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Grex Hardware Item 196: Monitor LG 700E - very bright
Entered by veek on Fri Nov 30 04:41:39 UTC 2007:

Wanted to know what the problem is. The monitor was flickering (white,
horizontal lines that came and went) and it's brightness flickered.
Thought it was a voltage problem, but now it's very bright and steady.

I have bright and contrast = 0.

6 responses total.

#1 of 6 by veek on Fri Feb 15 14:28:03 2008:

Could someone tell me how to open up the LG Studioworks 17". I know
enough to be very very EXTREMELY super wary. I couldn't find any screws
at the rear of the monitor, but when i rotated the monitor 180deg and
placed it on it's top, the plastic faceplate of the monitor has tiny
plastic lever like things that you can push down on (and i think that
would slip off the face plate). What i wanted to know was if that was
the place to open it up at? It seems dangerous to be opening up the
front rather than the rear (I'm closer to the CRT and the risk of
implosion because of the tube breaking).

Anyway, all i want to do is take a look at what's inside, identify the
various parts, put the cover back and take it to the repair guys.

#2 of 6 by veek on Fri Feb 15 14:56:10 2008:

And what i noticed was that, when i look at the base of the monitor,
there is a slot like thing for a screw-driver but no screws. I was
wondering is i should insert a thin screwdriver and trip some latch?

#3 of 6 by gull on Thu Feb 21 17:57:00 2008:

You're very unlikely to implode a modern CRT accidentally, especially by
damaging the screen end.  The glass there is very thick.  The most
fragile part of a CRT is the "neck" portion at the back.

I don't know what to tell you as far as getting it open.  All the
monitors I've taken apart had recessed screws in back.  (Sometimes very
deeply recessed.)

#4 of 6 by veek on Sat Feb 23 05:07:34 2008:

Hey Gull. I've been a bit nervous about the whole thing because someone
on USENET said that the HV inside can get past surgical gloves. I'd also
wear shoes but i think it's best to take it to the repair guy and ask my
dad to pay for a TV repair course instead of doing it in this half assed
fashion.

If you know of any GOOD books that deal with TV Repair for the Noob,
please let me know. I did check Amazon, but there were some bad reviews
for the popular books and I couldn't decide anything.

#5 of 6 by gull on Mon Feb 25 19:00:03 2008:

The main high voltage point you'll come across is the CRT anode
connection, which is on the rear side of the flared part of the CRT. 
It's generally covered by a rubber suction-cup like shield.  The voltage
there can range from 3kV for small back and white sets to as much as
50kV on large color ones.  You wouldn't have to deal with that unless
you were replacing the CRT or the flyback transformer, though; just stay
away from that point and you'll be OK.

Another issue is that most TVs do not use isolated power supplies.  This
can present a shock hazard from 120V (or 240V, depending on what country
you live in) from just about any point on the circuit board.

Surgical gloves aren't really helpful in preventing shocks.  For one
thing they're too easily punctured by sharp terminals.

#6 of 6 by arthurp on Sat Mar 29 06:07:52 2008:

I like the description of the anode given above.  It is very dangerous.
 There is a safe and reasonable way to ground this out.  A needed step
as the charge can stay trapped in there for weeks after the last time
power was provided to the unit.  This should be described in any good
repair guide.  I took a shock from a similar voltage but with much less
total charge from an engine.  It knocked me down and my arm was
paralyzed for about 20 seconds.  Not to mention the pain.  At least my
heart kept going.  :)

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