7 Nov
2014
7 Nov
'14
9:55 a.m.
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's
having a bit of trouble moving the carriage assembly and I can't find a
service manual for this thing. (It's similar in some respects to the
DECwriter IV, but the mechanical parts appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of
the platen to the other via a cable attached to a servo motor on one end
and a pulley on the other; in the middle of this cable is a small metal
ball -- this ball is (as far as I can tell) meant to sit in a small
"cup" on the underside of the carriage and when the cable moves, the
ball pulls the carriage along. I'm assuming this was done this way
since the Correspondent is meant to be portable, and allowing the
carriage to break free of the pulley mechanism would probably reduce
damage in the case of a sudden shock (like getting dropped.)
So far so good -- unfortunately the vast majority of the time, the ball
leaves the carriage behind (especially on carriage return) and I can't
quite figure out what's out of tolerance -- the carriage appears to move
smoothly, nothing is bent out of shape or broken as far as I can tell,
and there's plenty of tension in the cable. There's also not much to
adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem)
with the print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
7 Nov
7 Nov
1:22 p.m.
Josh,
is there a spring clip missing someplace? I know nothing about that system but your
description just makes me think that, and often springs are the first to corrode or rust
to the point that they fall off.
- Mark
On Nov 7, 2014, at 11:55 AM, Josh Dersch <derschjo at gmail.com> wrote:
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's having a bit
of trouble moving the carriage assembly and I can't find a service manual for this
thing. (It's similar in some respects to the DECwriter IV, but the mechanical parts
appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of the platen to the
other via a cable attached to a servo motor on one end and a pulley on the other; in the
middle of this cable is a small metal ball -- this ball is (as far as I can tell) meant to
sit in a small "cup" on the underside of the carriage and when the cable moves,
the ball pulls the carriage along. I'm assuming this was done this way since the
Correspondent is meant to be portable, and allowing the carriage to break free of the
pulley mechanism would probably reduce damage in the case of a sudden shock (like getting
dropped.)
So far so good -- unfortunately the vast majority of the time, the ball leaves the
carriage behind (especially on carriage return) and I can't quite figure out
what's out of tolerance -- the carriage appears to move smoothly, nothing is bent out
of shape or broken as far as I can tell, and there's plenty of tension in the cable.
There's also not much to adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem) with the
print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
3:33 p.m.
On Fri, Nov 7, 2014 at 1:22 PM, Tapley, Mark <mtapley at swri.edu> wrote:
Josh,
is there a spring clip missing someplace? I know nothing about
that system but your description just makes me think that, and often
springs are the first to corrode or rust to the point that they fall off.
It's possible that something's missing, but it definitely didn't rust off.
This thing is in immaculate condition (I'm not sure it was ever actually
used). If something fell off, it's not rattling around anywhere that I can
see, but it's certainly possible.
Thanks,
Josh
- Mark
On Nov 7, 2014, at 11:55 AM, Josh Dersch <derschjo at gmail.com> wrote:
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's
having
a bit of trouble moving the carriage assembly and I can't find a
service manual for this thing. (It's similar in some respects to the
DECwriter IV, but the mechanical parts appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of
the platen
to the other via a cable attached to a servo motor on one end
and a pulley on the other; in the middle of this cable is a small metal
ball -- this ball is (as far as I can tell) meant to sit in a small "cup"
on the underside of the carriage and when the cable moves, the ball pulls
the carriage along. I'm assuming this was done this way since the
Correspondent is meant to be portable, and allowing the carriage to break
free of the pulley mechanism would probably reduce damage in the case of a
sudden shock (like getting dropped.)
So far so good -- unfortunately the vast majority of the time, the ball
leaves the
carriage behind (especially on carriage return) and I can't
quite figure out what's out of tolerance -- the carriage appears to move
smoothly, nothing is bent out of shape or broken as far as I can tell, and
there's plenty of tension in the cable. There's also not much to adjust
here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem)
with
the print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
8 Nov
8 Nov
1:03 a.m.
