Badcaps.net Forum
Go Back   Badcaps Forums > Electronics Theory and Troubleshooting > Troubleshooting Computer Displays
Register FAQ Members List Social Groups Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 11-12-2008, 08:34 PM   #1
hybridge
New Member
 
Join Date: Nov 2008
Posts: 2
Default DELL E171FP White screen only.

Hello.
Just joined the sites, looks great here. Just have a question. I have 2 DELL E171FP that have same problem. Turn on ok green light on but only shows white screen, does not matter hook up to computer or not.
I am not new about repair the monitor but this one hard to trace without schematic. Thanks for any help.
hybridge is offline   Reply With Quote
Old 11-12-2008, 09:37 PM   #2
Krankshaft
Super Moderator
 
Krankshaft's Avatar
 
Join Date: Jan 2007
City & State: New Jersey, USA
Posts: 2,294
Default Re: DELL E171FP White screen only.

If it only shows a white screen thats probably an LCD panel board or video driver board problem.

Without schematic replacement of the board is the only viable option.
__________________
Elements of the past and the future combining to make something not quite as good as either.
Krankshaft is offline   Reply With Quote
Old 11-12-2008, 10:11 PM   #3
hybridge
New Member
 
Join Date: Nov 2008
Posts: 2
Default Re: DELL E171FP White screen only.

Thanks Krankshaft. I've been search on internet and not only me have this problem, thanks god. I will search more and will update if I find something. I bet some one else must solved this before. Thanks for any help.
hybridge is offline   Reply With Quote
Old 01-15-2009, 11:19 AM   #4
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: DELL E171FP White screen only.

Hello hybridge or any other help
I have got exactly same monitor and same problem, same symptoms plus added symptom, my on/off button does not turn off,
Have you or anyone else found a fix yet, please post and let us know, I have looked over boards for visible problems, found none thxs
bobdee

Last edited by Bobdee; 01-15-2009 at 11:27 AM..
Bobdee is offline   Reply With Quote
Old 01-16-2009, 05:37 AM   #5
2n3055
New Member
 
2n3055's Avatar
 
Join Date: Nov 2007
City & State: Amberg/BAYERN in the middle of Nowhere
My Country: Germany
Line Voltage: 230vac 50Hz
Posts: 5
Unhappy Re: DELL E171FP White screen only.

Quote:
Originally Posted by Bobdee
my on/off button does not turn off
Hallo
Button broken!
Take a lock at Krankshaft's Post
you got the same problem!
__________________
Operative Activity Replace Intelligence Wind calm

This post has been edited 275 times by 2n3055: Today, 12:93 PM
2n3055 is offline   Reply With Quote
Old 01-16-2009, 12:48 PM   #6
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: DELL E171FP White screen only.

Thanks for info
I have not checked out button, but will do so, the reason being is that I think that I have read in previous threads on Monitors with problems is that when they are turned off after fixing them, the Backlight stays on due to a faulty Mosfet.

So I am thinking the button issue in my case,that is not turning screen off, is due to it being linked to white screen issue. (Help anyone)

Have read Krankshafts post very carefully and understand but someone out there might have found a fix with luck, or read something positive on issue, and will post on it (help anyone)

Hybridge did you find one????

I should have and will check if button is faulty,and post back, also its not viable to me to buy a board because I let them go for pennys, so it will go for parts if no fix.

thanks bob
Bobdee is offline   Reply With Quote
Old 01-16-2009, 03:31 PM   #7
2n3055
New Member
 
2n3055's Avatar
 
Join Date: Nov 2007
City & State: Amberg/BAYERN in the middle of Nowhere
My Country: Germany
Line Voltage: 230vac 50Hz
Posts: 5
Default Re: DELL E171FP White screen only.

Hallo
Your problem is, the panel is working (white picture).
But the Signal processor don't work !
maybe i have the Service Manual

nice WE
2n3055 is offline   Reply With Quote
Old 01-16-2009, 04:13 PM   #8
2n3055
New Member
 
2n3055's Avatar
 
Join Date: Nov 2007
City & State: Amberg/BAYERN in the middle of Nowhere
My Country: Germany
Line Voltage: 230vac 50Hz
Posts: 5
Default Re: DELL E171FP White screen only.

Edit:
SM for this Dell E171fp search for Samsung LTM170EU or ACER AL1715P (M170EG01
2n3055 is offline   Reply With Quote
Old 01-16-2009, 04:34 PM   #9
Wizard
Badcaps Veteran
 
Join Date: Mar 2008
Posts: 2,297
Default Re: DELL E171FP White screen only.

