On Mon, 3 May 2010 20:18:13 -0700 (PDT), saber850
wrote:

So I tried various techniques to try reproducing the problem today,
all to no avail.

I don't mean to be overly critical, but I think I see a problem. You
remind me of something I had to deal with when training technicians in
a past life. I referred to it as "Circle the wagons. The Indians are
attacking". This was in reference to the tendency for some techs to
march around the problem area, gain a little more insight, but burn
huge amounts of time going literally in circles. The Indians never
had a chance, after tiring their horses, by going in circles around
the wagons. Both you and the attacking Indians would be far more
effective with a direct assault on the problem. At some point, you
will need to dive into the LCD monitor and get your hands dirty. No
amount of additional insight or diagnostics are going to prevent this
from happening. Even if you isolate the problem to a single capacitor
and totally undestand the failure mechanism, you'll still need to
crack the case and do the necessary parts replacement. Might as well
get it over with now (before your horse gets tired).
http://www.ccl-la.com/blog/index.php/samsung-214t-repair/


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

So I tried various techniques to try reproducing the problem today,
all to no avail.

I don't mean to be overly critical, but I think I see a problem. You
remind me of something I had to deal with when training technicians
in a past life. I referred to it as "Circle the wagons. The Indians are
attacking". This was in reference to the tendency for some techs to
march around the problem area, gain a little more insight, but burn
huge amounts of time going literally in circles. The Indians never
had a chance, after tiring their horses, by going in circles around
the wagons. Both you and the attacking Indians would be far more
effective with a direct assault on the problem. At some point, you
will need to dive into the LCD monitor and get your hands dirty. No
amount of additional insight or diagnostics are going to prevent this
from happening. Even if you isolate the problem to a single capacitor
and totally undestand the failure mechanism, you'll still need to
crack the case and do the necessary parts replacement. Might
as well get it over with now (before your horse gets tired).
http://www.ccl-la.com/blog/index.php...ng-214t-repair


Excellent points, that need to be repeated often.

They're related to the issue of whether you're trying to figure out exactly
what's wrong, or simply getting the unit working again. Often (too often),
you have to abandon the analysis, and "dig in".

My guess is that this problem is related to the power-supply voltages for
the video driver circuits. Second guess would be a bad video driver. (I
don't know whether it's a board or a single chip in this unit.)

On May 4, 12:57*pm, "William Sommerwerck"
wrote:
So I tried various techniques to try reproducing the problem today,
all to no avail.
I don't mean to be overly critical, but I think I see a problem. You
remind me of something I had to deal with when training technicians
in a past life. I referred to it as "Circle the wagons. The Indians are
attacking". This was in reference to the tendency for some techs to
march around the problem area, gain a little more insight, but burn
huge amounts of time going literally in circles. The Indians never
had a chance, after tiring their horses, by going in circles around
the wagons. Both you and the attacking Indians would be far more
effective with a direct assault on the problem. At some point, you
will need to dive into the LCD monitor and get your hands dirty. No
amount of additional insight or diagnostics are going to prevent this
from happening. Even if you isolate the problem to a single capacitor
and totally undestand the failure mechanism, you'll still need to
crack the case and do the necessary parts replacement. Might
as well get it over with now (before your horse gets tired).
http://www.ccl-la.com/blog/index.php...ng-214t-repair

Excellent points, that need to be repeated often.

They're related to the issue of whether you're trying to figure out exactly
what's wrong, or simply getting the unit working again. Often (too often),
you have to abandon the analysis, and "dig in".

My guess is that this problem is related to the power-supply voltages for
the video driver circuits. Second guess would be a bad video driver. (I
don't know whether it's a board or a single chip in this unit.)

Yes, I understand your point.

I think I'm more apt to approach this cautiously for several reasons.

One is that I don't have an urgent need to address the problem. This
is partly due to my other monitor working fine, and also because the
monitor does not malfunction frequently or for extended periods of
time (a couple hours of downtime over several weeks).

Another reason is that I'm not very knowledgeable or experienced on
this type of problem, so I'm ramping up quite a bit.

Yet another reason is that I'm a big proponent of measure twice, cut
once. From what I've read, opening the case isn't simple, and will
likely lead to blemishes. So I'd prefer to minimize the number of
times I have to open it, which can be accomplished by having some
confidence in the problem & solution. I understand that I won't know
or understand every detail. But I don't think knowledge will hurt,
and I'm not in a rush.

So given this list, I find it reasonable to perform some extra
diligence and learn a lot that I don't know, before digging in. I
realize some people have suggested that the caps are a common problem
w/ this monitor, but their problem doesn't seem to be the same as
mine. And I'd prefer to avoid unnecessary de-soldering & soldering,
given that I can actually make things worse. Given the symptoms of
the problem and all that I've learned from this group and the web, I'm
inclined to think the problem is the video board. But since I need to
open the case to get the video board's part & rev numbers, I'll have a
chance to inspect the caps before proceeding.

Thanks to everyone for your help, I really appreciate it. I'll post
back w/ my progress.

On May 4, 9:44*pm, saber850 wrote:
On May 4, 12:57*pm, "William Sommerwerck"
wrote:



So I tried various techniques to try reproducing the problem today,
all to no avail.
I don't mean to be overly critical, but I think I see a problem. You
remind me of something I had to deal with when training technicians
in a past life. I referred to it as "Circle the wagons. The Indians are
attacking". This was in reference to the tendency for some techs to
march around the problem area, gain a little more insight, but burn
huge amounts of time going literally in circles. The Indians never
had a chance, after tiring their horses, by going in circles around
the wagons. Both you and the attacking Indians would be far more
effective with a direct assault on the problem. At some point, you
will need to dive into the LCD monitor and get your hands dirty. No
amount of additional insight or diagnostics are going to prevent this
from happening. Even if you isolate the problem to a single capacitor
and totally undestand the failure mechanism, you'll still need to
crack the case and do the necessary parts replacement. Might
as well get it over with now (before your horse gets tired).
http://www.ccl-la.com/blog/index.php...ng-214t-repair

Excellent points, that need to be repeated often.

They're related to the issue of whether you're trying to figure out exactly
what's wrong, or simply getting the unit working again. Often (too often),
you have to abandon the analysis, and "dig in".

