front panel LED help sought
jwest at classiccmp.org
Wed Jan 14 21:02:45 CST 2015
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!
In my case, I'm not replacing just a few LEDs, I'm replacing every one of them. As a result I have a much wider tolerance aesthetically as to the brightness. That being said, I don't want to blast the room and hurt my eyes looking at them ;)
The ones I'm going to be looking for have axial leads at least 1.5" long, and the bulb diameter is 4.6 or 4.7mm (with the slightly wider collar at the bottom). I'm hunting....
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