the room dark, hold the shutter open on B, let it run
4) When the flash fires, close the shutter, turn everything off
5) Develop the film and hope that it shows you what the problem is.
-tony
Sounds awfully complicated. Perhaps I can do this with my Sony digital
camera if it has a sync input!
thanks for the tips
-Charles
>Mine has just started having paper getting stuck on the "teeth roller"
>underneath the larger one next to the green felt "hot" area. It needs a new
>smaller roller cause worn out. There are a number of rollers that look like
>this, how do I tell which one it is in order to order the right one?
www.fixyourownprinter.com
They sell a rebuild kit for the LJ2 that addresses the jamming on pickup.
They also have a number of other kits available, for assorted common
jamming problems with that printer series.
-chris
<http://www.mythtech.net>
I have recently come across original -- disks only -- (5 1/4") of Wordstar Pro 4.0, Turbo Pascal, Microsoft Word 5.0 and in 3 1/2" of Microsoft
Presentation Manager. Also manual and 5 1/4 disk for SpinRite. Are these of
interest or should I just toss them?
Jim
jmh(a)slac.stanford.edu
We take standard green-bar or blue-bar and print on the back side.
Larry
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]On
Behalf Of Tom Uban
Sent: Friday, April 11, 2003 3:19 PM
To: cctalk(a)classiccmp.org
Subject: 132 column (14x11) fanfold paper
Does anyone know where 132 column (14x11) white (blank) fanfold
paper is still available? Bowater used to make it years ago, but
has since sold that business off...
--tnx
--tom
Does anyone know where 132 column (14x11) white (blank) fanfold
paper is still available? Bowater used to make it years ago, but
has since sold that business off...
--tnx
--tom
Dear Sir, I have a hp7974A magnetic tape reader and now I can
read/write data on a magnetic tape via gpib+code (by C++) with 1600 PE
density. However, the written data cannot be read our another hp7970B
tape reader due to the fact that It can read the data with 800 NRZI
tape density. As far as I know, hp7970E series can read both. Is it
possible to buy one of it? and did You know where can i buy one?
Thank you.
odemir(a)metu.edu.tr
Apr 11/03
We are looking for 60 pieces obsolete printer ribbons IBM #1040920 for IBM
printer 4772. We are desperate! Can you help?
Thanks and regards
Eric Sperwer
Tel: (954) 438-6622
Hi,
I have few items for HP-85 that I would like to sell.
I have a few of each: 16K Memory Modules, 128K Memory Modules, Serial
interfaces, HPIB interfaces, Modems, Rom drawers with different ROMS,
Manuals and software.
I can ship internationally. I am located in California USA.
To make an offer for an item/s or ask questions please Email
ravid(a)iovega.com. I will not monitor this board for the next week or so.
Please Email me. I also have a lot of other vintage computers, software,
and manuals. (TRS-80, Atari, Apple, Commodore, IBM, HP, and more)
Thanks.
Ravid.
>From: "The Design Fort DTP" <design.fort(a)ns.sympatico.ca>
>
>Hi all,
>
>One thing I was always interested in - and the visitors in my Computer
>Museum often want to know - is how many of the very first personal computers
>are still in existence. By first PCs I mean the following machines:
>Kenbak 1
>Scelbi 8h
>Mark-8
>IBM 5100
>Apple 1
>Altair 8800
>IMSAI 8080
Hi
Missed the Poly88.
Dwight
>
>I know it's quite difficult to figure out how many Altairs or IMSAIS are
>still around. But a search on the Mark-8 e.G. (on the Internet) turned out
>that there are only a handful still in existence.
>
>Greetings
>Herbert
