front panel LED help sought

drlegendre . drlegendre at
Wed Jan 14 20:44:25 CST 2015

Howdy gents,

On Wed, Jan 14, 2015 at 3:28 PM, Alexandre Souza <
alexandre.tabajara at> wrote:

> Jay, leds hasn't changed much from years ago. Electronicaly, i believe any
> led of same size/format/color will fit.

As one who has recently rebuilt an early 70s Altair 8800, I can inform you
that a great deal has changed, in the LED world.

The very inexpensive 'standard' red LEDs which I obtained to replace the
failed units in the Altair were magnitudes brighter than the original
parts, when fed from the same power sources. I ended up having to increase
the value of the series resistors by hundreds or even thousands of ohms,
just to maintain a similar level of brightness vs. the old LEDs.

I'd have to take a look inside, but I believe the values jumped from 300R
to several K in most cases. The new tech is so much more efficient than the
stuff kicked-out in the 70s!

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