Dell E153FPB Back Light problem

**PlainBill** · 11-05-2009, 04:25 PM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

I checked again on 50 volt range with analog meter, still reading 10 volts, checked on 10 volt range reads maxed out, just a hair over 10 volts AC

AC??? It should be DC.

PlainBill

**freakytiki4u** · 11-06-2009, 06:11 AM

Re: Dell E153FPB Back Light problem

Yeah I knew that. (tries to avert your gaze) LOL , tested again with DC (ahem) and this time it showed 5 volts (bangs head on desk.)

**freakytiki4u** · 11-06-2009, 06:13 AM

Re: Dell E153FPB Back Light problem

you wont tell anyone I did that will you? LOL

**PlainBill** · 11-06-2009, 07:29 AM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

you wont tell anyone I did that will you? LOL

Of course not. If I did, you would tell everyone the TV story.

PlainBill

p.s. We'll get back to the monitor once I wake up.

PB

**freakytiki4u** · 11-06-2009, 09:27 AM

Re: Dell E153FPB Back Light problem

LOL, too funny, Thank You Sir and Im sending a cup of Joe your way

**PlainBill** · 11-06-2009, 10:14 AM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

LOL, too funny, Thank You Sir and Im sending a cup of Joe your way

There are three possible causes of this problem. The power supply itself; the inverter,or the logic card. The only time I saw something similar was when their were shorted transistors in the inverter. This overloaded the power supply. HOWEVER, you have determined the 5V supply is stable. Next you can eliminate the inverter as a cause. This is the datasheet for the two ICs (actually paired power mosfets). Check each section of the pair for shorts. Check the resistance between D1 and G1, between G1 and S1, and between D1 and S1; repeat for D2 and G2, between G2 and S2, and between D2 and S2. Do this for BOTH ICs. If there are no shorts, unsolder one end of the jumper I have circled in the attachment. This completely isolates the inverter from the power supply. Now test the board in the monitor - no need to hook up the backlights. All we're interested in at this point is the behavior of the green power light.

The other two possible causes are the logic board, or more bad caps in either the power supply or the logic card.

PlainBill

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**freakytiki4u** · 11-06-2009, 10:50 AM

Re: Dell E153FPB Back Light problem

I think I angered it. When I put the board back in to test it started smoking from the actual corner of the screen itself. LOL, Im just going to call this one a bust. Thank you for your patience with me. Until next time

**PlainBill** · 11-06-2009, 11:56 AM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

I think I angered it. When I put the board back in to test it started smoking from the actual corner of the screen itself. LOL, Im just going to call this one a bust. Thank you for your patience with me. Until next time

Sometimes sacrifices are necessary. When it's a burnt offering, it's better to sacrifice a monitor than and human - well, some humans.

PlainBill

**freakytiki4u** · 11-06-2009, 08:25 PM

Re: Dell E153FPB Back Light problem

I totally know what ya mean, I've been married 3 times. LOL

**PlainBill** · 11-06-2009, 08:35 PM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

I totally know what ya mean, I've been married 3 times. LOL

Some people learn faster than others. At one time I introduced my wife as 'My first wife.' She retaliated by referring to me as her 'starter Husband.' I decided to refer to her as 'My trophy wife.' Things got a lot calmer after I came to my senses.

PlainBill

**EGuevarae** · 11-06-2009, 10:35 PM

Re: Dell E153FPB Back Light problem

Originally posted by freakytiki4u

I think I angered it. When I put the board back in to test it started smoking from the actual corner of the screen itself. LOL, Im just going to call this one a bust. Thank you for your patience with me. Until next time

Save the monitor. You can use parts of it to test (or even fix) other unit(s).
I have a box (not too big, but still a box) full of either received dead units, units killed by me in the name of science, or killed by others and donated to me. That box is a very precious resource sometimes ...

**freakytiki4u** · 11-07-2009, 07:44 AM

Re: Dell E153FPB Back Light problem

Excellent idea!

