No Power Dell U2410 Monitor

[dinamichhhh]

Re: No Power Dell U2410 Monitor

Just say that you do not own an LCR meter so to check them.
In this case just trust some one else to repair it for you.

Today I took the boards to my workplace and used ESR meter to measure all electrolytic capacities on both boards. None of them showed unusually high ESR value.

I also looked closely at boards with stereo microscope and found nothing unusual. All elements marked as FBxxx, which are probably some kind of fuses, were measured are conducting.

Any more suggestions?

[budm]

Re: No Power Dell U2410 Monitor

see picture:
What do you get at B1, 2, and 3?

[Kiriakos GR]

Re: No Power Dell U2410 Monitor

all caps look OK.

Just say that you do not own an LCR meter so to check them.
In this case just trust some one else to repair it for you.

[dinamichhhh]

Re: No Power Dell U2410 Monitor

Hi all,

Yesterday my Dell U2410f died just like original poster's ForensicFixer and another poster davor. Monitor was in sleep mode, power led was slowly blinking in orange color. Then I pressed the power button. Monitor turned off and I was unable to bring it back to life since then.

Since my warranty expired about one month ago, I decided to open it and do some forensics with multi-meter an scope. Here are my observations.

First of all this monitor is a bitch to open, I had a real struggle to start to crack it open. I found the weakest spot on the right hand side bezel and with much difficulty managed to pry it open with knife. I then inserted plastic lever and managed to pop open all clips without braking any of them.

When connected to mains 235V AC 50Hz, all boards connected (as came from factory), I measured 3.7V and 12V on the end of power supply board. The 12V is blocked from going onto main board by power mosfet and another chip (probably regulator). The 3.7 volts gets to main board.

Moving on to main board. There are various voltage regulators on there. SRAM regulator gives 1.8V, which is correct voltage according to datasheet for h5ps5162ffr-s6c. All othere that I measured are working as per their datasheets.

Usb hub and card reader are supplied by 3.7V (probbably raw voltage from power board), which I think is strange, isn't USB supposed to be 5 volts?

Power key is powered via pullup resistor, when not pressed it outputs 3.4V signal, which goes somewhere towards CPU. When pressed signal drops to 0V. This looks OK.

The crystal oscillator for main CPU is running at correct frequency (nearly 20MHz) although the signal is not square, its is sinusoidal. Which is probably OK.

On the underside of main board is serial flash eeprom. Tried to measure SCLK and SI (serial input) signals - nothing there, CPU does not try to communicate with it.

There are also no active waveforms towards SRAM, which makes me believe that the main CPU is in some kind of suspended state and is waiting for wake-up signal. I really have to trace signal from power button to the CPU and measure it.

Same as other reported, when I remove main board from power board, the 3.7V voltage rises to 5V. Voltage across main capacititor C854 is in both cases same 325V. Which is expected (roughly input voltage times sqrt(2) ). So PFC never wakes up, which is logical since CPU is not waking it.

My conclusion: I see no immediate problem in power board. It looks like main CPU is stuck and can't wake up. Maybe firmware is corrupt? There are no obvious burnt elements on either board, all caps look OK.

Anybody have any idea what to do next? davor did you managed ti fix it?

[davor]

Re: No Power Dell U2410 Monitor

I've forwarded monitor to a friend, a kind of very patient electronics (experienced) freak and it works on it for months now - stuck with some component marked S3.
Does anyone on the planet has schematic?!?

[julius22]

Re: No Power Dell U2410 Monitor

Any progress?

I would be very interested to hear about it...

[Hampus]

Re: No Power Dell U2410 Monitor

Thank you budm for the quick reply!

Here are my results. Are these fine and is there anything else that may be bad like the PFC IC (I851?)?

• RT851 shows ~3 Ohm
• There is residual V over C854 (from other capacitors?), so no short over the PFC if I understand the question (to check R between "Catode side and the primary Ground ref").
• FR851 is ~1 Ohm.
• I am unsure of what to do with Q853. I couldn't get an R measurement, but it seems both S and G are ~grounded and none of the pins shorted (I guess there could not be any short w/o power connected anyways).

All probing was done w/o mains connected.

Can I check Q853 somehow, or just replace the D856 diode and return power? Check anything (Q853) at that point?

