H.T.F.C.

On May 9, 5:43 pm, Paul <nos...@needed.com> wrote:
> trunterzx wrote:
> > One day when I came back to use the computer, which was switched on, I
> > kept pressing the keyboard but nothing came onto the monitor. I
> > switched off the power and switched on again, the screen came out for
> > a while, and went off again. So I decided to unplug the power plug of
> > the monitor and plug it back, and somehow the problem was solved. But
> > now, the problem came back, and now unplugging and plugging the
> > monitor power can no longer solve the problem... Is my monitor spoilt,
> > or does the problem lie somewhere else?
>
> > Please help! Thanks.
>
> You don't say whether your monitor is an LCD, but I'll assume it is.
>
> The monitor has a backlight inside it. The LCD panel controls
> the transmission of light, and there is a light source behind
> the panel.
>
> The majority of LCD monitors have one or more CCFL (cold cathode
> fluorescent) lamps for backlights. They need 700 to 1000V AC to
> operate. A small rectangular circuit board has an "inverter",
> which converts a low voltage like the 12V DC inside the monitor,
> to the required high voltage AC to run the lamp. The AC is
> also at a high frequency, so there won't be any flickering.
>
> If the monitor lights up for a second or two, and then goes
> dark, that is the inverter shutting off. It means the
> inverter thinks it is overloaded, and so it has shut off.
> This can mean a failure of the inverter, or an actual
> short somewhere in the wiring (like dust or dirt forming
> a conductive path for the high voltage to flow). Sometimes
> the connectors on the inverter are corroded and make an
> unreliable connection.
>
> One test you could have tried, if you could still see the
> monitor screen, is turn down the intensity setting of the
> monitor. If you can do that, frequently the inverter will stay
> running for a while longer. But it won't last forever.
>
> This is really a shame for LCD monitors, because
> everyone worries about the CCFL (the lamp itself)
> and its 25000-35000 hour lifespan. But what seems
> to happen instead, is problems with the inverter
> mean never getting to see the lamp wear out.
>
> Inverters can be replaced - the hard part is finding
> an exact substitute. There are companies on the
> web that sell substitutes, but you never know how
> close they are to functioning like the original.
> I doubt any company sells the exact same module
> as the one inside your LCD monitor right now.
> If only the LCD monitor companies sold replacement
> parts, or were required to by law.
>
> Paul

Paul, thanks for taking the time to give all this very interesting
info on monitors. It's nice to know what's really happening "in
there". :-)
ATB
sandy58