PDP-8/E questions

From: Ben Franchuk <bfranchuk_at_jetnet.ab.ca>
Date: Sun Nov 25 10:28:22 2001

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
Received on Sun Nov 25 2001 - 10:28:22 GMT

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