Popping noise in PC monitor

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Popping noises (sounding like they might be coming from a loose
connection) are coming from the back of my PC monitor (CRT).  The image
on the screen shrinks then the screen goes black and then the image
returns.  I've checked the plug and it isn't loose.

What's going on?

Re: Popping noise in PC monitor

"gary" wrote:
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    That started happening with my Dell 19" CRT monitor
    about 6 to 8 months after I bought it - a loud POP! with
    a collapsed image which gradually returned.

    I thought it might be dust settling on some high voltage
    circuitry, so I blew into the case with an air compressor
    hose while sucking up the dust with a vacuum cleaner hose.
    The popping stopped for a month or so, then it started
    up again, but less frequently.  I blew out the case again,
    and the popping has not recurred in 6 years.


Re: Popping noise in PC monitor

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That is normally arcing in the FBT. That screen size effect proves
that. The FBT generates that high voltage that drives the screen.

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The FBT is dying. It isnt usually economic to replace it.

Re: Popping noise in PC monitor

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That is the high voltage arcing over.

Call a TV repair shop or drop in to a TV repair shop, and
ask them what success rate they have with fixing HV arcing.

I have a monitor with this problem, and the arcing was on
the body of the flyback transformer. The big red HV wire
in the monitor was fine. In some cases, if there is a crack
in the insulation, only replacement of the component will
fix it. In other cases, cleaning and chemical treatment
might give temporary relief. A TV repair shop can advise
on the odds of being able to fix it.

Don't waste your time trying to catch sight of the arc inside
the monitor. I tried, and even with a video camera pointed
at the open top of the monitor, I could not see the arc
happening on video tape. Since the arc only happened once
every couple hours, I also couldn't stand there long enough
to eyeball it.

You might wonder what my solution was. I found that
reducing the resolution and refresh rate of the monitor,
can help. On my monitor, apparently the magnitude of the
high voltage is reduced, when the resolution drops. I
had arcing while at 1280x1024 resolution, and no arcing
at 1152x900. I operated the monitor for several years
at the reduced resolution, and no more arcs. For me,
that was cheaper than shipping it to an authorized
repair center.


Re: Popping noise in PC monitor

gary wrote:
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Probably dust inducing high voltage arcing.  Clean it out.  Beware
high voltage shocks.

Chuck F (cbfalconer at maineline dot net)
   Available for consulting/temporary embedded and systems.

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