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Old 01-02-2012, 09:57 PM   #1
Korpsicle
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Question Dell E152FPb

Noobie Incoming.

I got this monitor from a friend that had some flickering issues. Thwacking it worked, but after a short time the unit will light up the power button, but an image will never present.

So I ripped it open and have board ETL-XPC-801

And thus, I am here.

Any help would be appreciated. It looks like the caps in picture 3 might be bad, but I'm not sure if there's something else that might be bad.
Attached Images
File Type: jpg photo 1.JPG (1.35 MB, 49 views)
File Type: jpg photo 2.JPG (1.21 MB, 28 views)
File Type: jpg photo 3.JPG (1.06 MB, 28 views)
File Type: jpg photo 4.JPG (1.39 MB, 24 views)
File Type: jpg photo 5.JPG (1.21 MB, 16 views)

Last edited by Korpsicle; 01-02-2012 at 10:10 PM..
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Old 01-02-2012, 10:00 PM   #2
smason
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Default Re: Dell E152FPb

You will need to upload the photos here, use the manage attachments button below.

Many won't go to off site photo hosting sites, because they can (and recently have) contain malware.
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Old 01-02-2012, 10:02 PM   #3
Korpsicle
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Default Re: Dell E152FPb

My apologies. I figured an album view would be easier is all. Also they were taken with my iPhone in HDR so they're large files.

Edit: Ran into sizing issues, pictures were over 2k pixels, attached to post 1.

Last edited by Korpsicle; 01-02-2012 at 10:09 PM..
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Old 01-02-2012, 10:37 PM   #4
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Default Re: Dell E152FPb

These monitors are notorious for a number of problems, but first let's clarify the problem. At present, do you get any sign of backlights?

If there is no sign of backlights, can you see a faint image if you shine a bright light on the screen while the monitor is hooked to a working computer? If you can, you are a victim of crappy solder.

Heating and cooling cycles cause the solder around the two transformers to crack and give intermittent contact. This causes either the transistor pair Q759, Q760 or Q739, Q740 to short. This blows picofuse Pf761 (PF751?). Q751 and Q743 may also be damaged.

Check the picofuse to see if is open. Check all of the above transistors for shorts. Complete kits of parts are available on eBay.

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Old 01-02-2012, 10:40 PM   #5
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Default Re: Dell E152FPb

This is the standard Benq board with multiple potential problems.

1) All the components circled in red MUST be resoldered or reflowed due to poor solder joints. MANDATORY. If you ignore this step, don't be surprised if your monitor dies again.

2) All the components (transistors and fets) circled in green should be checked for shorts.

3) The picofuse is circled in yellow. A good fuse should measure less than 1.0 ohms.

4) PlainBill beat me by 3 minutes while I was doodling in paint.

5) And smason is correct. I won't even bother to look at pics hosted offsite.
Attached Images
File Type: jpg photo 1.JPG (595.9 KB, 80 views)
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Last edited by retiredcaps; 01-02-2012 at 10:43 PM..
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Old 01-02-2012, 10:44 PM   #6
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Default Re: Dell E152FPb

Quote:
Originally Posted by retiredcaps View Post
This is the standard Benq board with multiple potential problems.

1) All the components circled in red MUST be resoldered or reflowed due to poor solder joints. MANDATORY. If you ignore this step, don't be surprised if your monitor dies again.

2) All the components (transistors and fets) circled in green should be checked for shorts.

3) The picofuse is circled in yellow. A good fuse should measure less than 1.0 ohms.

4) PlainBill beat me by 3 minutes while I was doodling in paint.
Yeah, I've got some apple crisp calling to me from the kitchen.

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Old 01-02-2012, 10:55 PM   #7
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Default Re: Dell E152FPb

Okay, well I've good good and bad news. Mostly bad news. The screen is working fine now that everything is plugged back in.

But it was doing this before. It would work fine, then it would flicker, I'd hit it and it'd turn back on, then it wouldn't even flicker and I gave up. This is was a couple weeks ago. I hooked it up a few days ago and it just worked, had to hit it once I think yesterday, and then today it just wouldn't try. Which is why I took it apart.

@Both I don't have access to my multimeter, I took it to work today and forgot to bring it home. I'll have to try that tomorrow when I get home from work.

@retiredcaps
1) My soldering iron needs new points I can pick them up tomorrow and I'll do that.

2) When you say check for shorts, what kind of readings should I get at what settings?

3) again, sorry to sound so helpless, what settings should I run at.
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Old 01-02-2012, 10:58 PM   #8
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Default Re: Dell E152FPb

Quote:
Originally Posted by Korpsicle View Post
2) When you say check for shorts, what kind of readings should I get at what settings?
See

http://www.badcaps.net/forum/showpos...4&postcount=19

specifically the section on Multimeter, 2) Shorted Transistors/MOSFETs, and 3) Open fuse.

However, if your monitor is working, it is likely the poor soldering causing your grief. If resoldering doesn't solve the problem, it could be caps with high ESR (ohms). ESR drops as the monitor warms up and allows the lcd to work.

Last edited by retiredcaps; 01-02-2012 at 11:00 PM..
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Old 01-02-2012, 11:02 PM   #9
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Default Re: Dell E152FPb

Well that's good news.

Would it be easier to reflow with a heatgun from my station? Or check for cracked points and re-solder? I also have a small oven I frequently reflow X360's with at my disposal.

Edit: also, thanks for the link. Bookmarked
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Old 01-02-2012, 11:06 PM   #10
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Default Re: Dell E152FPb

Use a solder iron and reflow or resolder each of those circled components works 100% of the time. No baking is required.

I made the mistake of not resoldering/reflowing the inverter transformer and in about 25 hours, I had a blown picofuse again. It was my first repair of a Benq board. Now I have done 5 or 6.
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Old 01-02-2012, 11:09 PM   #11
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Default Re: Dell E152FPb

Oh cool. Thanks a ton. I'll be sure to do that in the morning then and will post with results.
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Old 01-03-2012, 11:40 AM   #12
Korpsicle
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Default Re: Dell E152FPb

Well I tried re-soldering some of the connections however upon power on the image turns on for a second or two and the backlight goes out. I can still see an image very faintly on the screen.
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Old 01-03-2012, 12:54 PM   #13
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Default Re: Dell E152FPb

Quote:
Originally Posted by Korpsicle View Post
Well I tried re-soldering some of the connections however upon power on the image turns on for a second or two and the backlight goes out. I can still see an image very faintly on the screen.
have you resoldered all the components that retiredcaps circled ??
you may have had a failing ccfl that has completly failed now
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Old 01-03-2012, 03:04 PM   #14
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Default Re: Dell E152FPb

Quote:
Originally Posted by Korpsicle View Post
Well I tried re-soldering some of the connections however upon power on the image turns on for a second or two and the backlight goes out. I can still see an image very faintly on the screen.
Time to troubleshoot using the multimeter as per posts #4 and #5.
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