[TenTec] Better Bulb Life in TenTec 229, 238 Tuners

[Barry N1EU]

I have discovered the secret to eternal bulb life in the 238.  You
can't beat eternal.

http://lists.contesting.com/archives//html/TenTec/2003-12/msg00217.html

73,
Barry N1EU

On Thu, Feb 14, 2008 at 1:10 AM, Jim Brown K9YC
<k9yc at audiosystemsgroup.com> wrote:
> I do several things to make these bulbs last longer and get more
>  brightness from lower current (long life) bulbs. First, I put white
>  tape on the inner black panel below the dial and around the bulbs
>  (all the black paint that isn't visible through the glass) to better
>  reflect the light up to the tuning dial. That improves brightness.
>  Second, I use 756 bulbs, which draw only 80 mA at 14V and are rated
>  15K hours. (The "standard" 1815 bulb draws about 300 mA and is rated
>  only 3K hours.) Third, to further improve life, I run them at
>  slightly lower voltage by adding one or two forward-biased 1A diodes
>  in series with the DC feed from the RCA connector.
>
>  If you don't have 756 bulbs, you can still add multiple diodes in
>  series with the standard 1815 bulbs. That will also reduce brightness
>  a bit, and improve life quite a bit.
>
>  FWIW -- I've tried multiple LED's in each opening with series R to
>  limit current in one 229 tuner. LED's last OK, but I have not been
>  happy with the result visually.
>
>  73,
>
>  Jim K9YC
>
>
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