My guess is that this problem is related to the power-supply voltages for
the video driver circuits. Second guess would be a bad video driver. (I
don't know whether it's a board or a single chip in this unit.)

Yes, I understand your point.

I think I'm more apt to approach this cautiously for several reasons.

One is that I don't have an urgent need to address the problem. *This
is partly due to my other monitor working fine, and also because the
monitor does not malfunction frequently or for extended periods of
time (a couple hours of downtime over several weeks).

Another reason is that I'm not very knowledgeable or experienced on
this type of problem, so I'm ramping up quite a bit.

Yet another reason is that I'm a big proponent of measure twice, cut
once. *From what I've read, opening the case isn't simple, and will
likely lead to blemishes. *So I'd prefer to minimize the number of
times I have to open it, which can be accomplished by having some
confidence in the problem & solution. *I understand that I won't know
or understand every detail. *But I don't think knowledge will hurt,
and I'm not in a rush.

So given this list, I find it reasonable to perform some extra
diligence and learn a lot that I don't know, before digging in. *I
realize some people have suggested that the caps are a common problem
w/ this monitor, but their problem doesn't seem to be the same as
mine. *And I'd prefer to avoid unnecessary de-soldering & soldering,
given that I can actually make things worse. *Given the symptoms of
the problem and all that I've learned from this group and the web, I'm
inclined to think the problem is the video board. *But since I need to
open the case to get the video board's part & rev numbers, I'll have a
chance to inspect the caps before proceeding.

Thanks to everyone for your help, I really appreciate it. *I'll post
back w/ my progress.

I opened the case and analyzed all the caps--none are bulging or
leaking/oozing.

On Tue, 4 May 2010 20:15:46 -0700 (PDT), saber850
wrote:

http://www.ccl-la.com/blog/index.php...ng-214t-repair

I opened the case and analyzed all the caps--none are bulging or
leaking/oozing.

One small step... etc.

Look at the photos in:
http://www.ccl-la.com/blog/index.php/samsung-214t-repair
Do you see any bulging or leaks? Nope. Not all caps fail with
obvious physical evidence. That's where the ESR meter is used. You
can test the capacitors without removing them from the circuit.
Lacking that, just get some replacement caps, replace everything
listed in the article, and it should be back to working.

As for a better understanding of what's happening, it's difficult
enough to analyzer a circuit when all the parts are within normal
design limits. However, if you want to see what happens when you
insert a defective capacitor into the circuit, download a free copy of
LTSpice (formerly known as SwitcherCAD),
http://www.linear.com/designtools/software/
and buy a collection of SPICE switcher models:
http://pagesperso-orange.fr/cbasso/Spice.htm
http://pagesperso-orange.fr/cbasso/Downloads/LTSpice/PWM%20Switch%20LTSpice.zip
The author suggests you need the book to understand the models. I
agree.

Get the program working with a proper switching power supply. It
doesn't have to be exactly the same as the Samsung monitor. Then cram
in the equivalent of a bad capacitor, which would be a normal
capacitor, with the same capacitance value as on the label, but with
an added series resistance equal to about 2-5 times maximum ESR.
http://members.ozemail.com.au/~bobpar/2003esrchart.txt
http://members.ozemail.com.au/~bobpar/graph1.gif
http://members.ozemail.com.au/~bobpar/graph2.gif
http://members.ozemail.com.au/~bobpar/graph3.gif

A subtle hint is that with a switching power supply, the output
voltage almost never goes up when a component fails. It either goes
down, or massive amounts of high frequency ripple appears on the
output. How the rest of the LCD monitor responds to this is a bit of
a guess. Usually, it just shuts down, resulting in a black display.

Also, I forgot to caution you to *NOT* constantly power cycle the
monitor in an attempt to revive the circuit. It's bad enough having
the capacitors blow up. There's a chance that the associated
switching transistors will not appreciate the added load (which is
what's heating the capacitors) and blow up. For example, this loser
of a Dell monitor:
http://www.ccl-la.com/blog/index.php/dell-e173fpb-17lcd-repair/
usually takes out 6 xsistors, a diode, and anywhere between one and
eight electrolytics. I once tried to fix one, and didn't catch one of
the caps. Within a week, all 6 transistors were again blown.

Also, if you read the above instructions carefully, note that it
mentions resoldering the xformer leads. I do this whether it needs it
or not. What happens is that the xformers operate at about 40KHz(?).
Some of this 40KHz energy is transfered to the xformer leads,
resulting in cracked solder. It's very difficult to see without a
microscope. It was a problem with Tin-Lead solder but is really a
PITA with brittle ROHS Tin-Silver solder. The same thing can happen
at audio frequencies:
http://www.clarkeaudio.com/nfinfo.htm

Anyway, your next ordeal will be selecting the proper replacement
capacitors from the Digikey or Mouser online order pages. It's very
easy to pick the wrong part. Be careful, or ask for help. Also, buy
some spares. My prediction is that your matching monitor will soon
have the same problem.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On May 5, 12:12*am, Jeff Liebermann wrote:
On Tue, 4 May 2010 20:15:46 -0700 (PDT), saber850
wrote:

http://www.ccl-la.com/blog/index.php...ng-214t-repair
I opened the case and analyzed all the caps--none are bulging or
leaking/oozing.

One small step... etc.

Look at the photos in:
http://www.ccl-la.com/blog/index.php/samsung-214t-repair
Do you see any bulging or leaks? *Nope. *Not all caps fail with
obvious physical evidence. *That's where the ESR meter is used. *You
can test the capacitors without removing them from the circuit.
Lacking that, just get some replacement caps, replace everything
listed in the article, and it should be back to working.

As for a better understanding of what's happening, it's difficult
enough to analyzer a circuit when all the parts are within normal
design limits. *However, if you want to see what happens when you
insert a defective capacitor into the circuit, download a free copy of
LTSpice (formerly known as SwitcherCAD),
http://www.linear.com/designtools/software/
and buy a collection of SPICE switcher models:
http://pagesperso-orange.fr/cbasso/Spice.htm
http://pagesperso-orange.fr/cbasso/Downloads/LTSpice/PWM%20Switch%20L...
The author suggests you need the book to understand the models. *I
agree.

