LCD Desktop Monitor Fading to White, then Black

S

saber850

Guest
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE


Best regards,
Nick
 
saber850 <saber850@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE


Best regards,
Nick
Click to expand...

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm
 
On May 2, 3:21 am, "N_Cook" <dive...@tcp.co.uk> wrote:
saber850 <saber...@yahoo.com> wrote in message

news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...



Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm
Click to expand...
Thanks for the quick response. I do not observe discrete jumps in the
fading--it seems very smooth to me.

I do not know if it is a backlight problem; how can I tell?
 
On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

saber850 <saber850@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE


Best regards,
Nick


Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip
Click to expand...

I don't think it is a backlight issue
My bet is a circuit problem with something common to all colors.

The brightness increases to max, then it goes negative to black. Then
it pops back to normal.

A lot of monitors have everything wrapped up in one chip.
Some ICs may drive the monitor directly.

Look for unstable supply voltage.
If the voltage is going on/off abruptly but has a big cap on the line
that would explain it.
 
On Sun, 2 May 2010 00:25:15 -0700 (PDT), saber850 <saber850@yahoo.com>
wrote:

On May 2, 3:21 am, "N_Cook" <dive...@tcp.co.uk> wrote:
saber850 <saber...@yahoo.com> wrote in message

news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...



Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm

Thanks for the quick response. I do not observe discrete jumps in the
fading--it seems very smooth to me.

I do not know if it is a backlight problem; how can I tell?
Click to expand...

A backlight gives general brightness to an image.
if it is out, the video will still be there and u can see the image if
u shine a light on the screen - effectively replacing the backlight.

your issue looks like the video is changing - not a backlight issue.

check the PS voltages first.
 
On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:

saber850 <saber850@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE


Best regards,
Nick


Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip
Click to expand...
What brand/model monitor?
What brand/model card with NVidia chip?

Does the monitor have a DSUB I/O?
Does the video card have a DSUB I/O

The symptoms don't describe an inverter problem to me
but rather an LCD matrix drive, possibley PSU derived.
 
On May 2, 6:39 am, b...@love.ranch wrote:
On Sun, 2 May 2010 00:25:15 -0700 (PDT), saber850 <saber...@yahoo.com
wrote:



On May 2, 3:21 am, "N_Cook" <dive...@tcp.co.uk> wrote:
saber850 <saber...@yahoo.com> wrote in message

news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com....

Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year..
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm

Thanks for the quick response.  I do not observe discrete jumps in the
fading--it seems very smooth to me.

I do not know if it is a backlight problem; how can I tell?

A backlight gives general brightness to an image.
if it is out, the video will still be there and u can see the image if
u shine a light on the screen - effectively replacing the backlight.

your issue looks like the video is changing - not a backlight issue.

check the PS voltages first.
Click to expand...
The problem isn't occurring at the moment. When it returns, I will
try shining a light at the screen to determine if the problem is the
backlight.

Regarding the supply voltage: both monitors (as well as the computer
itself) get their power from an APC UPS. When the problem returns, I
will try using the outlet directly on the wall.
 
On May 2, 3:05 am, saber850 <saber...@yahoo.com> wrote:
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick
Click to expand...
One thing I forgot to mention about the video is that it is not
demonstrating the typical "end" of this problem.

Typically, the monitor fades to all white, then to all black (as
captured in the video), and that's it; it will stay black. It
typically does not cycle the way it does in the video, at least not
indefinitely. It may cycle several times, but within 1 and ~5 cycles
(usually just 1 cycle), it will stay in the "black" state.
 
saber850 <saber...@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...
Hi,

My LCD desktop monitor has been exhibiting a problem
for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture,
and then
gradually fades to white, and then gradually fades to
black.

The monitor does not exhibit the problem all the time.
It comes and
goes. I do not have a procedure which triggers the
problem; it seems
to be random. Sometimes it will behave this way for
only a few
minutes, while other times it will behave like this
for weeks.

