[R-390] LED lamp replacement

[Cecil Acuff]

Hi Group,

        Strange thing about my R-1051 LED conversion...no two seemed to come
out the same....even though the same LED's were used and installed the same
way....never did figure that one out....worked well though and was much
cheaper than trying to put the original lamps in.

I agree with Bob though...I have seen the R-390A lamps available at the
local electronics supply house...readily available...and cheap....relative!

Cecil....
----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: "Tom Norris" <r390a at bellsouth.net>
Cc: <R-390 at mailman.qth.net>
Sent: Tuesday, July 06, 2004 9:49 AM
Subject: Re: [R-390] LED lamp replacement


> Hi
>
> Well I guess I run the risk of getting thrown off for mentioning this
> but the issue with the LED lamps is more or less the same as some of
> the solid state ballast replacements. (duck and run for cover ....).
>
> When you convert AC to DC to run the LED's the current is only going to
> flow in short little pulses when the AC waveform is higher in voltage
> than the DC turn on point of the LED. The pulsing of the current
> creates noise clear up into RF. The R-390 was not designed to be
> shielded against this sort of thing going on inside the radio.
>
> If you decide to go the LED lamp route I would suggest that a separate
> wire routing power for the LED's would be a good idea. Then come up
> with as quiet an AC to DC conversion as possible and stuff it off in
> the power supply module. At least that way it's as far from the IF and
> RF as possible. Just for the record, yes I stole that idea ....
>
> The nice thing about the LED's is you can get an awful lot of light out
> of them these days. I have an R-1051 with an LED conversion in it that
> works very well.
>
> The illumination angle coming out of an LED is more narrow than the
> angle of light coming out of the bulbs we normally use. One solution to
> this is to do violence to the front end of the LED. The other is to run
> multiple LED's. If you get your DC off of the 25 volt AC line then you
> can put quite a few LED's in series ....
>
> Since the bulbs for the 390 are still commonly available and fairly
> cheap I'm not sure I would do all this work on a 390. If and when the
> bulbs get into the $40 a bulb category like the R1051 bulbs then we'll
> have a bulb replacement thread on here that goes on and on forever.
>
> Take Care!
>
> Bob Camp
> KB8TQ
>
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