Get the program working with a proper switching power supply. *It
doesn't have to be exactly the same as the Samsung monitor. *Then cram
in the equivalent of a bad capacitor, which would be a normal
capacitor, with the same capacitance value as on the label, but with
an added series resistance equal to about 2-5 times maximum ESR.
http://members.ozemail.com.au/~bobpar/2003esrchart.txt
http://members.ozemail.com.au/~bobpar/graph1.gif
http://members.ozemail.com.au/~bobpar/graph2.gif
http://members.ozemail.com.au/~bobpar/graph3.gif

A subtle hint is that with a switching power supply, the output
voltage almost never goes up when a component fails. *It either goes
down, or massive amounts of high frequency ripple appears on the
output. *How the rest of the LCD monitor responds to this is a bit of
a guess. *Usually, it just shuts down, resulting in a black display.

Also, I forgot to caution you to *NOT* constantly power cycle the
monitor in an attempt to revive the circuit. *It's bad enough having
the capacitors blow up. *There's a chance that the associated
switching transistors will not appreciate the added load (which is
what's heating the capacitors) and blow up. *For example, this loser
of a Dell monitor:
http://www.ccl-la.com/blog/index.php/dell-e173fpb-17lcd-repair/
usually takes out 6 xsistors, a diode, and anywhere between one and
eight electrolytics. *I once tried to fix one, and didn't catch one of
the caps. *Within a week, all 6 transistors were again blown.

Also, if you read the above instructions carefully, note that it
mentions resoldering the xformer leads. *I do this whether it needs it
or not. *What happens is that the xformers operate at about 40KHz(?).
Some of this 40KHz energy is transfered to the xformer leads,
resulting in cracked solder. *It's very difficult to see without a
microscope. *It was a problem with Tin-Lead solder but is really a
PITA with brittle ROHS Tin-Silver solder. *The same thing can happen
at audio frequencies:
http://www.clarkeaudio.com/nfinfo.htm

Anyway, your next ordeal will be selecting the proper replacement
capacitors from the Digikey or Mouser online order pages. *It's very
easy to pick the wrong part. *Be careful, or ask for help. *Also, buy
some spares. *My prediction is that your matching monitor will soon
have the same problem.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Thanks. Is there a particular brand of caps which is considered the
best? From my reading, I should stay away from CapXon (which is what
the Samsung monitor uses).

On Thu, 6 May 2010 17:18:36 -0700 (PDT), saber850
wrote:

Thanks. Is there a particular brand of caps which is considered the
best? From my reading, I should stay away from CapXon (which is what
the Samsung monitor uses).

Looking at my inventory, I've been using Panasonic-ECG, type A, Series
NHG, with 105C temperature ratings. For example, the Digikey part
number for 1000UF/16v is P5533-ND
http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000CE26.pdf
http://dkc3.digikey.com/PDF/US2010/P1643.pdf

If you want to avoid the problem entirely, search for Polymer
Capacitors, which don't have any electrolyte. Fujitsu, UCC, and Oscon
make those.
http://www.fpcap.jp/en/products/index.html

I just tried to fix a Samsung Syncmaster 192N monitor. I replaced 6
assorted CapXon electrolytics but the monitor doesn't work. My ESR
meter is at home so I'll drag the pile home and report on the measured
ESR values. A bit of Googling seems to indicate the CapXon are junk.

Mo
http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On Thu, 06 May 2010 21:25:00 -0700, Jeff Liebermann
wrote:

I just tried to fix a Samsung Syncmaster 192N monitor. I replaced 6
assorted CapXon electrolytics but the monitor doesn't work. My ESR
meter is at home so I'll drag the pile home and report on the measured
ESR values.

Hmmm... Weird and not according to my guesswork, as usual.

Value Max ESR Measured ESR
1000uF 25v 0.10 0.08
1000uF 25v 0.10 0.07
1000uF 10v 0.10 0.12
1000uF 10v 0.10 0.08
330uF 25v 0.30 0.10
330uF 25v 0.30 0.10

Max ESR from this chart:
http://members.ozemail.com.au/~bobpar/2003esrchart.txt

Out of 6 caps removed and tested, only one of them is somewhat bad. No
wonder replacing the caps didn't fix the monitor. Something else is
wrong. So much for the easy fix.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Hi, i'm new here and sorry 4 my poor english, first of all this long flame seems to me much
out of site (? exagerate..?), too much word maybe for a very simple problem, i'm not a tech
but from the first agree with talks of J.Liebermann, the strange thing i spect from somone that
suspected the main 5v line that ususally supply the graphic/video chip, so is not (for me) a bad
idea to test the 5v line on the psu connector to the v.board since you don't found any bulged/
dirt capacitor, and if you find the v changes according to the fades then go to order caps, if not
try at least to measure on the regulator on v.board to see if exit 3,3v fixed or some like it.
I don't agree to what said, it's a luck that you have 2 equal monitor so in the last if you don't
find culprit you can swap boards and see

bye bye.

but from the first agree with talks of J.Liebermann, the strange thing i spect from somone that

sorry, i espected... i've made a jam.. the strange thing was: nobody has told to test 5v line..

suspected the main 5v line that ususally supply the graphic/video chip, so is not (for me) a bad
idea to test the 5v line on the psu connector to the v.board since you don't found any bulged/

On May 7, 9:06*pm, "Dav.p." wrote:
Hi, i'm new here and sorry 4 my poor english, first of all this long flame seems to me much
out of site (? exagerate..?), too much word maybe for a very simple problem, i'm not a tech
but from the first agree with talks of *J.Liebermann, the strange thing i spect from somone that
suspected the main 5v line that ususally supply the graphic/video chip, so is not (for me) a bad
idea to test the 5v line on the psu connector to the v.board since you don't found any bulged/
dirt capacitor, and if you find the v changes according to the fades then go to order caps, if not
try at least to measure on the regulator on v.board to see if exit 3,3v fixed or some like it.
I don't agree to what said, it's a luck that you have 2 equal monitor so in the last if you don't
find culprit you can swap boards and see

bye bye.

