Dell U2410f

[wasmundt]

Symptoms are that the LED lights will turn on and I can get the buttons to beep at me as if I'm modifying settings, but I get no display whatsoever. I attached images of the power board as well as the display board. None of the capacitors appear to have corrosion on them.. I haven't replaced anything as of right now. Just wondering if any of you here had any ideas on where to go/start at. Thanks in advance!

Let me know if you need any further information.

Sam

[killian6pk]

Re: Dell U2410f

Start making a list of the black caps on your power board. Make the list by the Cxxx located next to each cap. The C = Capacitor and the xxx is the numbered location on the board. You need the following information. UF rating, Voltage rating, Manufacturer ID number, Diameter in millimeters and height in millimeters. Do not bother with the Large Cap laying on its side. Looks like one of the smaller caps is a brown color get that one also. The small silver caps I am not sure if those need replacing. After you make the list report back here and list them. You will get help in where to go to find replacements. You will probably need to replace all of those caps on your list. They will be cheap enough probably less than $10.00 including shipping. That is if you live in the U.S. Also while you are waiting for info do a search for this model number and see if anyone has had problems before. Read everything written it should shortcut your learning time.

[wasmundt]

Re: Dell U2410f

Was just about to go ahead and order a capacitor kit from eBay and try swapping out the capacitors. My concern is that I don't feel that any of them are ballooning up, but I haven't verified electrically if they are still working - it will probably be easier to just go ahead and swap them out.

Hypothetically speaking, if I do the replacement and nothing changes what would your guys suggestion be at that point.

Thanks,
Sam

[tom66]

Re: Dell U2410f

First suggestion would be to avoid eBay for capacitors unless you absolutely have to. Lots of sellers miss out important big or small caps, and it often costs more than an equivalent order with a supplier such as DigiKey. Also they often use inferior (non-low ESR, or known bad) capacitors.

DigiKey is $2-3 shipping in US, caps are typically around 20 cents to 50 cents each.

Panasonic FR, FM, FC, in order of "excellent" to "very good", are often suggested around here, as replacement capacitors.

[Kiriakos GR]

Re: Dell U2410f

Those screens has three years warranty.

Why to repair it by your own ?

[Lumberjack777]

Re: Dell U2410f

Can you see an image on the screen when you shine a flashlight into it? I use a dark room and shine the flashlight from many different angles to check.

Also, you are going to need a digital multimeter. There's no way you can diagnose this monitor without one. ~L-J-7~

[wasmundt]

Re: Dell U2410f

Lumberjack777 - thanks for the suggestion!!! When I place a flashlight immediately against the area where the menu bar should be and I press any of the buttons there, the menu does indeed display.

Any good pointers to research up on to try and fix the problem? Or is this something I should just toss? I don't mind tinkering around as I find it fun and I have an EE degree, so am somewhat grounded in the theory.

As to sending it back, it's outside of the three year period - nor am I the original owner.

Thanks!
Sam

[budm]

Re: Dell U2410f

Do you have good clear pictures of both sides of the power supply board?
I may be:
Bad power supply for backlights circuit.
Bad Backlights circuit
No Backlights on signal from main board.

[Lumberjack777]

Re: Dell U2410f

Do you have good clear pictures of both sides of the power supply board?
I may be:
Bad power supply for backlights circuit.
Bad Backlights circuit
No Backlights on signal from main board.

Good idea Bud. Maybe I'm confused but I don't see the inverter in any of those pics. If you can see an image with a flashlight, then the most likely culprit is the inverter board, or a bad CCFL. Can you get us front and back pictures of the inverter board? Thanks. ~L-J-7~

[wasmundt]

Re: Dell U2410f

ok - here's an update, I went to radio shack and bought 4 replacement capacitors. (probably not the best quality, but didn't really want to wait and if it solved the problem then I could upgrade them at a later point and be happy with everything ) That being said, the issue persists.

I could have messed something up when soldering them.. but I don't think I did. I've attached some pictures below of the solder job, as well as some more pictures of the power board and the inverter.

This monitor doesn't look to have a single CCFL but instead multiple smaller ones that are connected across the inverter. When you see the picture you should be able to gather what I'm saying. **Edit** The backlight style is known as a "7 CCFL U-type system".

I took some measurements off the power connector going into the inverter and some other random points on the board. The huge 450 V capacitor on the power board is measuring 250 V (measured in ||)

The two brown resistors read 23.8 V in series.

