[R-390] LED lamp replacement and Fake Ballasts

[Tom Norris]

Lee brings up a point, though I know it
was tied to the humor thread rather than
to the technical part of the thread that
died horribly long ago...

A while back there was a company selling
cheap cheap little fm radios with fake tubes
in it. Each tube had a dim orange LED so
it would "glow"

I suppose if we were bored, we could do
the same thing with a "ballast replacement"
resistor, just wire the LED in parallel
with appropriate dropping resistor
and rectifier diode since it is AC.
Stick some sort of diffuser in the top
of the tube shield (so the glow is *dim*
from  the top of the shield ) and replace
the tube shield as normal.
This would actually be practical in that
it would indicate an open filament in
either the BFO or PTO tubes..... Hmmmm.

Now to the light replacement idea --

When I get the 390A back together
that is strewn around the room, I'm
going to replace the dial lamps with white
  LED's so I'll not have to ever replace them.
Already did it on the "spare" 390A, and it
works well - *very lightly* sand the tip and
the front half of the LED to "frost" it a bit
to diffuse the light.

Superbright red LEDs might look good too.

UV leds make the meters glow *brightly*
but I don't wanna take a radioactive meter
apart to install one inside!

73

Tom