Yes, I've been considering swapping one of the boards between the
monitors. This seems like the easiest way to narrow down the problem.

is also the last way, control first out voltages, if bad change caps

On May 9, 11:12*am, saber850 wrote:
On May 7, 9:06*pm, "Dav.p." wrote:

Hi, i'm new here and sorry 4 my poor english, first of all this long flame seems to me much
out of site (? exagerate..?), too much word maybe for a very simple problem, i'm not a tech
but from the first agree with talks of *J.Liebermann, the strange thing i spect from somone that
suspected the main 5v line that ususally supply the graphic/video chip, so is not (for me) a bad
idea to test the 5v line on the psu connector to the v.board since you don't found any bulged/
dirt capacitor, and if you find the v changes according to the fades then go to order caps, if not
try at least to measure on the regulator on v.board to see if exit 3,3v fixed or some like it.
I don't agree to what said, it's a luck that you have 2 equal monitor so in the last if you don't
find culprit you can swap boards and see

bye bye.

Yes, I've been considering swapping one of the boards between the
monitors. *This seems like the easiest way to narrow down the problem.

I swapped the power boards in the monitors. The "good" monitor
immediately exhibited the problem that the previously malfunctioning
one did, while the "bad" monitor works fine (at least, so far). So
I'm confident that the problem is from the power board, and given this
thread and some web sites, I'll start w/ the caps. Now that I had
both power boards to examine, I also noticed that the C110 and C111
caps were replaced by Samsung when I sent the monitor in for repair
earlier this year (the last month of its warranty). I'll get the
specs of all caps today, find corresponding parts on DigiKey, and post
back here for confirmation.

I will research this topic on the web, but are the Polymer caps
entirely superior to electrolyte ones? Are there drawbacks to polymer
caps?

On Sun, 9 May 2010 15:04:59 -0700 (PDT), saber850
wrote:

Are the Polymer caps
entirely superior to electrolyte ones? Are there drawbacks to polymer
caps?

This article covers most everything:
http://www.capacitorlab.com/capacitor-types-polymer/
Polymer caps solve just about every complaint I can think of with
electrolytics. The major benefits are much longer lifetime, lower
ESR, and better temp stability. The down sides are the higher cost
and that they are available only in fairly low voltages.

If you can find them, and can afford the cost, do it.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

one did, while the "bad" monitor works fine (at least, so far). So

you say the bad mon. with the good power board i think...

I'm confident that the problem is from the power board, and given this

ok, 1-0 for me...
(ah it's a soccer score sorry..)

both power boards to examine, I also noticed that the C110 and C111
caps were replaced by Samsung when I sent the monitor in for repair

from what you noticed? The shining solderings?

earlier this year (the last month of its warranty). I'll get the
specs of all caps today, find corresponding parts on DigiKey, and post
back here for confirmation.

i think is not so vital to find the specs, only take uF and V and order a good brand of low esr type. (105c)

I will research this topic on the web, but are the Polymer caps
entirely superior to electrolyte ones? Are there drawbacks to polymer
caps?

As above i'm not an expert at all but i think.. with a good brand like Sanyo, Rubycon, Panasonic
etc, you can go quiet and live life in peace for at least 3-4 years intense-use,
it's a good idea replace all area's caps, to be sure.. like i said it's safer and instructive
to test the 5v line output for instability, or the 12v if 5v is stable.. but it is no so safe whitout
precautions so it's up to you, if the boards stays screwed on the back and face outside is more
safe.

On May 9, 11:00*pm, "Dav.p." wrote:
one did, while the "bad" monitor works fine (at least, so far). *So

you say the bad mon. with the good power board i think...

I'm confident that the problem is from the power board, and given this

ok, 1-0 for me... *
(ah it's a soccer score sorry..)

both power boards to examine, I also noticed that the C110 and C111
caps were replaced by Samsung when I sent the monitor in for repair

from what you noticed? The shining solderings?

earlier this year (the last month of its warranty). *I'll get the
specs of all caps today, find corresponding parts on DigiKey, and post
back here for confirmation.

i think is not so vital to find the specs, only take uF and V and order a good brand of low esr type. (105c)

I will research this topic on the web, but are the Polymer caps
entirely superior to electrolyte ones? *Are there drawbacks to polymer
caps?

As above i'm not an expert at all but i think.. with a good brand like Sanyo, Rubycon, Panasonic
etc, you can go quiet and live life in peace for at least 3-4 years intense-use,
it's a good idea replace all area's caps, to be sure.. like i said it's safer and instructive
to test the 5v line output for instability, or the 12v if 5v is stable.. but it is no so safe whitout
precautions so it's up to you, if the boards stays screwed on the back and face outside is more
safe.

Yes, I'm confident the the problem is w/ the power board, since that's
the only thing that changed, and the problem followed it. The monitor
w/ the power board from the non-malfunctioning monitor has been
functioning properly for 24 hours.

There are three reasons that I suspect the C110 and C111 caps were
replaced. The first reason is that all caps across both power boards
except those two have a hand-drawn black mark (line on the radius) on
top. Those two have slightly shinier solder. And there are small
scratches on the underside of the PCB around those caps' pins.

As for testing the 5V or 12V lines, that's not easy because the boards
are not screwed down. There is a metal plate which sandwiches these
boards to the back of the panel, and which provides the mounting
point.

On May 10, 12:46*pm, saber850 wrote:
On May 9, 11:00*pm, "Dav.p." wrote:



one did, while the "bad" monitor works fine (at least, so far). *So

you say the bad mon. with the good power board i think...

I'm confident that the problem is from the power board, and given this

ok, 1-0 for me... *
(ah it's a soccer score sorry..)

both power boards to examine, I also noticed that the C110 and C111
caps were replaced by Samsung when I sent the monitor in for repair

from what you noticed? The shining solderings?

earlier this year (the last month of its warranty). *I'll get the
specs of all caps today, find corresponding parts on DigiKey, and post
back here for confirmation.

i think is not so vital to find the specs, only take uF and V and order a good brand of low esr type. (105c)

I will research this topic on the web, but are the Polymer caps
entirely superior to electrolyte ones? *Are there drawbacks to polymer
caps?

As above i'm not an expert at all but i think.. with a good brand like Sanyo, Rubycon, Panasonic
etc, you can go quiet and live life in peace for at least 3-4 years intense-use,
it's a good idea replace all area's caps, to be sure.. like i said it's safer and instructive
to test the 5v line output for instability, or the 12v if 5v is stable... but it is no so safe whitout
precautions so it's up to you, if the boards stays screwed on the back and face outside is more
safe.

