DECWriter II

From: will emerson <wpe_at_interserv.com>
Date: Tue Jan 6 21:12:22 1998

Tony Duell wrote:

> >
> > > I saw a DECWriter II today near the trash. It was a typewriter-style thing
> > > bolted to a table. I didn't stay around long, because there was a security
> > > camera watching (what are they for above the trash anyway, for god's sake?). I
> > > couldn't have dragged it away, or put it anywhere, anyway. So, what did I
> > > miss?
> >
> > A nice hardcopy terminal, apparently with a stand.
>
> Nice? I personally don't care for the things...
>
> It's a 7 pin dot matrix printer with all the electronics in the stand (2
> main boards - PSU/motor drivers/head drivers and control logic. I suppose
> it's useable, but I'll keep my KSR43 and DECwriter 100, thanks...
>
> There's an interesting design 'feature' in the LA36 (DECwriter 2).
> There's no carriage end-stop switch. What happens is that the carriage
> hits the end stop, stalls the motor, and no pulses come from the shaft
> encoder on the motor. The control logic detects this and switches off the
> motor.
>
> Now, what tends to happen is the plastic keyway in the carriage belt
> sprocket fails. The control logic returns the head to the LHS, but the
> motor keeps turning, slipping in the sprocket. It keeps on running into a
> much heavier load than normal, until the motor overheats, the insulation
> burns off, and the fuse fails.
>
> I had one where the carriage motor drew 4A with no load (it's normally <<
> 1A). I had to rewind the motor - one afternoon of my time was a lot less
> than what DEC charged for a new motor! I think I still have that motor
> somewhere...
>
> >
> > Tim.
> >
>
> -tony

    FWIW, I remember the LA-36.... We used the LA-120 (the next generation?) as
our "standard" console in our datacenter (DECsysten-10's, DECsystem-20's, VAXen)..
I used to HATE the LA-100's that used to ship with the vaxen as factory supplied
console terminals. I remember after one certain VAX was installed, I asked my
supervisor if I should swap out the LA-100 with a spare LA-120. Words to the
effect were "why?"... I stated that I felt that the thing would last about a week...
"Nawh, leave it, It'll be fine" (rough quote)... Well, two nights later, the third
shift
operator came in, just as I was getting ready to leave. In his zeal to strip a line
printer, he managed to "hip check" the LA-100 that was sitting on a wooden
box (actually a support we used to elevate the LA-120 consoles so we could
comfortably use them in a standing position) that was serving as it's stand. The
resulting impact with the floor, immediately rendered the LA-100, for all intents,
and purposes, useless. I don't know if, now, VAXen tend to crash when their
console terminal "goes south" for any length of time, but, back then (days of
VMS 4.<mumble>), after about two minutes or so, you had a hung system...
Never moved a LA-120 so fast in my life... Oh, my boss heard what happened.
When asked "when they fix th' 100, you want me to swap it back?", the answer
was a brief "Nope!". I actually have one of those "evil" LA-100's.. Glad I overcame
my dislike for th' thing..

                                                                          Will
.
Received on Tue Jan 06 1998 - 21:12:22 GMT