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Released May 23rd 2017, and is a HDR capable 4K monitor from Dell, in their UltraSharp lineup.

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Monitor won’t switch on. How to troubleshoot if PSU?

Switched on the monitor after a week away and was fine for about an hour. Heard a pop and it went black. Suspect it’s the PSU. I bought a replacement monitor since I needed to get back to work. Now that I’ve opened it up, the power supply board looks physically fine. Expect perhaps a blown cap or something. How would I go about checking if I should risk buying a replacement board off eBay etc.

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Répondre à cette question J'ai le même problème

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Eugene Khoo you can't add images in comments. Only Question or Answer. Edit your QUESTION and add images according to this guide Ajout d'images à une question existante Check the rectifiers, they love to go on the fritz as well. Anyhow, hopefully we can give you a better answer when we see.

par

I have almost the same issue with my U2718Q - Switched on the monitor after a two month away and it was fine for about half an hour. Heard a pop and it went black... But I can see burned ceramic capacitor on main board (upper right corner if inputs are at bottom, C962).

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Hi Eugene, Alvaro from Chile. I would like to know if you find the issue. I have the same monitor Dell U2718Q, and it stops working as well. I believe is a problem with the power board because there is no power light. I was using it and suddenly turned it off. Now, I want to open it up and try to resolve it on my own, but I would like to know how did it go for you.

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I opened it up and replaced 1 capacitor. Still no go.

I decided to replace the whole power board. I purchased the board from AliExpress (search for 4H.3KU01.A00) but it did not work either. I've passed the monitor on to another DIY enthusiast but at this time, he still has issues getting it to work. Neither of us knows what's the problem though. I would say your case is similar to mine.

If you decide to try to buy the powerboard, I hope it works for you. The aliexpress seller does have the other boards. ("Pretty electrical appliances Store")

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Eugen Khoo check your power fuse F601 for continuity and see if you have power on it. After that use your multimeter and check the large rectifier BD 601 and see if you have the DC and AC voltages. The " legs of the rectifier" should tell you which is AC and which is DC. Let us know what you find.

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Thanks will check that once I get my multimeter back from a friend.

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Just an update. BD601 seems to have AC and DC voltages, but F601 has no continuity. It does match my experience as I distinctly heard a pop before the monitor blacked out. Thanks for spotting those two key parts - really been a while since I opened up anything.

Just ordered a couple of those T4A 250V fuses and see if I can replace them. Haven't touched a soldering iron for over 15 years!

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Sorry - jumped the gun earlier. F601 has continuity. Tried checking BD601 again using a diode test and it does seem to pass correctly. The two center AC pins are able to pass voltage to the +ve and vice-versa if I reverse the polarity. I'm assuming it's a bridge rectifier with four diodes.

This means now that BD601 and F601 are fine. Checked a few capacitors around for continuity and resistance. C604 no continuity and reads 0.L all the time. I'm adding the photo in the question for help to ID .

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Hi Eugene, mine U2718Q is OK now after removing two fried capacitors (C962 was burn to ground and C963 looks OK but was short circuited) and replacing it with some random capacitor. It is around 14-18V at this capacitor so I take 220uf 25V and now monitor works fine for couple of days.

For conspiracy theory adepts there even a cut-out window in metal shell for easy replacement of this capacitors without tearing everything down... ;)

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Random capacitor was temporal solution but now I'm too lazy to replace it with SMD one.

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I love you man! I just did the same as you indicated and the monitor came back to life. The only thing I did differently was that the capacitor I used was 100uF / 50v and I noticed that the monitor took longer to turn on. 'I'd also like to look for SMD one, but I don't know what the indications will be. Big thanks again

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I also have dell u2718q and its not working anymore. Please let me know what could be the issue. It turns on and backlight shows up but nothing appears on screen like dell logo and anything. I was wondering if that was the case for you guys too or it's something else. What should I check. I have done physical inspection of the power supply and nothing seems to be burned. Before it died all I remember is the display brightness was some sort of blinking like in some rhythm. Let's say in 1 second it goes high and the other it gets low. It's wasn't that noticeable until one pay close attention to it and it was working just fine. And one day when I was watching YouTube it suddenly stopped displaying.

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Hello Usman. If your monitor turns on (power indicator turns white, etc.), then you most likely have a problem with the LED backlight driver. Especially if you've had some backlight issues before. Driver board is 4H.3KU33.A00 as far as I know (small board with lot of MOSFETs at the top of electronics assembly).

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Thank you so much!!! I didn't even find a capacitor to replace it but the monitor started working again after I removed the C962 and C963.

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Make sure any surge protector or power strip is correctly plugged into the outlet, and that the power switch is on. Plug in other devices to the power strip and confirm they are operating properly. Double-check that your PC's power supply on/off switch is on.

Regards,

Will

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That's what I did. It's part of a dual monitor setup so I swapped the power cables and it didn't light up either but the second monitor was again fine. Tried it a few days later with no luck either. There's no repair option from Dell so I figured that I should at least try to fix it first before sending it to a recycling center.

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Hello, my monitor is having the same issue and I came across your post when I was searching for solution. Did you continue fixing the monitor? I would be grateful if you could provide further updates if there is any, thank you.

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Eugene Khoo sera éternellement reconnaissant.
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