According to the manual, the SPR-4 itself uses about 1/3 of the
electricity of the three #47 lamps in it. This IMHO makes it a prime
candidate for replacing them with LEDs. Mine are burnt out and I don't
have any spares.
There are several problems with doing so. The first is that when the
receiver is run on AC the lamps are powered by the main power
transformer, before the rectifiers. Two of them are in series. The
third lamp is in series with a resistor which approximates the load of
the "missing" fourth bulb.
The other more obvious problem is color. If you look at the pictures
of an SPR-4 with the "lights on", on the Universal Radio web page, you
can see that the S-Meter and Tuning displays are blue, while the
crystal switch (in the middle) is clear for the selected crystal and
blue around it. I assume that I can use white or blue LEDs for the S-
Meter and Tuning, but what do I do for the crystal switch?
A blue LED would not do, it would just be blue on blue, which would be
almost impossible to see. A white LED, which all the ones I can get
are very blue, would be similar. Maybe a white and red LED together?
Are the such things as "warm" white LEDs?
Since I plan on using it soley on AC power, should I just give up and
try to find some bulbs? It's in good shape electricaly, but it looks
like it sat in a dusty storage area for 20 years. I've cleaned it up
but it will never be a collector's display item.
Geoff.
--
geoffrey mendelson N3OWJ/4X1GM
Jerusalem Israel [email protected]
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
