25 Nov
2001
25 Nov
'01
2:28 a.m.
Pete Turnbull wrote:
Agreed. The LEDS are water-white plastic, but
red-emitting. Each has its
leads cut short, about 1/8" from the body, and a small 430R resistor
soldered to the cathode and a wire (probably the trimmed-off resistor lead)
to the anode. (Is this what some people have described as an "LED module"
or is that something more substantial?) They then fit into the bi-pin lamp
sockets. The resistors look like modern miniature metal film, but could be
20 years old.
I don't think aging will be that bad. A tube amp yes, but not a led.
Similar red LEDs cost pennies, maybe 10p. 25p - 35p
with integral
resistor. Bi-pin bulbs of about the right voltage/current/intensity cost a
bit more, about 50p each here. I did think about white LEDs, but they cost
over ?3 each. As Allison says, I would need 28 (plus a bag of spares if I
use lamps) and white LEDs give off a very cold bluish light, quite unlike
the slightly yellow lamps. I thought about yellow LEDs, but they're much
*too* yellow. Then I thought about pairs of LEDs, but that's just getting
too silly.
Since the '?' hints that you are not in the USA , a Red-white-blue
front
panel is out of the question.:) You could color code the display - green
or yellow for each octal digit.
I think I'll stick with the existing LEDs and
maybe "save up my pocket
money" to buy 40 or so bulbs (28 plus a dozen spares).
That is the best idea, since you still will have working front panel
to help with checking that pdp-8 is up and running.
Pete Peter
Turnbull