Re: [IRCA] Minor Palstar R30CC mod

["Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>]

> > I used three Radio Shack 276-320 white LEDs.  3.6v, 20ma.  All I did was
> > push them into the existing Palstar grommets used to hold the three
> > factory lamps.
>
> Sounds very similar to what I did to my Kenwood FM Tuner a couple of years
> back, only I used high intensity blue LEDs. It turned out that using a
> simple resistor to drop the 28vac down to the needed 9v they would burn
out
> after several hours of use. I ended up using a LM-317 as a constant
current
> source and never had another problem. Looks great at night when the room
is
> dark.

In this case the lamps are fed by a regulated nominal 10v supply inside the
radio.  9.9v actually.  What I should have added is that these three LEDs
are wired in series.  I measured across them, and got 3.3v to ground on the
first, 6.6v on the second and of course the 9.9v on the third.  The 220 ohm
resistor in series with that brings the illumination down to about what the
stock lamps provide.  Next time I open it up, I'll add the 220 ohm resistor
to the feed, and another for a more dim setting.  The current dimmed setting
is perfectly fine at night.

I had tried five Radio Shack 276-351 yellow LEDS (2.1v, 20ma) before.  While
they were rated at 10.4v, they only lasted an hour and dimmed down to
nothing.  I didn't like the yellow hue, so it was no big deal.  I thought
about blue, but the white seemed a better choice for this application.

This was an easy mod.  Pulled out the original lamps and wires used to
parallel them.  Pushed the LEDs into the grommets and wired them in series
and to the original power feed.  Took little time and works well.

I have found the DX Engineering PRA-1 preamp I put inside the R30CC to be a
very useful addition.  Provides excellent sensitivity with small antennas.
The toggle switch on the back turns it off if needed.

No clue what other mods I can make on it.  Maybe a different wide filter,
though the existing ones are fine.  I'd love to add a noise blanker.  I may
research that.

Craig Healy
Providence, RI

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