I do not do anything to trigger the problem, other
than have the
monitor powered on.

I have two of these monitors. I bought both monitors
at the same time.
Both monitors are connected to the same video card
(nVidia) via a DVI
connection. Only one of the monitors exhibits the
problem--the other
continues to function properly. When the monitor
exhibits the
problem, I can swap the DVI cables and the other
monitor continues to
function properly. So I do not believe the problem is
my video card or
computer.

I do not know of a method to get the monitor out of
this problem
state. I've tried cycling the power to the monitor,
and I've tried
rebooting the computer. Neither method fixes the
problem. The only
thing I can do is wait for it to fix itself. But
eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick
Click to expand...
Does this monitor have buttons on the front to control
brightness? Could one of those be stuck or shorted?

David
 
On May 2, 9:40 am, Meat Plow <mhyw...@yahoo.com> wrote:
On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <dive...@tcp.co.uk>wrote:



saber850 <saber...@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com....
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

What brand/model monitor?
What brand/model card with NVidia chip?

Does the monitor have a DSUB I/O?
Does the video card have a DSUB I/O

The symptoms don't describe an inverter problem to me
but rather an LCD matrix drive, possibley PSU derived.
Click to expand...
Both monitors are a Samsung SyncMaster 204B.
The video card is a ASUS EN7600GT.

The monitors have 1 DSUB I/O port and 1 VGA I/O port. I've only ever
used the DSUB I/O.
The video card has two DSUB I/O ports. Each one is connected to a
monitor.

As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors. When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly. So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Is the PSU typically isolated from other circuitry in the monitor such
that it can be replaced?
 
saber850 wrote:
On May 2, 3:21 am, "N_Cook" <dive...@tcp.co.uk> wrote:
saber850 <saber...@yahoo.com> wrote in message

news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...



Hi,
My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.
The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.
The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.
I do not do anything to trigger the problem, other than have the
monitor powered on.
I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.
I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.
A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE
Best regards,
Nick
Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm

Thanks for the quick response. I do not observe discrete jumps in the
fading--it seems very smooth to me.

I do not know if it is a backlight problem; how can I tell?
If it is the backlight, you can still see a picture in strong
Click to expand...
ambient light, try different viewing angles and light angles.
If you can still sortof see a picture, it is the backlight.
The slow fade suggests the invertor,or its powersupply circuit.
 
On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850@yahoo.com>
wrote:

On May 2, 9:40 am, Meat Plow <mhyw...@yahoo.com> wrote:
On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <dive...@tcp.co.uk>wrote:



saber850 <saber...@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

What brand/model monitor?
What brand/model card with NVidia chip?

Does the monitor have a DSUB I/O?
Does the video card have a DSUB I/O

The symptoms don't describe an inverter problem to me
but rather an LCD matrix drive, possibley PSU derived.

Both monitors are a Samsung SyncMaster 204B.
The video card is a ASUS EN7600GT.

The monitors have 1 DSUB I/O port and 1 VGA I/O port. I've only ever
used the DSUB I/O.
The video card has two DSUB I/O ports. Each one is connected to a
monitor.

As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors. When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly. So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Is the PSU typically isolated from other circuitry in the monitor such
that it can be replaced?
The problem indicates an problem with the video controller IN THE
Click to expand...
MONITOR. The Samsung 204s (and other Samsungs) have a bad reputation
for this reason. A slow fade to white can be a problem with the power
to the LCD panel itself, a fast fade to black can be caused by the
inverter. A slow fade to black MUST originate from the video
controler.

Open up the monitor, using all applicable precautions. On the video
controller should be several three terminal devices, but labeled with
a U number (as a hypothetical example, U404). Those are voltage
regulators. It is remotely possible that one of those may be putting
out an incorrect voltage. The last two digits in the part number will
be the output voltage. Again, a hyprtetical part number - L117N33B is
a 3.3 volt regulator.

