DECwriter Correspondent (LA12) mechanical issue...

[Simon Claessen]

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