Yes, I'm confident the the problem is w/ the power board, since that's
the only thing that changed, and the problem followed it. *The monitor
w/ the power board from the non-malfunctioning monitor has been
functioning properly for 24 hours.

There are three reasons that I suspect the C110 and C111 caps were
replaced. *The first reason is that all caps across both power boards
except those two have a hand-drawn black mark (line on the radius) on
top. *Those two have slightly shinier solder. *And there are small
scratches on the underside of the PCB around those caps' pins.

As for testing the 5V or 12V lines, that's not easy because the boards
are not screwed down. *There is a metal plate which sandwiches these
boards to the back of the panel, and which provides the mounting
point.

Here's my first stab at finding replacement caps. I was not able to
find any polymer caps to replace these on Digikey or Mouser. I opted
for Panasonic if it was available.

PCB Designation Farads (µF) Voltage (V) Temp (C) Length (mm)
Potential Length (mm) Diameter (mm) Lead Spacing (Board) (mm) Mouser
Replacement Mouser Replacement URL
C105 150 450 105 41 45 20 7 661-EKMQ451VN151MP40
http://www.mouser.com/Search/Product...MQ451VN151MP40
C107 47 50 105 11 24 5 5 667-ECA-1HHG470
http://www.mouser.com/Search/Product...67-ECA-1HHG470
C301 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/Product...67-EEU-FC1E681
C302 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/Product...67-EEU-FC1E681
C110 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/Product...61R821M025EG0E
C111 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/Product...61R821M025EG0E
C112 330 25 105 14 24 10 5 667-EEU-FC1E331
http://www.mouser.com/Search/Product...67-EEU-FC1E331

If this doesn't display well, I can upload the spreadsheet as a PDF
somewhere.

On Mon, 10 May 2010 13:32:47 -0700 (PDT), saber850
wrote:

PCB Designation Farads (µF) Voltage (V) Temp (C) Length (mm)
Potential Length (mm) Diameter (mm) Lead Spacing (Board) (mm) Mouser
Replacement Mouser Replacement URL

C105 150 450 105 41 45 20 7 661-EKMQ451VN151MP40
http://www.mouser.com/Search/Product...MQ451VN151MP40

You probably do NOT need to replace the big 150uF/450V capacitor. It's
not the high voltage low ripple current capacitors that fail. It's the
low voltage, but high ripple current filter caps that get hot and blow
up.

C107 47 50 105 11 24 5 5 667-ECA-1HHG470
http://www.mouser.com/Search/Product...67-ECA-1HHG470

Tolerable. It's not a low ESR type, but it's low enough to work.

C301 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/Product...67-EEU-FC1E681
C302 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/Product...67-EEU-FC1E681

It's low-ESR (although the data sheet doesn't clearly show this) so it
will work.

C110 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/Product...61R821M025EG0E
C111 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/Product...61R821M025EG0E

Also low-ESR and good quality cap. No problems.

C112 330 25 105 14 24 10 5 667-EEU-FC1E331
http://www.mouser.com/Search/Product...67-EEU-FC1E331

Looks generally ok.

I'll leave it to you to determine if the case sizes and lead spacing
are the same as the originals. Neither is particularly critical as
there is usually plenty of room. One suggestion is to use the next
higher voltage rating capacitor. The 50v cap will probably remain
50v, but the 25v caps should be replaced with 35v caps. They last
longer, have a lower ESR, and aren't that much larger.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On May 10, 5:42*pm, Jeff Liebermann wrote:
On Mon, 10 May 2010 13:32:47 -0700 (PDT), saber850

wrote:
PCB Designation * * Farads (µF) * *Voltage (V) * * Temp (C) * * * *Length (mm)
Potential Length (mm) * * * Diameter (mm) * Lead Spacing (Board) (mm) * * * Mouser
Replacement Mouser *Replacement URL
C105 * * * *150 * * 450 * * 105 * * 41 * * *45 * * *20 * * *7 * * * 661-EKMQ451VN151MP40
http://www.mouser.com/Search/Product...51VN151MP40Svi....

You probably do NOT need to replace the big 150uF/450V capacitor. It's
not the high voltage low ripple current capacitors that fail. It's the
low voltage, but high ripple current filter caps that get hot and blow
up.

C107 * * * *47 * * *50 * * *105 * * 11 * * *24 * * *5 * * * 5 * * * 667-ECA-1HHG470
http://www.mouser.com/Search/Product...HHG470virtualk....

Tolerable. *It's not a low ESR type, but it's low enough to work.

C301 * * * *680 * * 25 * * *105 * * 17 * * *22 * * *10 * * *5 * * * 667-EEU-FC1E681
http://www.mouser.com/Search/Product...C1E681virtualk....
C302 * * * *680 * * 25 * * *105 * * 17 * * *22 * * *10 * * *5 * * * 667-EEU-FC1E681
http://www.mouser.com/Search/Product...C1E681virtualk....

It's low-ESR (although the data sheet doesn't clearly show this) so it
will work.

C110 * * * *820 * * 25 * * *105 * * 22 * * *24 * * *10 * * *5 * * * 598-361R821M025EG0E
http://www.mouser.com/Search/Product...21M025EG0Evirt....
C111 * * * *820 * * 25 * * *105 * * 22 * * *24 * * *10 * * *5 * * * 598-361R821M025EG0E
http://www.mouser.com/Search/Product...21M025EG0Evirt....

Also low-ESR and good quality cap. *No problems.

C112 * * * *330 * * 25 * * *105 * * 14 * * *24 * * *10 * * *5 * * * 667-EEU-FC1E331
http://www.mouser.com/Search/Product...C1E331virtualk....

Looks generally ok.

I'll leave it to you to determine if the case sizes and lead spacing
are the same as the originals. *Neither is particularly critical as
there is usually plenty of room. *One suggestion is to use the next
higher voltage rating capacitor. *The 50v cap will probably remain
50v, but the 25v caps should be replaced with 35v caps. *They last
longer, have a lower ESR, and aren't that much larger.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Thanks for reviewing & the feedback. I'm glad I don't need to change
the large cap.

