Screen completely grey but now image

[Dutchier]

I have a Dell 2208WFPt which is showing a completely grey screen.
The status LED is showing green as if a video signal is connected, but it's not.
When I play with the control buttons a bit it goes black and the status LED goes orange as if no signal is connected.

The OSD menu is also not showing up anywhere.

Just found 'A guide on how to troubleshoot 2 seconds to black' and will try this too except the tests with power on.

I'm also trying to get a working 2208WFPt from the office to temporary swap parts for testing

I couldn't find much on grey screen issues on the web.
What would be the most likely cause?
Short circuit in the video processing board or the power supply board?

I opened up the screen to see if there were any burn marks or leaking fluids but it's completely clean.
Very interested to hear if bad caps could be causing this even when the caps look fine from the outside!

[budm]

Re: Screen completely grey but now image

It can be due to the T-CON board on the LCD panel is not getting the 5v/12v from the main board or the surfaced mounted fuse on the T-CON board has failed, or other regulator/switching power supply on the T-CON has failed.
Does it glow like this?
http://s807.photobucket.com/albums/y...t=DSCF1912.jpg
http://s807.photobucket.com/albums/y...t=DSCF0881.jpg

Dell:
http://s807.photobucket.com/albums/yy352/budm/DELL/

[selldoor]

Re: Screen completely grey but now image

Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

It will be useful if you can say a bit about yourself - skills tools etc.
Do you have a Multimeter and soldering equipment.

First thing to try might be to unplug and reseat all cables/connectors.

[Dutchier]

Re: Screen completely grey but now image

[QUOTE=budm;280217]
Does it glow like this?
http://s807.photobucket.com/albums/y...t=DSCF1912.jpg

It glows exactly like that!
What was the cause there?

I spilled water over my laptop (p.s. I normally don't wreck hardware every day) so currently fixing this first before fixing the monitor
Will continue this weekend!

[budm]

Re: Screen completely grey but now image

It may have lost the the surface mounted fuse on the T-CON oard on the LCD panel assembly, or the cable between the T-CON and the main /logic board may have come loose, or the main/logic board does not supply the power to the T-CON.
Post the pictures so we can see how this monitor is setup.

[Dutchier]

Re: Screen completely grey but now image

I've just swapped the power and controller board from a working monitor and the image is still grey.
The boards from the grey screen do power on the other screen so the boards are fine.

The issue seems to be in the screen or the board which is on the screen (I believe you call this the T-CON board).

It could be that there are some resistors missing, there are some empty spaces but no loose parts inside the housing so this could be by design as there are quite a few empty spaces (R13, C6, R20C55, R37, R103, R99, R98, R94, C5 and R54)

Unfortunately the working monitor has the same power and controller boards but a different screen and T-CON board so I am unable to check if there indeed are parts missing.
The flatcables are all firmly attached.

[budm]

Re: Screen completely grey but now image

Look for very small surface mounted fuse close to the connector, it should be something like F1.
Can I see good closed up pictures around the connector?

[Dutchier]

Re: Screen completely grey but now image

Had some issues attaching large files.
Just uploaded them as rar file (sorry, large zip files not allowed :-))
The fuse looks ok. I'll go look for the multimeter, see if that can help :-D

[budm]

Re: Screen completely grey but now image

Measure the voltage at both fuse with ref to ground, it should have either 5 or 12V. The T-CON board will also two or more switching power supplies and regulators ICs also.

[selldoor]

Re: Screen completely grey but now image

I have resized the board picture - fuse is clearly visible it has a K on it.

It may be the picture but I am concerned about the section below where I have put a red line - has it been damaged - does it affect any of the ribbon
bonding.

[Dutchier]

Re: Screen completely grey but now image

The plastic cover of the T-CON board has been cut in order to access it. The ribbon bonding is intact, nothing damaged there.

I've messured the voltage before and after the fuse and I get 5,29 volt in front of it and 0 Volt after. That was a good tip!
So it this seems to be blown (although no damage is visible).

What would you recommend as next troubleshoot step? Insert a new fuse and see what happens?
Or just by-pass the fuse with a copper wire (and possible fry the rest of the parts)?
Not sure what caused the fuse to fail so my guess it to try a new fuse.
Or are there more interesting parts to measure?

P.S. I'm not really an expert on troubleshooting electronics but do know which parts of a monitor NOT to touch though

[jetadm123]

Re: Screen completely grey but now image

The fuse blew to a possible short on the board. Many times a capacitor shorts out and causes the fuse to blow. Try performing a quick resistance check across each cap. Any cap that reads 30 ohms or less will require additional testing.

[selldoor]

Re: Screen completely grey but now image

Fuse is probably 1.5 amps based on the K marking