"DoN. Nichols" wrote:
On 2012-02-22, Michael A. Terrell wrote:
I'm talking about the all mechanical cash registers that were the
main products of NCR. The had several large buildings in the Dayton
area that were machine shops cranking out all the parts to feed their
assembly plants. They started building them over 100 years ago.
O.K. I thought that we were still talking about the NLS digital
voltmeter readouts. :-)
Sorry, I thought 'NCR' was enough information. Of course I grew up
near there and knew some employees.
How about the line printers (not HP) which had a drum of letter
forms rotating and a solenoid driving a hammer on the other side of the
paper to drive it into the ribbon. Early ones had all the letters lined
up, but tended to fail with the massive current surge when you printed a
line of all '*' or all '_'. The latter, btw, made a nice "tear here"
weakened point. :-)
We had a large DataProducts drum printer on the SATE for the PRC-77.
It would shake the entire computer booth when it printed a line of
asteriks to signal a failure. I was there one day when the engineer
from Data general was doing a core dump to the printer. it didn't have
a refolder, so the paper was sraying off the ceiling. ;-)
Years later, I had to scrap a tractor trailer load of those printers,
along with a trailer full of VAX based CAD systems that had come off
lease. The owner wanted cerified destruction to keep them off the
market. It made me sick to trash the uncased NTSC studio grade
monitors. but the contrast said they could not be resold. A lot of small
TV stations would have paid $1000 each for them, for spares.
I wonder why they make the polarized DC versions? Perhaps
brighter? I didn't see a clue that the AC ones cost any more -- though
they *should*. :-)
Probably for the anal retentive types? Also, it would allow for
simple bicolor indicators, by simply inverting the polarity if two are
wired in parallel.
but colored lamps would eliminate the need for
those tiny colored silicone rubber covers.
The ones which tended to tear when you tried to pull them over
the rim of the bulb sleeve, or when you pressed on them to eject a bad
bulb. :-) Who was it -- Honeywell -- who made those switch assemblies.
I know that MicroSwitch made the snap-on switch elements.
Master Specialties. I may still have a new switch or two left.
http://www.marineairsupply.com/catalogs/10_Series.pdf
I first saw the 327/328 lamps on a tour of the VOA Bethany facility
while it was being upgraded from the original design. It was one tech's
job to wander around the facility to test & replace bad lamps. There
were over 3,000 in use, and they were still installing new equipment.
With a pushbutton on each panel to light all bulbs on that
panel? There were such on the flight simulator instructor's control
panel which a company I worked for for a while made.
They used the switch itself, with the console in diagnostics mode.
He would just push a switch, then pull it out with what looked like an
IC extractor and replace a bad lamp, and test again.
--
You can't have a sense of humor, if you have no sense.