I will take a look at our specimens in our collection. we have one with
a acoustic coupler and one without.
On 07-11-14 22:22, Tapley, Mark wrote:
Josh,
is there a spring clip missing someplace? I know nothing about that system but your
description just makes me think that, and often springs are the first to corrode or rust
to the point that they fall off.
- Mark
On Nov 7, 2014, at 11:55 AM, Josh Dersch <derschjo at gmail.com> wrote:
--
Met vriendelijke Groet,
Simon Claessen
drukknop.nl
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's having a bit
of trouble moving the carriage assembly and I can't find a service manual for this
thing. (It's similar in some respects to the DECwriter IV, but the mechanical parts
appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of the platen to the
other via a cable attached to a servo motor on one end and a pulley on the other; in the
middle of this cable is a small metal ball -- this ball is (as far as I can tell) meant to
sit in a small "cup" on the underside of the carriage and when the cable moves,
the ball pulls the carriage along. I'm assuming this was done this way since the
Correspondent is meant to be portable, and allowing the carriage to break free of the
pulley mechanism would probably reduce damage in the case of a sudden shock (like getting
dropped.)
So far so good -- unfortunately the vast majority of the time, the ball leaves the
carriage behind (especially on carriage return) and I can't quite figure out
what's out of tolerance -- the carriage appears to move smoothly, nothing is bent out
of shape or broken as far as I can tell, and there's plenty of tension in the cable.
There's also not much to adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem) with the
print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
10 Nov
10 Nov
7:39 a.m.
hey there,
Today I got some time to take a look at our correspondent and guess
what, there should be a brass clip to hold the ball:
https://hack42.nl/gallery/v/Museum/2014-11-10-693.jpg.html
I could not take the clip off. wiggling it also moved the spring holding
the print needle block.
simon
On 07-11-14 18:55, Josh Dersch wrote:
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's
having a bit of trouble moving the carriage assembly and I can't find a
service manual for this thing. (It's similar in some respects to the
DECwriter IV, but the mechanical parts appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of
the platen to the other via a cable attached to a servo motor on one end
and a pulley on the other; in the middle of this cable is a small metal
ball -- this ball is (as far as I can tell) meant to sit in a small
"cup" on the underside of the carriage and when the cable moves, the
ball pulls the carriage along. I'm assuming this was done this way
since the Correspondent is meant to be portable, and allowing the
carriage to break free of the pulley mechanism would probably reduce
damage in the case of a sudden shock (like getting dropped.)
So far so good -- unfortunately the vast majority of the time, the ball
leaves the carriage behind (especially on carriage return) and I can't
quite figure out what's out of tolerance -- the carriage appears to move
smoothly, nothing is bent out of shape or broken as far as I can tell,
and there's plenty of tension in the cable. There's also not much to
adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem)
with the print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
--
Met vriendelijke Groet,
Simon Claessen
drukknop.nl
3 p.m.
Thanks a ton for going through the trouble on this, it's much appreciated.
I'll have to go through mine and see if that clip somehow ended up wedged
somewhere inside. Otherwise, I guess it can't be too hard to build a
replacement.
Thanks again!
Josh
On Mon, Nov 10, 2014 at 7:39 AM, Simon Claessen <simski at dds.nl> wrote:
hey there,
Today I got some time to take a look at our correspondent and guess what,
there should be a brass clip to hold the ball:
https://hack42.nl/gallery/v/Museum/2014-11-10-693.jpg.html
I could not take the clip off. wiggling it also moved the spring holding
the print needle block.
simon
On 07-11-14 18:55, Josh Dersch wrote:
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's
having a bit of trouble moving the carriage assembly and I can't find a
service manual for this thing. (It's similar in some respects to the
DECwriter IV, but the mechanical parts appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of
the platen to the other via a cable attached to a servo motor on one end
and a pulley on the other; in the middle of this cable is a small metal
ball -- this ball is (as far as I can tell) meant to sit in a small
"cup" on the underside of the carriage and when the cable moves, the
ball pulls the carriage along. I'm assuming this was done this way
since the Correspondent is meant to be portable, and allowing the
carriage to break free of the pulley mechanism would probably reduce
damage in the case of a sudden shock (like getting dropped.)
