Re: No Power Dell U2410 Monitor
[B]Main board:[/B]
[ATTACH]77746[/ATTACH]
Here is a rough schematic of power distribution on main board. Measured voltages are in red.
As we can see, the board is supplied with 3.7V at pins 11-14, since CPU is driving pin 1 to 0V.
At the same time CPU is also driving Q702 on, which supplies USB hub and USB ports with 3.7V. At the same time linear regulator AS1117L which should generate 3.3V for USB controller can't deliver 3.3 volts and only manages to output 2.7V. [B]This means to me, that...
dinamichhhh
New Member
Last Activity: 01-26-2014, 07:22 AM
Joined: 12-29-2013
Location: Ljubljana
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Re: No Power Dell U2410 Monitor
[B]Power board:[/B]
[ATTACH]77745[/ATTACH]
Here is a part of power board circuit, the output stage that generates three voltages for main board. This part is connected to main board via 14 pin connector/cable, pin 1 is red color others are black.
Measured voltages are drawn on schematic in red color. These are measurements of my device when all boards are connected together, plugged into mains 235V 50Hz AC.
The most important part is voltage at point V2, which is supplying main board via...Leave a comment:
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Re: No Power Dell U2410 Monitor
Time to recap and look back.
My problem with U2410 is that it wont power up. When connected to mains it just stays off, no light, no leds, nothing. Pressing power button does nothing. Leaving it unconnected for a long time did not solve anything.
Since my warranty expired one month ago, I took it apart and looked inside with multimeter oscilloscope and ESR meter.
No obvious fault was found after visual inspection (also with microscope), no bulging or leaking caps.
Measured all electrolytic...Leave a comment:
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Re: No Power Dell U2410 Monitor
I haven't given up, yet
I uploaded a bunch of photos showing dis-assembly, boards and part of schematic. You can find them [URL="https://drive.google.com/folderview?id=0BwVO063TrudAQ2U0LW54ZzFxRnM&usp=drive_web"]here[/URL].Re: No Power Dell U2410 Monitor
I haven't given up, yet
I uploaded a bunch of photos showing dis-assembly, boards and part of schematic. You can find them [URL="https://drive.google.com/folderview?id=0BwVO063TrudAQ2U0LW54ZzFxRnM&usp=drive_web"]here[/Leave a comment:
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Re: No Power Dell U2410 Monitor
Thanks for support. I am indeed an electrical engineer, but I am mostly working on software side of embedded projects.
When you get a board like this without any schematics it is difficult to do anything. I tried the obvious stuff, then read all the information I could find via google and then tired some more test. When I got stuck without further ideas to try I posted to this forum....Leave a comment:
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Re: No Power Dell U2410 Monitor
I got excacly the same results as previosu posters.
When power and main board are connected together we get:
* B1 3.7V
* B2 0V
* B3 0V
When they are disconnected we get:
* B1 5V
* B2 0V
* B3 0V
Voltage at B2 is blocked by N channel mosfet, drain side has 12V. Voltage at B3 is blocked by some other part, probably some kind of voltage regulator, its source voltage is also 12V and present. They are probably turned on later by CPU when...Leave a comment:
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Re: No Power Dell U2410 Monitor
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?...Leave a comment:
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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...Leave a comment:
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