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Old 11-30-2012, 07:41 PM   #1
ForensicFixer
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Default No Power Dell U2410 Monitor

Hi Guys, Iíve been looking at this repair for a number of days and hope to use it to further my knowledge. However Iíve reached my current knowledge limit and would be grateful of any help offered.

This fault in a Dell U2410 monitor presents itself as a no power fault. No lights on power button and no change to the screen. I tested the connector and ribbon on the bottom right of the power board and found 3.70 volts on the first four wires from the left and 0.05 volts on the red wire far right. All other wires show 0 volts.

Not knowing if it was the voltage being pulled down by a faulty main board or a low power output from the power supply board I disconnected the main board and retested.

With the main board disconnected from the power board the voltages rise to 5.15 on the left four and 4.68 on the red wire. To me this suggested the power board was running low outputs and 4.68 is still not right. I have tested the caps with an ESR meter in circuit and a couple which gave poor readings removed and tested out of circuit. The highest reading on the cold side was 0.46. The big ĎEliteí on the hot side shows 0.61 when tested in circuit.

Iíve done a visual inspection of joints and components with nothing unusual noted.
Unfortunately this is where my knowledge ends. Any help much appreciated.

Rodger





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Old 11-30-2012, 10:26 PM   #2
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Default Re: No Power Dell U2410 Monitor

What voltage do you have on that large 450v cap C854? It should be about 380~400vdc on the two legs of that cap, be careful since you are working on the hot side of the circuit.
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File Type: jpg PS redlined1.jpg (163.4 KB, 240 views)
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Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/

TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809

Last edited by budm; 11-30-2012 at 10:43 PM..
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Old 12-01-2012, 03:07 AM   #3
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Default Re: No Power Dell U2410 Monitor

Hi thanks for the interest, I thought it looked fairly normal as it is sitting at 326v
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Old 12-01-2012, 12:41 PM   #4
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Default Re: No Power Dell U2410 Monitor

Hi guys,
same situation at my desk.
Usually I leave monitor all time ON but yesterday I pushed power button (don`t know why I did it this time, grrrrrr). In meantime there was power down and could be UPS did his job for 5-10 minutes but dark was for longer period.
After I wanted to continue work there was no signs of life.
Now is dissasembled with multimeter & hot Weller by side and question sign over my head.
Same voltages.
I`ve found this: http://www.josepino.com/computer/howto-repair-dell
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Old 12-01-2012, 02:03 PM   #5
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Default Re: No Power Dell U2410 Monitor

Quote:
Originally Posted by davor View Post
Hi guys,
same situation at my desk.
Usually I leave monitor all time ON but yesterday I pushed power button (don`t know why I did it this time, grrrrrr). In meantime there was power down and could be UPS did his job for 5-10 minutes but dark was for longer period.
After I wanted to continue work there was no signs of life.
Now is dissasembled with multimeter & hot Weller by side and question sign over my head.
Same voltages.
I`ve found this: http://www.josepino.com/computer/howto-repair-dell
That is great if you have a Dell E172xx If you have got one, do what it says
and why have you posted in a Dell U2410 Thread

If you have a Dell U2410 the info is of little as it is totally different.
So please tell us which.
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Old 12-01-2012, 02:27 PM   #6
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Default Re: No Power Dell U2410 Monitor

Forensicfixer
Is it your machine? do you have any history of the breakdown - power surge
lightning strike - wouldnt turn on first time for weeks then wont come on etc.

In pic 2 I am wondering about the end cap near the connector - could be C932 Pics are good thanks but eyes are tired. The circle on the board is usually an indication of the size of the cap that sits on it. In this case the volume of the cap is probably a third of the expected size. The back of the board suggests that it was not factory soldered?
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Old 12-01-2012, 03:01 PM   #7
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Default Re: No Power Dell U2410 Monitor

At 326V that means the PCF did not turn on to kick it up to about 400V. I still like to know what DC voltages you get at those 3 I circled.
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Old 12-01-2012, 03:30 PM   #8
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Default Re: No Power Dell U2410 Monitor

Budm - think he told us in the OP
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Old 12-01-2012, 04:38 PM   #9
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Default Re: No Power Dell U2410 Monitor

Hi I have no plan to hijack the topic, but I own the U2311H and the USB ports (HUB) it got damaged due a 3G mobile stick that sorted out and died.

Is it possible to take a close up picture just of the USB ports and controller so to see if there is any fuse on it ?

My monitor still works great as screen, what ever happened as damage it did stopped at the USB controller.
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Old 12-01-2012, 05:41 PM   #10
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Default Re: No Power Dell U2410 Monitor

selldoor

The monitor was bought off eBay so unfortunately I've no history for it. Your right about C932. Its a 50v 47uF Su'scon cap. I tested all caps in circuit with an esr meter but 932, 864 and 957 gave either erratic or poor results. Therefore I removed these three for testing. C932 tested out of circuit esr 0.38 and 48.45uF at 100kHz.

