On 2012-02-24, Michael A. Terrell wrote:

"DoN. Nichols" wrote:

[ ... ]

Ouch! That truly hurts. To what level did they have to be
destroyed? Individual board level in the VAXen? I can understand
trashing the software, and perhaps even the hard disk packs, but at the
generic component level, that is painful. Those could have been used to
repair many non-competing VAXen.


I tried to sell the VAX boards to several service companies, but they
were only interested in PDP-11 parts. They ended up at a refiner to
recover the precious metals.

O.K. So pretty much destroyed. It was not late enough for
there to be a demand for VAX boards.

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.

As long as they could tolerate the full reverse voltage. I
didn't look up the specs on the individual lamps.


Two LEDs, in antiparallel work OK. That's where we get Bicolor LEDS
with two leads. Now they make four lead RGB LEDs.

Depends. If the current limiting resistor is outside the LED
package, yes. Each LED prevents much reverse voltage from being applied
to the other. However, if the LEDs have the resistor (or other current
limiter) packaged inside the lamp assembly, then it gets the full
reverse voltage (unless they also included either a series diode to
block reverse voltage, or a parallel diode to shunt the reverse
voltage.)

[ ... ]

As for the Master Specialties switch/lamp assemblies, you didn't
need an IC extractor, as long as you had fingernails on the thumb and
index finger. Just grab notches in the two ends of the clear front
plate, pull and twist.


The tool helped prevent sore fingers when you were pulling them out
all day long.

O.K.

Enjoy,
DoN.

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