On  5 Jan 99 at 0:23, Gordon Tyler wrote:

> Hi. My 19" Hitachi monitor, which is 12 months old & has been on
> 24/7 since new but generally on blank screensaver for 20 hrs/day
> has been intermittently emitting a high frequency (~15000 HZ ?) low
> decibel level sound over the past several weeks. The sound emits
> for perhaps 15 min every hour or so, & I find it quite irritating.

  Most North American adult men can't quite hear sounds pitched that
high, but many women can.  It was a typical frequency of some of the
monitors supported by the old CGA cards, and *may* have been
responsible for some of the problems attributed to monitor
"radiation".

> Is this something I can adjust? Something similar occurred with my
> Sony 25" TV & I recall tweaking an internal setting a few years
> ago & the noise permanently disappeared, but I don't recall what I
> did.
>
> The noise seemed to start when I installed SP4 on NT4.0 WS. I
> restored my old SP3 image on the NT partition because too many
> other problems occurred, so all my old settings were resumed
> with absolutely no other problems, video or otherwise. I've tried the
> built-in degauss, switching the monitor off, changing refresh rates,
> but the sound still intermittently occurs. It will stop immediately if
> I blank the screen with the screen saver.
>
> I also noticed on booting that as the different screens display prior
> to NT log-on, a slight squeak of similar tone occurs, as if a switch
> needed oiling (!).

  The video adapter is going to come up in something that looks kind
of like a CGA text mode, and should switch -- often with a slight
"klunk" sound (a relay switching), to the mode set by the video
driver.

> If anyone could help me with this problem or direct me to a resource,
> I'd be grateful.

  At a guess, the relay that switches between various frequencies may
be flaky, occasionally "leaking" incorrect signals.  Yuck.
  Several local places will diagnose and fix most monitor problems
for a flat price that I don't mind paying.  This may be a symptom of
the local level of competition, and this might not be an option in
other regions.

  You mention that it changed when you installed SP4.  Is there any
chance that the sound is coming from the speakers and not from the
monitor?  I know that I sometimes hear the sound of interference on
the sound card caused by proximity of the video card, and clearly
related to certain kinds of video activity (or lack of same).
  If you can, see if this monitor does this on another system; see if
this system does it with a different monitor.


David G

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