On Wed, 20 Dec 2006 17:18:48 GMT, Grinder
<grinder@no.spam.maam.com> wrote:

>Previously I had come to alt.comp.hardware to seek speculation about the
>failure of a Gateway FPD1800 LCD monitor. The monitor was exhibiting a
>pronounced reduction in brightness, most noticeably at the top edge and
>diminishing down the screen. By the middle of the screen, brightness
>appeared to be normal.
>
>Paul was very helpful in suggesting that it might be the CCFL at the top
>edge of the panel that had failed. Opening the booger up and swapping
>the top and bottom lamps produced the same symptoms as before--a fade
>from the top towards the bottom. Perhaps it's my speculation alone, but
>that leads me to believe that it is the inverter, that drives the lamps,
>that has gone Wilbanks.
>
>I've taken that inverter out, and noticed something odd about it.
>
>http://home.mchsi.com/~grinder/temp/inverter-96.jpg
>
>The leftmost transformer (TM-008) appears to have vented. It doesn't
>show up so well in the picture, but the corner of the board adjacent to
>that transformer is globbed up with a crust that appears to have flowed
>from the transformer.

Transformers don't generally vent, except maybe the super
large liquid filled type... which that is not. It's hard to
tell from the small picture but it's probably just flux
residue left on during manufacturing, that has turned an
unpleasant color from long term exposure to moisture, dust,
and heat.


>The odd thing, though, is that transformer is
>closest to the connectors that feed the properly driven CCFLs. I cannot
>specifically tell if that transformer is for the adjacent lamps, but it
>makes ergonomic sense. At any rate:
>
>Q1) Is it worth trying to replace this transformer?

Probably not. If I were to gander a guess, it'd be more
likely a FET or diode that went out, providing the caps
hadn't failed, but the same are used on both lamps and one
works, and neither "seems" to look bad from the picture.

What I'd probably do is take a stiff toothbrush and some
alcohol/detergent mix, and scrub all the crud/flux/etc off
the board, briefly rise it off, shake it to get bulk water
out that may have wicked into the transformers, and let it
air dry for a few days.


>I think my soldering skills are up to it, but are there realistic odds
>that this would cure my problem?

Can't tell for sure from the picture but if the transformer
is through-hole rather than surface mount, removing it
should be a piece of cake, just use desoldering braid, a
bulbed pump, or a spring-loaded sucker (if no fragile
surface mount parts very near the pins on the back).


>
>Q2) Where can I get the replacement part?

Determine if you need one at all... pull the transformer off
and check winding resistance (for shorts)... though since
it's high(er) voltage, it's possible to get some arching a
multimeter wouldn't pick up as a short.


>I've looked into getting the whole inverter, but have had no joy.
>InverterCentral.com reports a replacement part (KVBNKM045A) for an
>FPD1800, but that cannot be right--it's much too large to fit into the
>space provided. (Also, that company seems a little flaky. No one
>answers the live chat, and even though a toll-free number is often
>referred to on the site, there's none to be found.)

If you feel comfortable soldering *anything*/everything, the
form factor doesn't matter so much as sourcing parts. Get
what you can as discrete parts but if it turns out a part
can't be sourced or identified, you'll have to see what else
is available. If you can ID parts (I can't see how this is
controlled, whether another chip on the back or ?) you might
be able to reverse engineer it enough to figure out if a
suitable generic with similar form-factor will fit (In the
monitor case location (and mounting studs if you don't want
to have to fabricate a new standoff... something we can't
see nor determine your willingness to go to lengthly
efforts).

BTW, PC Connection has a low-end HannsG 19" for $100 + S/H
after rebate... to put cost and time into perspective. If
you don't care about being able to adjust brightness, you
might be able to pick up some random small invertor board,
though given how many LCDs are almost blindingly bright when
set to 100% brightness, it might not be ideal.



>
>The panel inside of the FPD1800 is an LG LM181E3 (A2). I've found a
>technical spec for that panel. It plainly states that "the inverter is
>an external unit to the LCD." I can find no markings on the inverter
>that suggests its maker or part number, other than a tiny sticker on the
>backside that has "0112" and "17324M" on it.

You might measure the dimensions and keep looking on the web
& ebay, there may be other monitors that have used same or
similar enough.