I'm looking for a cap w/ a lower ESR for the C107 cap (47uF, 50V). I
don't see 'ESR' in the data sheet. What do I look for? Would this
one be better:
http://www.mouser.com/ProductDetail/...Hyu04R92 c%3d
?

Most of these caps were near, if not at, the physical size limit. All
of the 25V caps have = 2mm of space to a neighboring component, and
in 2 cases, it's another cap (so only one could be bigger). So there
isn't much room for these (one will actually be a very tight fit as
is).

On Mon, 10 May 2010 16:53:58 -0700 (PDT), saber850
wrote:

I'm looking for a cap w/ a lower ESR for the C107 cap (47uF, 50V). I
don't see 'ESR' in the data sheet. What do I look for?

If the ESR isn't specified, then look for loss tangent or dissipation
factor (tan sigma). Dissipation factor does NOT directly translate to
ESR, but it's proportional when comparing caps at the same frequency.
The lower number is better.
http://en.wikipedia.org/wiki/Dissipation_factor
ESR = DF / (Pi * freq * C)
You can calculate ESR, but there's a problem. The dissipation of the
dielectric varies with frequency where the ESR number specified is
only valid at the test frequency. When DF or loss tangents are
specified, it's sometimes at 120Hz, where the capacitor is intended
for a linear type AC power supply filter. When ESR is specified, it's
usually at 100KHz which implies that it's for a switching power
supply. The Panasonic EEU-FC series you included specifies ESR as
impedance at 100KHz. For comparison, a 47uF/50v Panasonic EEU-FC
series cap as below shows 0.6 ohms max ESR.

Would this
one be better:
http://www.mouser.com/ProductDetail/...Hyu04R92 c%3d

Well, for 47uf/50v the Panasonic EEU shows 0.15 DF.
The previous Chemicon KMQ series cap shows 0.12 DF.
I would call the Chemicon capacitor slightly better.

Unfortunately, the sanity check doesn't quite work. The ESR at 100KHz
grinds out to:
ESR = DF / (2Pi * freq * C)
ESR = 0.15 / (6.28 * 0.1*10^6 * 47*10^-6)
ESR = 0.15 / 29.8 = 0.0005
which is about 1000 times too small to be for real. When my brain
recovers from this cold or flu, I'll try to figure out what I've done
wrong. (I hate it when that happens).

Most of these caps were near, if not at, the physical size limit. All
of the 25V caps have = 2mm of space to a neighboring component, and
in 2 cases, it's another cap (so only one could be bigger). So there
isn't much room for these (one will actually be a very tight fit as
is).

Looking at the photos of the board, some of the caps look fairly
tight. I guess you should probably leave it at 25V.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

saber850 wrote in
:

On May 10, 5:42*pm, Jeff Liebermann wrote:
On Mon, 10 May 2010 13:32:47 -0700 (PDT), saber850

wrote:
PCB Designation * * Farads (µF) * *Voltage (V) * * Temp (C
) * * * *Length (mm)
Potential Length (mm) * * * Diameter (mm) * Lead Spacing (Board)
(mm) * * * Mouser
Replacement Mouser *Replacement URL
C105 * * * *150 * * 450 * * 105 * * 41 * * *45
* * *20 * * *7 * * * 661-EKMQ451VN151MP40
http://www.mouser.com/Search/Product...51VN151MP40Svi.
..

You probably do NOT need to replace the big 150uF/450V capacitor. It's
not the high voltage low ripple current capacitors that fail. It's the
low voltage, but high ripple current filter caps that get hot and blow
up.

C107 * * * *47 * * *50 * * *105 * * 11 * *
*24 * * *5 * * * 5 * * * 667-ECA-1HHG470
http://www.mouser.com/Search/Product...HHG470virtualk.
..

Tolerable. *It's not a low ESR type, but it's low enough to work.

C301 * * * *680 * * 25 * * *105 * * 17 * * *
22 * * *10 * * *5 * * * 667-EEU-FC1E681
http://www.mouser.com/Search/Product...C1E681virtualk.
..
C302 * * * *680 * * 25 * * *105 * * 17 * * *
22 * * *10 * * *5 * * * 667-EEU-FC1E681
http://www.mouser.com/Search/Product...C1E681virtualk.
..

It's low-ESR (although the data sheet doesn't clearly show this) so it
will work.

C110 * * * *820 * * 25 * * *105 * * 22 * * *
24 * * *10 * * *5 * * * 598-361R821M025EG0E
http://www.mouser.com/Search/Product...21M025EG0Evirt.
..
C111 * * * *820 * * 25 * * *105 * * 22 * * *
24 * * *10 * * *5 * * * 598-361R821M025EG0E
http://www.mouser.com/Search/Product...21M025EG0Evirt.
..

Also low-ESR and good quality cap. *No problems.

C112 * * * *330 * * 25 * * *105 * * 14 * * *
24 * * *10 * * *5 * * * 667-EEU-FC1E331
http://www.mouser.com/Search/Product...C1E331virtualk.
..

Looks generally ok.

I'll leave it to you to determine if the case sizes and lead spacing
are the same as the originals. *Neither is particularly critical as
there is usually plenty of room. *One suggestion is to use the next
higher voltage rating capacitor. *The 50v cap will probably remain
50v, but the 25v caps should be replaced with 35v caps. *They last
longer, have a lower ESR, and aren't that much larger.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Thanks for reviewing & the feedback. I'm glad I don't need to change
the large cap.

I'm looking for a cap w/ a lower ESR for the C107 cap (47uF, 50V). I
don't see 'ESR' in the data sheet. What do I look for? Would this
one be better:
http://www.mouser.com/ProductDetail/...?qs=sGAEpiMZZM
tZ1n0r9vR22ZOBEZetCii%252b7xHyu04R92c%3d ?

Most of these caps were near, if not at, the physical size limit. All
of the 25V caps have = 2mm of space to a neighboring component, and
in 2 cases, it's another cap (so only one could be bigger). So there
isn't much room for these (one will actually be a very tight fit as
is).


