Kill LCD Noise

Subject:
          Re: [WS] kill LCD noise
    Date:
          Sun, 12 Sep 1999 13:08:56 -0400 (EDT)
   From:
          David Evans <[email protected]>

nc-reibolto wrote:
>
> Does anybody know a possibillity to kill this noise ?
>
> Perhaps it4s possible to install an ON / OFF switch for the display?
>
> between wich wires of the display I have to install it ?  (wich color ?)
 

  It's not the display but the backlight that makes the noise.  Even if your
backlight has basically faded to nothing the noise will remain.
  If the A/D is like the keyboard version there will be two connections to the
display: the normal ribbon cable going to the CPU board (or somewhere similar)
and a smaller two or four conductor cable going to the power supply.  This is
what powers the backlight.  You'll notice that if you disconnect it the noise
will go away.
  Simply install a switch on this line and you'll be all set.  This might be
a good idea anyway since if you only turn on the backlight when you're working
you can prolong its life.  When I get around to replacing my display if I can't
make the LED version fit I may try to replace the contrast pot with a combo
pot/push-button that would let me turn the backlight on and off.