OT-sortof: Replacing incandescent panel lights

Roy J. Tellason rtellason at blazenet.net
Sun Jan 1 17:28:39 CST 2006


On Sunday 01 January 2006 03:19 pm, Chuck Guzis wrote:
> While not directly germane to vintage computers, I can see that this might
> have some real interest for those restoring old displays.
>
> I've got an old (1990) 120w-per-channel receiver in which I've just
> replaced the hybrid power amp module--I think I can expect another 15 years
> or so of life out of it.  What bothers me is that some of the incandescent
> 12vdc back-of-panel lamps are starting to go.
>
> They're soldered onto small PCBs and are the small 25 ma variety.  They
> illuminate the back of small LCD displays that have an orange filter on
> them, so the color is basically that of an NE2 neon.
>
> I was thinking of replacing the lamps with high brightness LEDs and current
> limiting resistors--since the bulbs are paired up, I'd put the 2 LEDs in
> series with a single resistor.
>
> Now for the questions:
>
> 1.  Has anyone tried to do this?
>
> 2.  Will LED's have sufficient brightness and dispersion to substitute for
> incandescents in this application?
>
> 3.  What would the best LED to use?

I carry the yahoo "amateur-repairs" list here,  and that topic comes up fairly 
often -- apparently folks are doing it,  all right,  but in those cases 
mostly for meters,  and wanting white light are using white LEDs.  Orange 
filter?  Use orange ones...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin




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