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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