**jschiefer** · 11-08-2009, 09:59 PM

Re: Dell E153FPB Back Light problem

So I read pretty much the entire thread and im afraid im still not sure where to start. I have the Dell

E153FPB. When i turn on the LCD screen it flashes white for a second and then goes black. I cannot see any image on the screen but the LED power light stays on.
I tested the fuse PF751 with an ohm meter and it has resistance, so im thinking its not that.
I also flipped the board over and didnt see any cold solder joints, fixed a couple that were debatable.

Sorry if this is a double post. I couldnt look any longer lol

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**EGuevarae** · 11-08-2009, 10:03 PM

Re: Dell E153FPB Back Light problem

Originally posted by jschiefer

So I read pretty much the entire thread and im afraid im still not sure where to start. I have the Dell

E153FPB. When i turn on the LCD screen it flashes white for a second and then goes black. I cannot see any image on the screen but the LED power light stays on.
I tested the fuse PF751 with an ohm meter and it has resistance, so im thinking its not that.
I also flipped the board over and didnt see any cold solder joints, fixed a couple that were debatable.

Sorry if this is a double post. I couldnt look any longer lol

Used a flashlight to see if the panel is on and image is displayed (you would not see it clearly if the CCFLs are off but if you don't have an image, it's not the inverter or tubes.
Post series/brand/capacitance of caps, and test each of the four c5707s in there.

**jschiefer** · 11-08-2009, 10:06 PM

Re: Dell E153FPB Back Light problem

How do i test capacitance of the caps? I have a multimeter...

**EGuevarae** · 11-08-2009, 10:19 PM

Re: Dell E153FPB Back Light problem

Originally posted by jschiefer

How do i test capacitance of the caps? I have a multimeter...

I was referring to the specs of the actual caps installed, not the actual capacitance of the caps. If they are a known bad brand , suggestions of replacements would start flowing all over the place. That would be the first step for troubleshooting the board. Not all the problems are related to bad caps, but then again, bad caps can cause problems and interfere with troubleshooting, and as a general rule, if you are going to spend sometime with an open unit, it is usually viewed as a preventive measure, even if the caps are not failing but are of a brand that, under that conditions (heat and poor ventilation) would fail.
Also, again, look for bad solder because that units tend to have that problem, even if it is not easily visible with the naked eye.

**PlainBill** · 11-09-2009, 04:24 AM

Re: Dell E153FPB Back Light problem

Originally posted by jschiefer

So I read pretty much the entire thread and im afraid im still not sure where to start. I have the Dell

E153FPB. When i turn on the LCD screen it flashes white for a second and then goes black. I cannot see any image on the screen but the LED power light stays on.
I tested the fuse PF751 with an ohm meter and it has resistance, so im thinking its not that.
I also flipped the board over and didnt see any cold solder joints, fixed a couple that were debatable.

Sorry if this is a double post. I couldnt look any longer lol

Start with post 31 of this thread and follow the same advice.

PlainBill

**jschiefer** · 11-09-2009, 04:47 PM

Re: Dell E153FPB Back Light problem

Originally posted by Bobdee

Testing out of circuit with MM set on Diode Check
Red probe on B and Black on C, Should read about 600
Red probe on B and Black on E, Should read about 600

Testing for shorts between pins set MM to Buzzer and check
B + C
B + E
C + E
Probes both ways

I tested mine and got about 426 is that too far off?

**PlainBill** · 11-09-2009, 05:04 PM

Re: Dell E153FPB Back Light problem

Originally posted by jschiefer

I tested mine and got about 426 is that too far off?

Different brands of meters give different results. Were the results the same for all transistors?

PlainBill

**jschiefer** · 11-09-2009, 05:55 PM

Re: Dell E153FPB Back Light problem

Originally posted by PlainBill

Different brands of meters give different results. Were the results the same for all transistors?

PlainBill

Yes they all were. Its a cheap meter so i thought they were find.

I also looked at my LCD with a flashlight to see if i can see the image after it flashes white and i cant see an image. What does this mean?

Dell E153FPB Back Light problem

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