Thanks a million

[budm]

Re: No Power Dell U2410 Monitor

Check to see if RT851 is OK, then check the resistance on the Catode side and the primary Ground ref which is the Neagtive pin of C854 to see if the Load connected to the PFC Voltage booster is shorted. Might as well check the the FR851 (Value), Q853.
You may also have a shorted MOSFET that drive the 19V SMPS transformer.

https://www.badcaps.net/forum/attach...4&d=1351220450

[Hampus]

Re: No Power Dell U2410 Monitor

Hi Guys!

Starting my monitor during normal usage (front button poweroff), a short loud humming sound ended in a bang and black smoke.
The only casualty I can find (looking at the non-component side) seem to be diode D856.

From pics and the remains I pieced it together as an 1N5406.

A) Does any of you think this is caused by a broken component elsewere that I should replace so that it does not happen again (or something worse does)?
B) Any quality issues I should consider when I pick up a new 1N5406?

I have a basic understanding of electronics, but most of the electronics design here is beyond me at this point.

Hampus

[davor]

Re: No Power Dell U2410 Monitor

Right, VR's are direction where may be the solution.
Finally I've give up and now monitor is for allmost 2 months waiting for some VR to arrive (one local electronics freak was last who wanted dell on his desk).
No call from him yet (hm, maybe kids around his building are playing with components out of IFD - identified flying dell).

I dont think he has any schematics.

[julius22]

Re: No Power Dell U2410 Monitor

Hi,
I have a 2410f with exactly the same problem.

Does anyone know where to find a service manual or just schematics for this monitor?

[dullishpage]

Re: No Power Dell U2410 Monitor

I'm have the same issues here, so it seems it may be the voltage regulators? I had the same issue were it wouldn't power on, remove ac power press power button, and then ac power attached and press button on. But finally as i predicted that method stopped working for me. I checked out the power supply board, looks ok mostly. No exploded/leaking caps, which is what i was hoping for.

[davor]

Re: No Power Dell U2410 Monitor

FY DELL!
Just turned off monitor and can't power it on!!!
WTF is now?!

[davor]

Re: No Power Dell U2410 Monitor

Works as new. Forget VR's - focus on badcaps.

[davor]

Re: No Power Dell U2410 Monitor

Still nothing here...
Ordered caps repair kit.
Will post results after change.

[selldoor]

Re: No Power Dell U2410 Monitor

That is ok - not everyone knows the warranty can be 3 years.
It is often more difficult to find a partial fault than a full breakdown.
It could still be a firmware glitch.
We can often help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) 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...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

It will be useful if you can say a bit about yourself - skills tools etc.

[poteroa]

Re: No Power Dell U2410 Monitor

I bought it just few days ago, second hand..
I don´t have the damn order number that dell wants, (the warranty is calculated from the delivery date), but I know it should have the 3 year warranty.
I really would like to find the problem myself rather than to send it for repair.

[selldoor]

Re: No Power Dell U2410 Monitor

Hi Poteroa- Have you had it from new - is it still under warranty - may have been a 3 year one?

[poteroa]

Re: No Power Dell U2410 Monitor

Hi all!

I have the same u2410 monitor with same issues. Updated earlier to A02 firmware, no help.
I found info from dell site that if you unplug the power cord, press the power button for 10-20+ seconds and plug back, the monitor might start again.
Mine starts with this method, but if I power off, I have to use the same method to get it on again.

I have been trying to figure out the power board, but looks like the issue might be on the mainboards side. Capacitors look fine, no swollen ones anywhere, as I think it could be the reason. Haven´t measured any of them yet, but checked all the diodes, mosfets and resistors, all checked ok.

Anyone with ideas why the "resetting" with power button pressed cures the issue?
After I get the monitor on, it stays on and works flawlessly.

-Pete

[selldoor]

Re: No Power Dell U2410 Monitor

Hi - Probably need Budm or Tom to confirm but I think it is a sot23 mosfet.
I have looked for the markings to try and find a datasheet but no joy.
Perhaps post a pic of it in general electronics forum - someone might recognise.

Note the board markings on it for source drain and gate. - You could always
test it for shorts. Problem could also be with the linked transistor which might
switch on/off the gate?