[Premium-Rx] 2050 Backplane Lighting

[Vittorio De Tomasi]

GandalfG8 at aol.com wrote:

> I have a Rohde and Schwarz test set that uses small filament bulbs in
> recesses at either end of the display. These don't last indefinitely
> and are a real pain to replace so I intend to use white LEDs, high
> brightness if necessary, once I finally get round to the significant
> dismantling that will be involved.
> Whilst I accept that the R&S will be easier, in the sense that it was
> intended for some form of illumination and the PCBs already designed
> to accept it, I can't see it would be that difficult to mount similar
> LEDs along the edges of any LCD display. I'm intending to try that
> with my non backlit 1792 and if the resulting high spots are too
> obvious then I'm sure I'll be able to find some translucent adhesive
> tape to act as a diffuser.
> regards
> Nigel Clarke
> 

Since today I opened my Sangean ATS909 to replace the IF filters (a
non-premium receiver, but it has a backlighted LCD!), I noticed that the
backlighting in the Sangean is done exactly that way, using two small
green LEDs placed on the "short" sides of a 90 x 50 LCD. The material
used to spread the light to the LCD seems to be lucite (a transparent
material often used as a light pipe for coupling together optical
devices like photomultipliers), however I bet that plexiglas can work as
well. The lighting of the display is pretty uniform and seems to me
enough to read display when there is no direct light on it. If only I
had a 2050 at hand to try this on its LCD....

vy 73

Vittorio ik2czl
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Vittorio De Tomasi         ik2czl at amsat.org    http://www.detomasi.it

"Qui errat circa principia, impersuasibilis est" - St. Thomas de Aquino