Tested your circled caps, from left to right, 1 and 2 give 0v while 3 gives 5.15v when detached from mainboard and 3.70 when attached.
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Old 12-01-2012, 07:56 PM   #11
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Default Re: No Power Dell U2410 Monitor

@selldoor, per post 1 "With the main board disconnected from the power board the voltages rise to 5.15 on the left four and 4.68 on the red wire. "
Unless I did read it correctly, on your post 8, only one output is working (3.7V) the other two are 0V all three outputs are fed by the same transformer so I cannot see how other two are dead with 0V output. Unless there are fuses on the other two outputs. I need to look at my own pictures again.
I would like to know the P/N of the two regulator on the top side of the board, I expect to see outputs at B+2 and B+3.
I also expect to see about 400vdc on the large cap also.
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Last edited by budm; 12-01-2012 at 08:09 PM..
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Old 12-01-2012, 11:58 PM   #12
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Default Re: No Power Dell U2410 Monitor

Sorry for link...just first hit after shock.
Here is 3rd condenser on my board - also smaller than circle.
And I`ve found traces of hand soldering on resistor R856 (up-left from Q853).
C854 voltage = 325V.
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Old 12-02-2012, 07:02 AM   #13
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Default Re: No Power Dell U2410 Monitor

Davor - ok that is great then- welcome- that has shot down my cap to circle size theory
what values has your c932 marked on it and do you have the same voltage on the connecter as Forensic Fixer.

Can you help Kiriakos with a pic of USB Ports.
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Old 12-02-2012, 02:22 PM   #14
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Default Re: No Power Dell U2410 Monitor

@selldoor
I have attached pictures of the two regulators. Their markings are as follows, nearest to connector with marking on board, U930, on component AX1202-12 1013A. The second is marked on board as Q930, on component 9972GS A11221.

@Kiriakos
I have attached pictures of both sides of the USB hub. Hope this helps.

I think I need a photography course.
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Old 12-02-2012, 03:40 PM   #15
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Default Re: No Power Dell U2410 Monitor

Quote:
Originally Posted by selldoor View Post
Davor - ok that is great then- welcome- that has shot down my cap to circle size theory
what values has your c932 marked on it and do you have the same voltage on the connecter as Forensic Fixer.

Can you help Kiriakos with a pic of USB Ports.
C932 = 47uF/50V

If look at 14-pin connector where red wire is on right (pin 14) and voltmeter red wire is on it, than voltages are:

DISCONNECTED STATE
1-4 = -0,466V
5-10 = +4,66V
11 = -1,16V
12 = +4,60V
13 = +4,04V

CONNECTED STATE:
1-4 = -3,64V
5- 13 = +48 mV

I dont think there is much to repair on USB/Reader board
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Old 12-02-2012, 03:51 PM   #16
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Default Re: No Power Dell U2410 Monitor

Quote:
Originally Posted by Kiriakos GR View Post
Hi I have no plan to hijack the topic, but I own the U2311H and the USB ports (HUB) it got damaged due a 3G mobile stick that sorted out and died.

Is it possible to take a close up picture just of the USB ports and controller so to see if there is any fuse on it ?

My monitor still works great as screen, what ever happened as damage it did stopped at the USB controller.
There are two fuses marked "G" as shown in the picture
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Old 12-02-2012, 04:03 PM   #17
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Default Re: No Power Dell U2410 Monitor

Quote:
Originally Posted by ForensicFixer View Post
@selldoor
I have attached pictures of the two regulators. Their markings are as follows, nearest to connector with marking on board, U930, on component AX1202-12 1013A. The second is marked on board as Q930, on component 9972GS A11221.

@Kiriakos
I have attached pictures of both sides of the USB hub. Hope this helps.

I think I need a photography course.
Good light is the key - daylight if possible - haha your not far from here so
what daylight !!


It was Budm who asked for the regulators - one is a regulator the other is a mosfet (same package)

Think there are tests in here start post19
http://www.badcaps.net/forum/showthread.php?t=10419

data sheets
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File Type: pdf 2984981238201637.pdf (328.7 KB, 124 views)
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Old 12-02-2012, 05:11 PM   #18
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Default Re: No Power Dell U2410 Monitor

I did a quick test on the mosfet in circuit using the 200 ohm test.
Pin 1 - 2 open circuit
Pin 1 - 3 open circuit
Pin 2 - 3 sometimes flashes 165.9 then open circuit, other times open circuit

I won't be home again till Tues night so will test the mosfet then.
What do you think of the regulator results?

Last edited by ForensicFixer; 12-02-2012 at 05:18 PM.. Reason: Error on component
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Old 12-02-2012, 05:23 PM   #19
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Default Re: No Power Dell U2410 Monitor

Quote:
Originally Posted by ForensicFixer View Post
I did a quick test on the mosfet in circuit using the 200 ohm test.
Pin 1 - 2 open circuit
Pin 1 - 3 open circuit
Pin 2 - 3 sometimes flashes 165.9 then open circuit, other times open circuit

I won't be home again till Tues night so will test the mosfet then.
What do you think of the regulator results?
Hmm The 3 pin one is the mosfet it looks ok

The 5pin one is the regulator - you need to look at the datasheets
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Old 12-02-2012, 05:30 PM   #20
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Default Re: No Power Dell U2410 Monitor

Yeh realised my mistake and couldn't leave it!!
I'm guessing the test is between ground, vcc and out. That would make it pins 1,3 and 5.
Am I looking for similar results?
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