So far so good -- unfortunately the vast majority of the time, the ball
leaves the carriage behind (especially on carriage return) and I can't
quite figure out what's out of tolerance -- the carriage appears to move
smoothly, nothing is bent out of shape or broken as far as I can tell,
and there's plenty of tension in the cable. There's also not much to
adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem)
with the print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
--
Met vriendelijke Groet,
Simon Claessen
drukknop.nl
12 Nov
12 Nov
10:37 a.m.
On Mon, Nov 10, 2014 at 3:00 PM, Josh Dersch <derschjo at gmail.com> wrote:
Thanks a ton for going through the trouble on this,
it's much appreciated.
I'll have to go through mine and see if that clip somehow ended up wedged
somewhere inside. Otherwise, I guess it can't be too hard to build a
replacement.
Thanks again!
Josh
Just a quick update on this -- I opened the Correspondent up and went
through it with a flashlight and found the clip wedged in a rear corner,
behind some wiring. It had at some point gotten ripped off the underside
of the carriage (along with most of the plastic post it was screwed to). I
glued it back into place and the terminal is operating much better now but
still has some issues -- when the carriage reaches either end of the platen
it starts twitching rapidly back and forth and the terminal stops
responding to input. It sounds like some sort of sensor issue, perhaps the
logic is confused about exactly where the carriage is. Time to do some
debugging, I suppose :).
Thanks again,
- Josh
On Mon, Nov 10, 2014 at 7:39 AM, Simon Claessen <simski at dds.nl> wrote:
hey there,
Today I got some time to take a look at our correspondent and guess what,
there should be a brass clip to hold the ball:
https://hack42.nl/gallery/v/Museum/2014-11-10-693.jpg.html
I could not take the clip off. wiggling it also moved the spring holding
the print needle block.
simon
On 07-11-14 18:55, Josh Dersch wrote:
Hi all --
Got myself a nice looking DECwriter Correspondent (AKA the LA12). It's
having a bit of trouble moving the carriage assembly and I can't find a
service manual for this thing. (It's similar in some respects to the
DECwriter IV, but the mechanical parts appear to be fairly different.)
The carriage assembly (print head, ribbon) is carried from one end of
the platen to the other via a cable attached to a servo motor on one end
and a pulley on the other; in the middle of this cable is a small metal
ball -- this ball is (as far as I can tell) meant to sit in a small
"cup" on the underside of the carriage and when the cable moves, the
ball pulls the carriage along. I'm assuming this was done this way
since the Correspondent is meant to be portable, and allowing the
carriage to break free of the pulley mechanism would probably reduce
damage in the case of a sudden shock (like getting dropped.)
So far so good -- unfortunately the vast majority of the time, the ball
leaves the carriage behind (especially on carriage return) and I can't
quite figure out what's out of tolerance -- the carriage appears to move
smoothly, nothing is bent out of shape or broken as far as I can tell,
and there's plenty of tension in the cable. There's also not much to
adjust here so I'm kind of puzzled.
I've put up a few pictures (and a short video demonstrating the problem)
with the print head/ribbon removed here:
http://yahozna.dyndns.org/scratch/la12
Anyone ever worked on one of these before? Any ideas?
Thanks as always,
Josh
--
Met vriendelijke Groet,
Simon Claessen
drukknop.nl
3645
days inactive
3650
days old
6 comments
3 participants
participants (3)
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derschjo＠gmail.com -
mtapley＠swri.edu -
simski＠dds.nl