ESR Equivalent Series Resistance
http://wiki.xtronics.com/index.php/Capacitors_and_ESR
ESR is usually NOT 'important' on new capacitors.
One 'common' failure mode for electrolytic capacitors in an increase in
ESR, especially in caps that have defective designs.
http://www.badcaps.net/pages.php?vid=4



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

On May 11, 1:51*am, Jeff Liebermann wrote:
On Mon, 10 May 2010 16:53:58 -0700 (PDT), saber850

wrote:
I'm looking for a cap w/ a lower ESR for the C107 cap (47uF, 50V). *I
don't see 'ESR' in the data sheet. *What do I look for? *

If the ESR isn't specified, then look for loss tangent or dissipation
factor (tan sigma). *Dissipation factor does NOT directly translate to
ESR, but it's proportional when comparing caps at the same frequency.
The lower number is better.
http://en.wikipedia.org/wiki/Dissipation_factor
* ESR = DF / (Pi * freq * C)
You can calculate ESR, but there's a problem. *The dissipation of the
dielectric varies with frequency where the ESR number specified is
only valid at the test frequency. *When DF or loss tangents are
specified, it's sometimes at 120Hz, where the capacitor is intended
for a linear type AC power supply filter. *When ESR is specified, it's
usually at 100KHz which implies that it's for a switching power
supply. *The Panasonic EEU-FC series you included specifies ESR as
impedance at 100KHz. *For comparison, a 47uF/50v Panasonic EEU-FC
series cap as below shows 0.6 ohms max ESR.

Would this
one be better:
http://www.mouser.com/ProductDetail/...70S/?qs=sGAEpi....

Well, for 47uf/50v the Panasonic EEU shows 0.15 DF.
The previous Chemicon KMQ series cap shows 0.12 DF.
I would call the Chemicon capacitor slightly better. *

Unfortunately, the sanity check doesn't quite work. *The ESR at 100KHz
grinds out to:
* ESR = DF * / (2Pi * freq * C)
* ESR = 0.15 / (6.28 * 0.1*10^6 * 47*10^-6)
* ESR = 0.15 / 29.8 = 0.0005
which is about 1000 times too small to be for real. *When my brain
recovers from this cold or flu, I'll try to figure out what I've done
wrong. *(I hate it when that happens).

Most of these caps were near, if not at, the physical size limit. *All
of the 25V caps have = 2mm of space to a neighboring component, and
in 2 cases, it's another cap (so only one could be bigger). *So there
isn't much room for these (one will actually be a very tight fit as
is).

Looking at the photos of the board, some of the caps look fairly
tight. *I guess you should probably leave it at 25V.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Thanks for all the info.

Which tool(s) should I consider getting to help w/ the desoldering?
I'm guessing there's something to help get the solder out of the PCB
hole. Braided copper? Solder sucker?

Jeff Liebermann wrote:
wrote:
Put the hole in the tip over the exposed lead, add a bit of
solder then when it all melts, push the button on the vacuum
and move the tool in a circular motion around the pin. Turn
the vacuum off after you've removed the tool from the lead.

Circular motion? Won't that tear up the pad? If I don't get all the
solder in the first suck, I add some more solder and/or flux, get the
joint hot, and suck again. Flux is the key as you can't suck dross.
Moving the tip around the joint just seems to make a mess and more
dross.

I like to think of it as "circling the drain". Obviously
you don't press down on the pad, but I've found that doing
this circular motion makes all the difference in the world
sucking up enough solder to get an empty hole and exposed
lead.

The other Jeff.
(I haven't mailed the Symbol junk yet. Sorry.)

No rush.

Jeff


--
“Egotism is the anesthetic that dulls the pain of stupidity.”
Frank Leahy, Head coach, Notre Dame 1941-1954

http://www.stay-connect.com

Most LCD power supply boards are single sided with no plated through
holes. Those are the easiest boards to work with. When I recently

...and don't have a big ground area, for me can even work a poor 25W iron.. maybe
but depends on how big the board, to be sure start with a 50W one that
comes much useful for other works like recapping pc mainboards.. i say only to save
some money..

On May 10, 12:46*pm, saber850 wrote:
On May 9, 11:00*pm, "Dav.p." wrote:



one did, while the "bad" monitor works fine (at least, so far). *So

you say the bad mon. with the good power board i think...

I'm confident that the problem is from the power board, and given this

ok, 1-0 for me... *
(ah it's a soccer score sorry..)

both power boards to examine, I also noticed that the C110 and C111
caps were replaced by Samsung when I sent the monitor in for repair

from what you noticed? The shining solderings?

earlier this year (the last month of its warranty). *I'll get the
specs of all caps today, find corresponding parts on DigiKey, and post
back here for confirmation.

i think is not so vital to find the specs, only take uF and V and order a good brand of low esr type. (105c)

I will research this topic on the web, but are the Polymer caps
entirely superior to electrolyte ones? *Are there drawbacks to polymer
caps?

As above i'm not an expert at all but i think.. with a good brand like Sanyo, Rubycon, Panasonic
etc, you can go quiet and live life in peace for at least 3-4 years intense-use,
it's a good idea replace all area's caps, to be sure.. like i said it's safer and instructive
to test the 5v line output for instability, or the 12v if 5v is stable... but it is no so safe whitout
precautions so it's up to you, if the boards stays screwed on the back and face outside is more
safe.

Yes, I'm confident the the problem is w/ the power board, since that's
the only thing that changed, and the problem followed it. *The monitor
w/ the power board from the non-malfunctioning monitor has been
functioning properly for 24 hours.

There are three reasons that I suspect the C110 and C111 caps were
replaced. *The first reason is that all caps across both power boards
except those two have a hand-drawn black mark (line on the radius) on
top. *Those two have slightly shinier solder. *And there are small
scratches on the underside of the PCB around those caps' pins.

As for testing the 5V or 12V lines, that's not easy because the boards
are not screwed down. *There is a metal plate which sandwiches these
boards to the back of the panel, and which provides the mounting
point.

So the "working" monitor stopped working today w/ the same symptoms.
The only difference is that it has remained in this malfunctioning
state all day--the longest I've ever experienced. I can't help but
wonder if there's some truth to the theory that this is contagious.
Fortunately, I ordered 2x the caps a couple days ago. So hopefully
the problem is in fact the caps and I'll have both fixed soon.

On Thu, 13 May 2010 19:25:53 -0700 (PDT), saber850
wrote:

So the "working" monitor stopped working today w/ the same symptoms.

