Re: bizarre monitor failures

From: Juhan Leemet (juhan_at_logicognosis.com)
Date: 07/20/04 

Date: Tue, 20 Jul 2004 18:50:11 -0200

On Tue, 20 Jul 2004 12:24:28 -0700, M Berger wrote:
> Lenard <lenard@127.0.0.1> wrote in message news:<pan.2004.07.20.13.26.39.104280@127.0.0.1>...
>> On Mon, 19 Jul 2004 20:46:18 -0700, M Berger wrote:
>>
>> > Sounds logical. Incidentally, I have other components plugged into the
>> > same outlet (on the same surge protector)...
>>
>> Most surge protectors use a MOV for protection (usually good for one
>> shot). The surge protector will protect your equipment attached from a
>> high voltage electrical spike(lighting strike). It will not protect
>> your equipment from momentary electrical noise (electrical static).

Won't protect from overvoltage (surge) or undervoltage (brownout) either.

>> > 1) If the power supply to this outlet is unstable, why aren't the
>> > other components affected? Are CRT's just more delicate or
>> > susceptible to power disruptions?
>>
>> Maybe they are, but the damage is being reduced, converting AC to DC
>> with the voltage level being lowered (120-v AC to < 22-v DC) and
>> dissipated as heat energy. The monitor on the other hand is converting
>> some of the electrical energy to a higher voltage level to drive the
>> CRT (the screen). Both the 'normal electrical current' and the
>> 'electrical noise current' are amplified increasing the potential for
>> damage instead reducing the potential as the laptop AC adapter does or
>> the power supply in the tower does.
>>
>> > 2) Could I be overloading this outlet with these components and could
>> > that have contributed to the damage?
>>
>> ...depends on a great number of things...
>
> I checked it -- not hot.
>
> Thanks to all for the very informative answers. The problem does seem
> electrical in nature, as opposed to being caused by software or the
> video card. By the way, today the weather is nice and dry (low
> humidity), and the blackout problem hasn't occurred once so far after 4
> hours of use.

You might consider getting a UPS, some of which switch (programmable?) to
battery power either on overvoltage (surge) or undervoltage (brownout).
There are a bunch here recently that are selling pretty cheap. This should
stabilize the AC voltage being delivered to the CRT. I'm thinking that
CRTs should also have "universal power supplies" these days? I guess they
don't though? Probably because it's too expensive to crank up the hiV?

Maybe monitor the line voltage? See if there are big variations?

> I'm going out to buy a humidity sensor.

It would give you more information.

BTW, that reminds me. I'm living in St. John's, NF, by the Atlantic Ocean
and it also gets humid here (depending on which direction the wind is
blowing). I have noticed that my Sony monitor(s) occasionally/rarely make
a hiV "snap" and the screen goes black, and then slowly comes back into
view. Seems like that is high voltage arc'ing due to humid air being more
conductive. One of those monitors eventually failed totally. Familiar?

Humidity might be the crucial factor? 

-- 
Juhan Leemet
Logicognosis, Inc.

Relevant Pages

  • Re: Whole House Surge Protector
    ... I don't believe that the type of surge protectors you are referring ... to would do much to protect sensitive electronics anyway. ... Do oyu have a recommnedation for a WHSP? ...
    (alt.home.repair)
  • Re: Whole House Surge Protector
    ... If you've never had a problem with line lightning, ... I don't believe that the type of surge protectors you are referring ... to would do much to protect sensitive electronics anyway. ... Some WHSPs come with attachments to protect CATV and telephone lines. ...
    (alt.home.repair)
  • Re: bizarre monitor failures
    ... > Most surge protectors use a MOV for protection (usually good for one ... It will not protect your ... > are amplified increasing the potential for damage instead reducing the ... > surrounding wall they you should have it check by a qualified electrician. ...
    (comp.os.linux.hardware)
  • Re: bizarre monitor failures
    ... Most surge protectors use a MOV for protection (usually good for one ... It will not protect your ... equipment from momentary electrical noise. ... surrounding wall they you should have it check by a qualified electrician. ...
    (comp.os.linux.hardware)
  • Re: How to PostMortem?
    ... > Five types of power problems exist. ... > what the UPS claim to protect from. ... they switch over to battery operation even if the voltage is ... If line voltage goes below 100 volts, ...
    (comp.os.linux.setup)