PlainBill
 
On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850@yahoo.com>
wrote:

Both monitors are a Samsung SyncMaster 204B.
Click to expand...
Thank you for supplying the maker and model number.

This might be of interest:
<http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/>
<http://www.djhome.net/tips/samsungsyncmaster204T.htm>
I've seen both problems on the bench with similar Samsung models.

My usual method is to replace *ALL* the large value electrolytic
capacitors. The labour is less to do it at one time, than to spend
any time finding which one or two is the culprit. Make sure you buy
105C or 125C replacement caps as the 85c variety don't last. Larger
values and voltage ratings are fine, but watch out for package sizes
and lead spacing.

--
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
 
As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors. When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly. So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Yes, of course -- that's Troubleshooting 101.

What's going on is that the video information is being lost, and the pixel
"twist" is being forced all the way one way, then all the way the other way.
As to the cause...
 
hr(bob) hofmann@att.net wrote:

On May 2, 9:22 am, saber850 <saber...@yahoo.com> wrote:

On May 2, 9:40 am, Meat Plow <mhyw...@yahoo.com> wrote:






On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <dive...@tcp.co.uk>wrote:

saber850 <saber...@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com...

Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection. Only one of the monitors exhibits the problem--the other
continues to function properly. When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

What brand/model monitor?
What brand/model card with NVidia chip?

Does the monitor have a DSUB I/O?
Does the video card have a DSUB I/O

The symptoms don't describe an inverter problem to me
but rather an LCD matrix drive, possibley PSU derived.

Both monitors are a Samsung SyncMaster 204B.
The video card is a ASUS EN7600GT.

The monitors have 1 DSUB I/O port and 1 VGA I/O port. I've only ever
used the DSUB I/O.
The video card has two DSUB I/O ports. Each one is connected to a
monitor.

As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors. When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly. So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Is the PSU typically isolated from other circuitry in the monitor such
that it can be replaced?- Hide quoted text -

- Show quoted text -


I don't have any suggestions, but it is definitely Not the backlight.
With a fading backlight the picture would just get darker and darker,
there would be no video reversal such as shown in the video.
Are you connected to a Laptop ? is power saving kicking in an option
Click to expand...
available in your LCD if the battery is getting low?
Maybe we went over that already, I'm too tired to look back.
 
On Sun, 2 May 2010 14:14:33 -0700, "William Sommerwerck" <grizzledgeezer@comcast.net> wrote:

As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors. When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly. So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Yes, of course -- that's Troubleshooting 101.

What's going on is that the video information is being lost, and the pixel
"twist" is being forced all the way one way, then all the way the other way.
As to the cause...

I like the 'crazy LCD controller' idea -- bad connection somewhere making
Click to expand...
it cycle through the brightness range -- doesn't seem like faulty components
could make an LCD smoothly cycle brightness how you describe?

So I think the culprit is the controller PCB in the LCD, unless bad power
is provoking the thing to craziness?

Grant.
--
http://bugs.id.au/
 
On Sun, 02 May 2010 14:10:47 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:

On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850@yahoo.com
wrote:

Both monitors are a Samsung SyncMaster 204B.

Thank you for supplying the maker and model number.

This might be of interest:
http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/
http://www.djhome.net/tips/samsungsyncmaster204T.htm
I've seen both problems on the bench with similar Samsung models.

My usual method is to replace *ALL* the large value electrolytic
capacitors. The labour is less to do it at one time, than to spend
any time finding which one or two is the culprit. Make sure you buy
105C or 125C replacement caps as the 85c variety don't last. Larger
values and voltage ratings are fine, but watch out for package sizes
and lead spacing.
Click to expand...
Agree with you, there's usually room to squeeze in higher voltage caps,
and, with switching regs you could drop capacitance a little bit[1] and
not harm the circuit performance -- ripple current rating of the caps
is more important than the capacitance value of replacement cap.

