LCD Desktop Monitor Fading to White, then Black

saber850 · May 10, 2010

On May 10, 12:46 pm, saber850 <saber...@yahoo.com> wrote:

On May 9, 11:00 pm, "Dav.p." <davi...@tiscali.it> 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 (ľF) 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/ProductDetail.aspx?R=EKMQ451VN151MP40Svirtualkey66100000virtualkey661-EKMQ451VN151MP40
C107 47 50 105 11 24 5 5 667-ECA-1HHG470
http://www.mouser.com/Search/ProductDetail.aspx?R=ECA-1HHG470virtualkey66720000virtualkey667-ECA-1HHG470
C301 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-FC1E681virtualkey66720000virtualkey667-EEU-FC1E681
C302 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-FC1E681virtualkey66720000virtualkey667-EEU-FC1E681
C110 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/ProductDetail.aspx?R=361R821M025EG0Evirtualkey59850000virtualkey598-361R821M025EG0E
C111 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/ProductDetail.aspx?R=361R821M025EG0Evirtualkey59850000virtualkey598-361R821M025EG0E
C112 330 25 105 14 24 10 5 667-EEU-FC1E331
http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-FC1E331virtualkey66720000virtualkey667-EEU-FC1E331

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

saber850 · May 11, 2010

On May 10, 5:42 pm, Jeff Liebermann <je...@cruzio.com> wrote:

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

saber...@yahoo.com> wrote:
PCB Designation Farads (ľF) 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/ProductDetail.aspx?R=EKMQ451VN151MP40Svi....

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/ProductDetail.aspx?R=ECA-1HHG470virtualk....

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/ProductDetail.aspx?R=EEU-FC1E681virtualk....
C302 680 25 105 17 22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-FC1E681virtualk....

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/ProductDetail.aspx?R=361R821M025EG0Evirt....
C111 820 25 105 22 24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/ProductDetail.aspx?R=361R821M025EG0Evirt....

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/ProductDetail.aspx?R=EEU-FC1E331virtualk....

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 je...@cruzio.com
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/Panasonic/EEU-EB1H470S/?qs=sGAEpiMZZMtZ1n0r9vR22ZOBEZetCii%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).

Jeff Liebermann · May 11, 2010

On Mon, 10 May 2010 16:53:58 -0700 (PDT), saber850
<saber850@yahoo.com> 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/Panasonic/EEU-EB1H470S/?qs=sGAEpiMZZMtZ1n0r9vR22ZOBEZetCii%252b7xHyu04R92c%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 jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

bz · May 11, 2010

saber850 <saber850@yahoo.com> wrote in
news:16a07027-3ed3-420e-ba09-9374f670316d@37g2000yqm.googlegroups.com:

On May 10, 5:42 pm, Jeff Liebermann <je...@cruzio.com> wrote:
On Mon, 10 May 2010 13:32:47 -0700 (PDT), saber850

saber...@yahoo.com> wrote:
PCB Designation Farads (ľF) 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/ProductDetail.aspx?R=EKMQ451VN151MP40Svi.
..

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/ProductDetail.aspx?R=ECA-1HHG470virtualk.
..

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/ProductDetail.aspx?R=EEU-FC1E681virtualk.
..
C302 680 25 105 17
22 10 5 667-EEU-FC1E681
http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-FC1E681virtualk.
..

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/ProductDetail.aspx?R=361R821M025EG0Evirt.
..
C111 820 25 105 22
24 10 5 598-361R821M025EG0E
http://www.mouser.com/Search/ProductDetail.aspx?R=361R821M025EG0Evirt.
..

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/ProductDetail.aspx?R=EEU-FC1E331virtualk.
..

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 je...@cruzio.com
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/Panasonic/EEU-EB1H470S/?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.

saber850 · May 11, 2010

On May 11, 1:51 am, Jeff Liebermann <je...@cruzio.com> wrote:

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

saber...@yahoo.com> 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/Panasonic/EEU-EB1H470S/?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 je...@cruzio.com
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 · May 11, 2010

On Tue, 11 May 2010 05:32:59 -0700 (PDT), saber850
<saber850@yahoo.com> wrote:

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?

Sigh. We're really down to the basics. You're probably dealing with
RoHS solder. That means an 850F tip and a temperature controlled
soldering iron. 750F will work, but takes a bit longer. I haven't
looked at cheap soldering irons for a long time, so I don't have a
specific recommendation. Note that if the soldering iron is rated
only in watts, not temperature, go find something else. It's probably
not temperature controlled.

I recently bought one of these conglomerations:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290434181031>
but haven't had a reason to use it yet. It looks big, clumsy, and has
a rather large tip, but looks useful for some things. I don't think
cleaning the pump is going to be fun while attached to a hot iron. We
shall see.

