Dell U3011 no display after a few minutes

[darran]

Re: Dell U3011 no display after a few minutes

It was quite a shocker if you know what I mean ;P I don't think I have the test tools that you all do so I'm going to take a different approach and swap out the parts from another monitor until I find out which one is broken. Then I will try to find out what is broken on that part.

Thank you all!

[Davi.p]

Re: Dell U3011 no display after a few minutes

I don't like when users here makes confusion with their's issues and inquinate some other's post, let's try to remain on the O.P. sympthoms. As always is not bad to take out the PSU and test it with dummy loads, even if i don't think it is the problem.. also one can stimolate an heat related behavior by sourcing some hot hair to the boards, starting from the t-con, ending on main b'd, triyng to locate always more precisely the area of failure. No one has said if when screen goes blank you see a backlight lit. It is possible that an unconsistent short on a mosfet or ic on tcon or main let go in to protection the psu shutting down also backlight.

[budm]

Re: Dell U3011 no display after a few minutes

At least plug the DUT into a GFCI outlets.

[CapLeaker]

Re: Dell U3011 no display after a few minutes

I bet that the primary doesn't feel good.

[darran]

Re: Dell U3011 no display after a few minutes

Be careful while it's plugged in. I just shocked myself pretty good!

[darran]

Re: Dell U3011 no display after a few minutes

It could be. I'll check the solder joints. It would come back to life when I would shake it while it was fully disassembled. I put it partially back together so I cold use the stand with it and now shaking it does not bring it back to life.

Here are some pictures that show the disassembly process.

Lay the monitor on a flat surface on it's face. Make sure nothing is under it so that the screen is not damaged:

https://goo.gl/photos/Gkq3V24VThMG1S2JA

Remove the stand ( I needed a star shaped screwdriver. I used a screwdriver from an iPhone disassembly kit purchased from ifixit. This can be seen to the left of the picture below):

https://goo.gl/photos/tS9nwbEqnzVEFrGu9

Now we need to remove the bezel. We do this with our fingers by reaching inside the the inner part of the bezel and pulling upward. Please start this process away from the buttons. The buttons must be considered so that the ribbon is not damaged.

https://goo.gl/photos/M4zLg6TRqkuWMEAr8

This shows what it will look like when the bezel lifts up:

https://goo.gl/photos/9uyZ2sdYx19ubeV99

Work your away around the bezel towards the buttons. When you get there please be careful. There is a ribbon that connects the buttons to the mainboard that wraps around the back of the panel. Carefully remove this part and lay the bezel still connected to the ribbon next to the monitor:

https://goo.gl/photos/iJXTBixdwuN95LPA7

https://goo.gl/photos/KNAixnqaZhYmynSG9

https://goo.gl/photos/bVsnrgVpzjsb3z9b8

Now we need to take the cover off of what I believe is the inverter board. This requires a philips head screwdriver. A screwdriver that has a longer shaft will be better in these tight areas. Remove the panel.

https://goo.gl/photos/cs3yJwuBcEzrdJ8A7

https://goo.gl/photos/acNLydxR3zWTDPHN8

Once that is complete, remove the unit that houses the side usb ports. Next begin removing the panel that covers the main board. Be very careful to not damage the ribbon that connects to the buttons on the front panel!

https://goo.gl/photos/YCeAMcecFX3fhNeF7

https://goo.gl/photos/fY8jmJCDqjLhmYRs6

The ribbon can be removed by pushing this clip like plastic that is on the board. You push the release outwards towards the ribbon. Once it is snapped out then you can safely remove the ribbon.

https://goo.gl/photos/WJMuoPbdTpJiH21e6

Now you should have full access to the main board.

https://goo.gl/photos/RXf1jx55L1sjhsD49

There was white plastic like things on top of the main board. I'm not sure what they are for, but I left them there.

Thank you!

[CapLeaker]

Re: Dell U3011 no display after a few minutes

With a DMM measure the resistance of the output winding on each transformer and compare them to each other. IF there is more than 3% difference, it's bad.
Since the monitor comes back on when you shake it, it sounds more like some cold solder joint or a bad connector?

[darran]

Re: Dell U3011 no display after a few minutes

How do I test the inverters?

[CapLeaker]

Re: Dell U3011 no display after a few minutes

The monitor has gone blank multiple times in the past 20 minutes. If I shake it, it will turn back on.

Probably something loose then? O.k. I guess it is a LCD, not a LED monitor after all. If it has multiple transformers on the inverter for the CCFL backlights, compare the output winding from one transformer to the next (with the monitor unplugged off course). If they are more than 3% from each other, they are bad. Also could be the connector on the CCFL.

[darran]

Re: Dell U3011 no display after a few minutes

How do I locate the power supply board? How do I check the power output of it?

[mooreaa]

Re: Dell U3011 no display after a few minutes

I'm having similar issues on mine, not trying to hijack your thread but have you measured the 24V output from the power supply board? I noticed on mine that when the display goes black, the 24V output from the power supply board (PS-2201-3-HF mines a REV A) tanks to 0V. Turn off the display for a while, turn it back on, display turns on and the 24V is fine ... for a few a while.

[darran]

Re: Dell U3011 no display after a few minutes

The monitor has gone blank multiple times in the past 20 minutes. If I shake it, it will turn back on.

[darran]

Re: Dell U3011 no display after a few minutes

To answer the previous posters question I did not notice any picture when the display is black.

[Topcat]

Re: Dell U3011 no display after a few minutes

an backlight LED going bad.

Just an FYI, the u3011 is not LED, its CCFL. The first 30" LED from dell was the u3014.

[darran]

Re: Dell U3011 no display after a few minutes

This is what the board looks. I looked at the caps and didn't notice anything out of place. The board does make kind of like a high frequency hum when the monitor is on, but does not have input.

I don't have really any tools that are specific to troubleshooting electronics, but can probably get access to some if I know what I need.

Thank you for all of the help. I will post steps on how to dismantle with pictures shortly.

[helob]

Re: Dell U3011 no display after a few minutes

darran & X5-452,
I also have a Dell U3011 which displayed the same problem.
I find it difficult to open/dismantle the unit as there is no screw or sloth to prick open to take a look inside.
Would appreciate if you can share your experience in open/dismantle the unit.
Thank you and have a nice day.

[darran]

Re: Dell U3011 no display after a few minutes

Will do. Thank you so much for the help!

[CapLeaker]

Re: Dell U3011 no display after a few minutes

Maybe upload some high resolution straight shot pictures of your PSU and mainboard.

[darran]

Re: Dell U3011 no display after a few minutes

I am having a similar issue. My monitor will turn on and work perfectly, but then turn itself off after a few minutes. The blue buttons are still lit up, but they do not display the configuration menu on the screen when pressed.

If i turn off the monitor and unplug it and plug it back in it will start working again. Sometimes for hours.

Does anyone know what I can do to fix this? I have remove the LCD unit from the case, but have not fully disassembled it yet.

I am looking for a multimeter to check power output.

Thank you!

[CapLeaker]

Re: Dell U3011 no display after a few minutes

an backlight LED going bad.