I warned you. Unfortunately, this one good guess does not make up for
all my other screwups.

The only difference is that it has remained in this malfunctioning
state all day--the longest I've ever experienced. I can't help but
wonder if there's some truth to the theory that this is contagious.

This is the way rumors and religions are started.

Fortunately, I ordered 2x the caps a couple days ago. So hopefully
the problem is in fact the caps and I'll have both fixed soon.

Good move by planning ahead. What else can go wrong.... Well, work on
one monitor at a time, so that you have the other board as a sample
for which way to insert the capacitors, and where the connectors and
screws are located. It should be easy (famous last assumptions).

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

In article
s.com, saber850 writes

Fortunately, I ordered 2x the caps a couple days ago. So hopefully
the problem is in fact the caps and I'll have both fixed soon.

It'd be interesting to hear how you got on.

--
(\__/)
(='.'=) Bunny's thinking about giving Windows 7
(")_(") a go despite what he's said about it...

On May 16, 8:22*am, Mike Tomlinson wrote:
In article
s.com, saber850 writes

Fortunately, I ordered 2x the caps a couple days ago. *So hopefully
the problem is in fact the caps and I'll have both fixed soon.

It'd be interesting to hear how you got on.

--
(\__/) *
(='.'=) *Bunny's thinking about giving Windows 7
(")_(") *a go despite what he's said about it...

Absolutely! I intend on posting back with my next steps.

At this point, I'm still waiting for the parts (currently expected to
arrive tomorrow). I'll say I'm not thrilled to have paid $8 to ship
a 0.4lb package which takes 5 business days to arrive. Perhaps I'm
spoiled by NewEgg's ship time & prices.

Fortunately, my monitors seem to be playing tag-team on functioning
correctly, so I can still function at this point.

On May 16, 10:42*am, wrote:
On May 16, 8:22*am, Mike Tomlinson wrote:

In article
s.com, saber850 writes

Fortunately, I ordered 2x the caps a couple days ago. *So hopefully
the problem is in fact the caps and I'll have both fixed soon.

It'd be interesting to hear how you got on.

--
(\__/) *
(='.'=) *Bunny's thinking about giving Windows 7
(")_(") *a go despite what he's said about it...

Absolutely! *I intend on posting back with my next steps.

At this point, I'm still waiting for the parts (currently expected to
arrive tomorrow). *I'll say I'm not thrilled to have paid $8 to ship
a 0.4lb package which takes 5 business days to arrive. *Perhaps I'm
spoiled by NewEgg's ship time & prices.

Fortunately, my monitors seem to be playing tag-team on functioning
correctly, so I can still function at this point.

I just completed soldering all the new caps to one of the boards! For
desoldering, I found it easier to simply heat each lead and gently
pull the cap out. The braided copper didn't really help, perhaps
because the pins are so small.

The good news is that the monitor functions fine (I thought I may have
messed up one of the caps). The unfortunate news is that only time
will tell if the problem is really solved.

I will post back with the status after a couple days. If all goes
well, I'll repeat the procedure on the other board.

Thank you all for your help thus far!

So the "working" monitor stopped working today w/ the same symptoms.
------
what do you mean for 'working', them still had power boards swapped?
A monitor can't contaminate anything, it's a stupid thought..
maybe your monitors are produced same day as them has been bopught same day
and caps are equal and fails near same month or week.

On May 21, 7:17*am, "Dav.p." wrote:
So the "working" monitor stopped working today w/ the same symptoms.
------
what do you mean for 'working', them still had power boards swapped?
A monitor can't contaminate anything, it's a stupid thought..
maybe your monitors are produced same day as them has been bopught same day
and caps are equal and fails near same month or week.

Before and after I had swapped the power boards, only one of the two
monitors worked--and it contained the same power board each time.

Yes, both monitors were bought at the same time, and used roughly
equally. But one monitor started failing over 18 months ago, while
the other just started this month.

On May 20, 10:54*pm, saber850 wrote:
On May 16, 10:42*am, wrote:



On May 16, 8:22*am, Mike Tomlinson wrote:

In article
s.com, saber850 writes

Fortunately, I ordered 2x the caps a couple days ago. *So hopefully
the problem is in fact the caps and I'll have both fixed soon.

It'd be interesting to hear how you got on.

--
(\__/) *
(='.'=) *Bunny's thinking about giving Windows 7
(")_(") *a go despite what he's said about it...

Absolutely! *I intend on posting back with my next steps.

At this point, I'm still waiting for the parts (currently expected to
arrive tomorrow). *I'll say I'm not thrilled to have paid $8 to ship
a 0.4lb package which takes 5 business days to arrive. *Perhaps I'm
spoiled by NewEgg's ship time & prices.

Fortunately, my monitors seem to be playing tag-team on functioning
correctly, so I can still function at this point.

I just completed soldering all the new caps to one of the boards! *For
desoldering, I found it easier to simply heat each lead and gently
pull the cap out. *The braided copper didn't really help, perhaps
because the pins are so small.

The good news is that the monitor functions fine (I thought I may have
messed up one of the caps). *The unfortunate news is that only time
will tell if the problem is really solved.

I will post back with the status after a couple days. *If all goes
well, I'll repeat the procedure on the other board.

Thank you all for your help thus far!

Bad news: the monitor w/ the new caps exhibited the same problem when
I first powered it on this morning. Ugh...

Yes, both monitors were bought at the same time, and used roughly
equally. But one monitor started failing over 18 months ago, while
the other just started this month.
---
OK, the contamination doesn't exists then ...
i'm sorry for your bad news.. i would to think to monitoring
the pow.supply outputs and then evaluate if is a power board problem and
which part of it, it is useful to know if want to buy an used or new board or
continue to repair . If i'm not wrong the 12v line powers the inverter that by the
video seems to work well, there is a 5v and nothing more or a 3,3v,
test them, you can also supply 5v from another p.s.u. to have a verify. If 5v is stable
there is maybe a transistor that powers the panel, it makes the on/off function
for st.by mode, i have i Benq with this failed. you can test it, or test the supply pin to the
panel, u need the datasheet of the panel for pinout, it is possible to make
a bypass of this to supply the panel like i did for test.