6 Jan
1998
6 Jan
'98
12:12 p.m.
Tony Duell wrote:
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...
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
.
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.
Tim.
-tony