Dell U3011 randomly powers off and back on again a few seconds later

[ssheikh]

All,

I do not have pictures yet as I have not started troubleshooting the monitor by taking it apart.

The problem is the monitor randomly appears to power itself off and then after a random delay comes back on by itself. Splashes the Dell logo on the screen and starts displaying the image again a few seconds later. During this time when its having its fit the light in the power switch goes off. Most of the time the delay to power back up is in the range of 2 ~ 10 seconds. But in a couple of instances it has stayed off for at least 2 hours at which point I just unplugged the power cord. A day later when I plugged it back in it started working again.

When the monitor shuts itself off, hitting the power switch does nothing. Also when the monitor is having its fit, the power on its USB ports and the power for the audio bar stays on.

So far I have owned 4 dell Ultrasharp monitors. This U3011 and three 2007FP. every single one of these monitors developed this exact same problem once outside the warranty. On the 2007FP the problem very rapidly got worse until one of the DC-DC converters (5V that feeds the main board) on the USB board would die. After fixing the USB board the monitor would work fine for a couple of months, would develop the same problem again and would die again. In my last attempt to fix them, I repaired the USB board and also replaced the main board from monitors with busted screens and all three of the 2007FPs have been running fine for the last 6 months (except one has a problem that it never goes into power save mode - a problem that it inherited from the donor monitor.)

On this U3011, the problem is not getting worse or if it is its at such a slow pace that it is not noticeable. Problem is certainly worse when the ambient temperature is high but it still does happen even when ice cold air is being blown directly on the monitor with its back plastic cover removed.

I would like to hear from anyone that has attempted to repair this monitor or a similar one of their experience. I have taken the monitor apart a few times already so I am not looking for general tear down information. But would certainly like to hear from someone that has attempted to repair the DC-DC converters on the main board of this monitor.

And if someone happens to have the schematic, that would be awesome.

Thanks,

Shahid

[ssheikh]

Re: Dell U3011 randomly powers off and back on again a few seconds later

Quick update. The interface board on this monitor had a lot of flux residue on the underside of it. The residue appeared to be left over from (a poor?) manufacturing process. I did a thorough wash of the board with a tooth brush under a flowing stream of isopropyl. Then a 20 minute bake in a toaster oven at 85 C to evaporate any water droplets. My isopropyl was the CVS kind so it had a lot of water content in it.

The monitor has been running for 20+ hours since and has not done its on/off routine yet. Fingers crossed.

[gtsagian]

Re: Dell U3011 randomly powers off and back on again a few seconds later

Quick update. The interface board on this monitor had a lot of flux residue on the underside of it. The residue appeared to be left over from (a poor?) manufacturing process. I did a thorough wash of the board with a tooth brush under a flowing stream of isopropyl. Then a 20 minute bake in a toaster oven at 85 C to evaporate any water droplets. My isopropyl was the CVS kind so it had a lot of water content in it.

The monitor has been running for 20+ hours since and has not done its on/off routine yet. Fingers crossed.

I have the same problem, u3011 bought in 2011. Can you please verify if this fixed it? I am having trouble with it for like a month now, but I had real trouble turning it on today. It was raining yesterday, so maybe it's related to higher humidity, lower temprature or just random.

Like you, I have trouble powering it up. When the screen goes black, I leave it off for like 1 min and retry. After 2-4 times going black, it stays on for like forever. But I had real trouble this morning.

[ssheikh]

Re: Dell U3011 randomly powers off and back on again a few seconds later

3 years later, unfortunately, no I don't have it fully fixed.

Also, sounds like the symptoms you are seeing may be a little different than mine.

In the process of fixing mine, I have completely replaced the 24V power supply with a vicor dc-dc module. I have also bypassed Vdd on all the major chips on the logic/control board with good quality CK05 100nF (Kemet) capacitors.

I also have a fan in there to cool the vicor module and the rest of the system.

It lasts be through winter without a problem. As summer approaches, it starts having issues.

In my case the issue is probably not with the power supplies. I noticed that when the monitor powers back up after it dies, it goes through a full boot-up sequence by displaying the Dell logo and having the blue LEDs ramp up and back down as if someone had just plugged in the power to it. What I am suspecting is that the bootstrap microcontroller in there goes astray and winds up resetting.

That microcontroller probably stays powered up all the time since its powered by 5V standby bus. If I cut the power to it by disconnecting the mains power and leave it disconnected for a few hours, I can get the monitor to run for longer before it starts having issues.

To minimize the issue, I have the monitor plugged into a motion sensed power strip. So when I am not in my office, the power strip completely cuts off power to it. That way when I start using it, it lasts me 3 ~ 4 hours before starting to have the fits of powering off and back on again.

In the end, I have spent a lot of time and more money than the monitor is worth. The overall design in there is marginal and it certainly not made with longitivity in mind.

My advice to anyone that hasn't been able to fix their Dell monitor by simply replacing failing power supply capacitors is to just dump it and buy a new one. Not worth the hassle trying to fix them if the problem is more complicated.

[helob]

Re: Dell U3011 randomly powers off and back on again a few seconds later

I have a Dell U3011 which exhibited blank dark screen but touch buttons are still working as red power light still show.
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.