[1] Got some 390/63 and 820/25 105'C low ESR caps I'd use instead of
470/35 and 1000/16 in a repair.

Grant.
--
http://bugs.id.au/
 
"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:qvprt5hb6kgboh7hs40153neg5nismmipk@4ax.com...
On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850@yahoo.com
wrote:

Both monitors are a Samsung SyncMaster 204B.

Thank you for supplying the maker and model number.

This might be of interest:
http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/
http://www.djhome.net/tips/samsungsyncmaster204T.htm
I've seen both problems on the bench with similar Samsung models.

My usual method is to replace *ALL* the large value electrolytic
capacitors. The labour is less to do it at one time, than to spend
any time finding which one or two is the culprit. Make sure you buy
105C or 125C replacement caps as the 85c variety don't last. Larger
values and voltage ratings are fine, but watch out for package sizes
and lead spacing.

--
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
Click to expand...
I was thinking capacitor too. In the old analog days one would
searching for a leaky coupling cap in the video amplifiers :)
 
On May 2, 9:22 am, saber850 <saber...@yahoo.com> wrote:
On May 2, 9:40 am, Meat Plow <mhyw...@yahoo.com> wrote:





On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <dive...@tcp.co.uk>wrote:

saber850 <saber...@yahoo.com> wrote in message
news:2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroups.com....
Hi,

My LCD desktop monitor has been exhibiting a problem for over 1 year..
It is out of warranty and I would like to fix it.

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.

The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.

I do not do anything to trigger the problem, other than have the
monitor powered on.

I have two of these monitors. I bought both monitors at the same time.
Both monitors are connected to the same video card (nVidia) via a DVI
connection.  Only one of the monitors exhibits the problem--the other
continues to function properly.  When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.

I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.

A video of the problem occurring is available here:
http://www.youtube.com/watch?v=W7YpFZVRjcE

Best regards,
Nick

Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

What brand/model monitor?
What brand/model card with NVidia chip?

Does the monitor have a DSUB I/O?
Does the video card have a DSUB I/O

The symptoms don't describe an inverter problem to me
but rather an LCD matrix drive, possibley PSU derived.

Both monitors are a Samsung SyncMaster 204B.
The video card is a ASUS EN7600GT.

The monitors have 1 DSUB I/O port and 1 VGA I/O port.  I've only ever
used the DSUB I/O.
The video card has two DSUB I/O ports.  Each one is connected to a
monitor.

As I mentioned in the OP, when the monitor is malfunctioning, I have
swapped the DVI cables between the monitors.  When doing so, the
malfunctioning monitor continues to malfunction while the other
monitor (the one which has never malfunctioned) continues to function
properly.  So from this, I believe the computer & video card are
functioning properly. Am I making a valid assessment here?

Is the PSU typically isolated from other circuitry in the monitor such
that it can be replaced?- Hide quoted text -

- Show quoted text -
Click to expand...
I don't have any suggestions, but it is definitely Not the backlight.
With a fading backlight the picture would just get darker and darker,
there would be no video reversal such as shown in the video.
 
In article <2468c376-1884-4039-af3a-55c41cedb3c6@k29g2000yqh.googlegroup
s.com>, saber850 <saber850@yahoo.com> writes

The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.
Click to expand...
Erk. That video you put on Youtube is kinda creepy! Are you sure it's
not demonic possession?

I don't think it's a backlight problem. It looks more like a contrast
issue. I have a similar Samsung monitor (SyncMaster 2343 widescreen)
with touch controls and It looks like yours has those too. In your
situation, the first thing I would do is whip the back off and
disconnect the touch control board from the main board and see if the
problem stops. I'm wondering if a "button" is stuck.

Then I'd probably move to gently heating some of the chips, particularly
those on the back of the LCD panel, with a hairdryer to see if the fault
is temperature-related.

I know you say you want to try and fix it, but if it's a panel fault,
the monitor's fit only for scrap.

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