29 Feb
2008
29 Feb
'08
10:46 p.m.
Jules Richardson wrote:
Brent Hilpert wrote:
(.. just reminds me the 'LAMP TEST' button used to be a standard feature on
control consoles, in general; and the 7447 7-seg decoder has a lamp-test input.)
Don't know if it correlates with the sort of equipment you saw, but I agree
with Chuck the mission control consoles in the pic he provided look like
film-projection displays, the numerals are too well-formed. I have one
frequency counter using that type of display.
The earliest *off-the-shelf* 7-segment display
modules that I've run across are
from ca. 1967:
http://www3.telus.net/~bhilpert/tmp/dialco7seg/
As can be seen, they use neon bulbs. The displays themselves are not dated but
other component date codes in the instrument they came out of were in the range
66xx-67xx.
Now that looks like the sort of thing I saw in the mock-up (unfortunately
there's a lot of reflection in the photo that I took from the perspex screen
they'd covered the model with, so it's probably not worth sharing).
It's impossible to tell from the mock-up exactly what type of technology it
was though; it was just the seven-segment nature that surprised me, as I don't
think I've seen it that early elsewhere (everything was either Nixie or stacks
of side-lit perspex plates with proper formed numerals on them).
Interesting point from Chuck about the possible failure mode of 7-seg's
though. Perhaps they never thought of that!