[Elecraft] VERY noisy LCD Monitor. Any Suggestions?

[Nicklas Johnson]

My experience with some cheaper LCD monitors is that the backlight
brightness is controlled by a badly designed PWM circuit.  With my parents'
Samsung, the noise is even audible if you're sitting next to it.

The only solution I've found, if indeed this is what's giving you trouble,
is to turn the backlight brightness up to 100%.  Even at 99% the PWM kicks
in and makes a hell of a racket.

   Nick


On Sun, 26 May 2019 at 12:16, Jim KO5V <ko5v at earthlink.net> wrote:

> Good afternoon,
>
> I have a ~24" LCD monitor that I want to use for logging, to display my
> panadapter, etc. Unfortunately, it is very noisy on HF. When It goes to
> sleep, the noise goes away. This is even more irritating because I now have
> the K2/computer/logging, etc, all working together. I've searched a bit
> on-line, but so far, I have not found any real solutions (but a lot of "me
> too" answers, and one suggestion to ditch the radio and make use of the
> internet...).
>
> There are what look to be ferrite beads on each end of the signal cable
> from the computer to the monitor, and on the monitor end of the power
> supply's low-voltage line (I assume it's a switching supply). There are no
> beads on the supply's power cord.
>
> All the radio equipment and the computer are using the same AC circuit.
> The rig and amp are grounded to the station ground, but the computer and
> monitor are only grounded through the AC supply.
>
> I have four clip-on ferrite beads that I've tried on each end of the
> monitor's two lines, and they make no difference.
>
> Does anyone have any suggestions? Maybe I've missed something dumb. I
> don't mind getting some big cores if necessary, but I would like to hear of
> someone's success before spending a lot of money trying to "shotgun" the
> solution, and I really don't want to get a new monitor - but if anyone has
> a suggestion of a noise-free one, please let me know.
>
> Thanks in advance. 73,
>
> Jim KO5V
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