The power connector pins measured in series read (starting from the white triangle you see in the picture by the C866 marker)
23.8, 23.8, 23.8, 23.8, 23.8, 0, 0, 0, 0, 0, 0, 3, 2, 0 V

When measuring the voltage in || across the capacitors I swapped out I get a 23.8 V measurement across all of them.

I didn't take any measurements on the inverter board as I wasn't sure what kind of voltage the bad boy can crank out, and I didn't feel like testing my luck. If it's something you guys think you need then let me know.

At this point, I would really like to get this thing fixed with some capacitor/other minor repair as a replacement inverter board for this thing looks like it will run me $70 (which I wouldn't mind doing if I knew that would solve the issue!)

(If you want original high def pictures of board let me know and I can try and upload them to a 3rd party site)

Thanks,
Sam

[wasmundt]

Re: Dell U2410f

Another thing to possibly point towards the panel is this quote I found while searching the issue on bit-tech forums.

From GoodBytes who seems to be pretty rebutable on the forum,

"Dell has the most courage... they sent to reviewers U2410 early revision A00, where LG (panel used in the Dell U series monitor) had A LOT of production problem at the time (that was in 2009, it affected many LG IPS users)."

What do you know, I have a 2009 A00 U2410F version Also, any chance of sweet talking myself into a repair for a known issue even though I don't have any original purchasing information is now gone as I swapped out the capacitors on the power board

Thanks for the input,
Sam

[budm]

Re: Dell U2410f

Can look at the sceen in the dark to see if the backlights even flash on for second, so far the voltage readings are OK for the inverter board, but the reading on the 450V cap is too low, it should be around 390~400VDC due to the PFC Voltage booster circuits. What is an AC voltage in your country?

[wasmundt]

Re: Dell U2410f

I will try to strip it down as far down as I can to try and let as much light leak out as possible (if there is any ) will get back to you guys in a little bit.

[wasmundt]

Re: Dell U2410f

hey guys, the monitor stays black as day throughout the entire process. I was able to hook it up to my laptop through VGA and I can see the picture throughout the entire screen when shining my flashlight directly into the monitor.

If you were trying to see if it was the 2 seconds to black issue, I don't think this is it as it doesn't light up at all (even for a split second)

Thanks, keep the suggestions coming.

[jetadm123]

Re: Dell U2410f

Try checking the fuse on the inverter board. It the small white rectangular component marked F001.

[wasmundt]

Re: Dell U2410f

Yup, just got done measuring that after reading up on some other things. The fuse is labeled, as you mentioned, F001 but also 6.3 A, and 125 V. Measuring the Voltage I am seeing it as 23.8 V (the same as the capacitors, and the leads coming into the board)

Also, would like to correct my typo above - the large 450 V capacitor is reading a difference of ~240 V, -56 on 186 on the (-/+) terminals.

**Edit** I was trying to measure some of the voltage regulators, and I nicked the small resistor alongside the large 450 v capacitor. Needless to say, I got a nice "pop" for my troubles. It caused the voltage reading across the capacitor to drop by about 100 V. I de-soldered it and attached pictures of the resistor. It's got a 0.2 Ohm labeling. Other labeling, an undistinguishable character followed by 992 and another label of F13? These are the best I can make out of it. Any ideas as to what exactly it is would be great so I can repair my blundering

Pictures up soon.

[budm]

Re: Dell U2410f

"the large 450 V capacitor is reading a difference of ~240 V, -56 on 186 on the (-/+) terminals" I do not knopw what you mean, you should measure it at the two legs of the cap, it should have a bour 165VDC when the monitor is plugged in, then it should go up to 390~400V when power up (if your line voltage is 120vac). When work on primary side of the circuit, do not use the chassis as the ground ref, you have to use the negative leg of the cap as the ground ref point.

[wasmundt]

Re: Dell U2410f

.2 ohm F1J Fu 992

Those are the markings on the resistor I burned out, but not really sure what I should use to replace it.

[budm]

Re: Dell U2410f

That may be the resistor for the Source pin of the MOSFET, you need to trace that out, or it can be the protection resistor in the B+ Line. Need to see the closed up loaction of that resistor and the trace on the bottom side to see how it is connected in the circuits.
0.2 Ohm 1/2? MOX (Metal Oxide type).

[wasmundt]

Re: Dell U2410f

Ok, so another piece of the puzzle is that it's labeled as a FRXXX on the circuit board, not just RXXX, not sure what the distinction is.

Pictures of the surrounding circuit are attached.