Some kind of vacuum solder sucker should work:
<http://www.parts-express.com/pe/showdetl.cfm?partnumber=370-030>
Radio Shack also carries these. Lots more on eBay. Solder braid
might also be handy, but not really necessary.

Most LCD power supply boards are single sided with no plated through
holes. Those are the easiest boards to work with. When I recently
replaced all the electrolytics on a Samsung LCD display (which didn't
fix the problem), I just heated up the leads, and pulled on the
capacitor case. No need for anything more elaborate. If the board
was double sided or multi-layer, which have plated through holes, the
solder sucker and solder wick would be needed.

If you haven't done much soldering, I suggest you practice with some
scrap boards before attacking.

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

Jeffrey D Angus · May 11, 2010

saber850 wrote:

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?

Solder suckers seem best suited for vacuum tube sockets and
terminal strips. Solder Wick(tm) Seems best suited for lifting
traces.

I've had extremely good luck using one of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320523954535

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.

Occasionally, I get a lead stuck in the hole, but a simple
chisel tip can get it free. Go back over, add solder and re-
vacuum the hole to get it empty afterwards.

The key to ANY soldering operation whether it is assembly or
desoldering is hot enough, fast and clean.

Of course, like the other Jeff I do this for a living, so
investing in the correct tools is money well spent.

Jeff

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

http://www.stay-connect.com

Jeff Liebermann · May 11, 2010

On Tue, 11 May 2010 13:18:55 -0500, Jeffrey D Angus
<jangus@suddenlink.net> wrote:

Solder suckers seem best suited for vacuum tube sockets and
terminal strips. Solder Wick(tm) Seems best suited for lifting
traces.

I just hate to agree with you, but you're right. Still, it is
possible to remove components with either device if you're careful.
However, for massive desoldering jobs, nothing beats a propane torch,
air compressor, and blow gun.

I've had extremely good luck using one of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320523954535

Retch. I suffered with one of those for about a year at a former
employer. About every 5 sucks, I had to clean the self clogging tip.
There were about 5 of them in the lab and all of them clogged exactly
the same way.

I switched to an overpriced Pace desoldering station and sucked
happily ever after.
<http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg>
Big and ugly really is better.

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.

Occasionally, I get a lead stuck in the hole, but a simple
chisel tip can get it free. Go back over, add solder and re-
vacuum the hole to get it empty afterwards.

Yep.

The key to ANY soldering operation whether it is assembly or
desoldering is hot enough, fast and clean.

Yep, yep, yep.

Of course, like the other Jeff I do this for a living, so
investing in the correct tools is money well spent.

You call this living? I'm still agonizing over buying a hot air SMT
desoldering station. I was borrowing one for a while and became
addicted.

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

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

Jeffrey D Angus · May 11, 2010

Jeff Liebermann wrote:

jangus@suddenlink.net> 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

Dav.p. · May 11, 2010

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..

Jeff Liebermann · May 14, 2010

On Thu, 13 May 2010 19:25:53 -0700 (PDT), saber850
<saber850@yahoo.com> 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 jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

saber850 · May 14, 2010

On May 10, 12:46 pm, saber850 <saber...@yahoo.com> wrote:

On May 9, 11:00 pm, "Dav.p." <davi...@tiscali.it> 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.

Mike Tomlinson · May 16, 2010

In article <6b0a157b-e045-40eb-a7a9-cee3092a7d92@h39g2000yqn.googlegroup
s.com>, saber850 <saber850@yahoo.com> 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...

May 16, 2010

On May 16, 8:22 am, Mike Tomlinson <m...@jasper.org.uk> wrote:

In article <6b0a157b-e045-40eb-a7a9-cee3092a7...@h39g2000yqn.googlegroup
s.com>, saber850 <saber...@yahoo.com> 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.

saber850 · May 21, 2010

On May 16, 10:42 am, adse...@wheeloyum.com wrote:

On May 16, 8:22 am, Mike Tomlinson <m...@jasper.org.uk> wrote:

In article <6b0a157b-e045-40eb-a7a9-cee3092a7...@h39g2000yqn.googlegroup
s.com>, saber850 <saber...@yahoo.com> 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!

Dav.p. · May 21, 2010

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.

saber850 · May 21, 2010

On May 21, 7:17 am, "Dav.p." <davi...@tiscali.it> 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.

saber850 · May 21, 2010

On May 20, 10:54 pm, saber850 <saber...@yahoo.com> wrote:

On May 16, 10:42 am, adse...@wheeloyum.com wrote:

On May 16, 8:22 am, Mike Tomlinson <m...@jasper.org.uk> wrote:

In article <6b0a157b-e045-40eb-a7a9-cee3092a7...@h39g2000yqn.googlegroup
s.com>, saber850 <saber...@yahoo.com> 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...

Dav.p. · May 21, 2010

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.

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