White at power up is defective panel if the buttons and power is working on the mainboard (the small one that has input connectors on and power feed to it).

Cheers, Wizard
Wizard is offline   Reply With Quote
Old 01-16-2009, 04:36 PM   #10
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: DELL E171FP White screen only.

hello 2n3055 and everyone with this

Removed switch panel and lead to video board, and checked out continuity on all 4 buttons from end of lead, all OK tested fine,
that make the not turning off problem, somehow a part of the white screen problem, as I see it,please correct me if I am wrong,
I will strip board out again and resolder connections to connector on the board and reconfirm on/off switch is working from there.
thanks bob

Last edited by Bobdee; 01-16-2009 at 04:40 PM..
Bobdee is offline   Reply With Quote
Old 01-17-2009, 05:05 AM   #11
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: DELL E171FP White screen only.

Hello and sorry
Got cut short last night, it was out of my hands,router turned off.
Thanks 2n3055 for info on panels, Thanks Wizard for input, I will check out your info later,
I double checked on/off Button through to board solder joints, they are A1 OK, so it must be part of white screen issue when it dont turn off at button.

I will look at it again and get back to you later today
thanks bob
Bobdee is offline   Reply With Quote
Old 01-17-2009, 12:48 PM   #12
2n3055
New Member
 
2n3055's Avatar
 
Join Date: Nov 2007
City & State: Amberg/BAYERN in the middle of Nowhere
My Country: Germany
Line Voltage: 230vac 50Hz
Posts: 5
Default Re: DELL E171FP White screen only.

Hallo
@Bobdee
Check the Fuse at the Panelboard (F1)
2n3055 is offline   Reply With Quote
Old 01-17-2009, 02:10 PM   #13
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: DELL E171FP White screen only.

Thanks 2n3055
Already done so, after what Wizard said and its open, its going to be tough for me to replace becase of size, but now I need to know what takes them out, I think there is a dodgy IC on the video board, its a Dual P Channel power trench Mosfet according to data sheet, I dont Know how to check it other than replacing it,but can anyone tell me if this Mosfet would cause the fuse to go on panel as well as the problem with on/off button.

The Mosfet is marked U36 on board and is situated centre of Inverter connector and panel connector,also have link to D/Sheet as follows,

http://pdf1.alldatasheet.com/datashe...SI9933ADY.html

Any advice from anyone would be welcome and appreciated, also there is no rateing on fuse,

thanks bob
Bobdee is offline   Reply With Quote
Old 01-20-2009, 02:32 AM   #14
EGuevarae
Badcaps Veteran
 
EGuevarae's Avatar
 
Join Date: Nov 2008
City & State: Mecca, CA
Posts: 1,305
Send a message via MSN to EGuevarae
Post Re: DELL E171FP White screen only.

I just received an E171FP with the same problem. Will post pics as soon as I get my camera back.
__________________
There are 10 kind of people in this world: those that understand binary, and those who don't.
  • ASRock P43DE
  • Dual Core E6300 2.8GHz
  • 4gb DDR2-800
  • 500GB & 1TB SATA2 WD HDDs
  • 22x SATA DVD+RW
  • Windows 7 Pro
  • GeForce 8500GT PCIe
    2 x Vewsonic VP2130 21"
Badcaps.net Folding@home team member.
EGuevarae is offline   Reply With Quote
Old 01-20-2009, 07:15 AM   #15
Wizard
Badcaps Veteran
 
Join Date: Mar 2008
Posts: 2,297
Default Re: DELL E171FP White screen only.

Panel by default blocks light transmission when panel is without power even the backlight is lit. That is reason the panels is DARK when off and even tried to shine light through with a flashlight.

I had a very early 15" LCD panel that gone white (clear) that had -Ve bias dc to dc converter fail on the panel itself and had to operate on it.

Cheers, Wizard
Wizard is offline   Reply With Quote
Old 01-21-2009, 07:07 PM   #16
olivercan
New Member
 
olivercan's Avatar
 
Join Date: Mar 2008
Posts: 12
Default Re: DELL E171FP White screen only.

I just fix one dell E171fp,just replace the lcd panel.then let me know.good luck.
olivercan is offline   Reply With Quote
Old 01-21-2009, 08:27 PM   #17
EGuevarae
Badcaps Veteran
 
EGuevarae's Avatar
 
Join Date: Nov 2008
City & State: Mecca, CA
Posts: 1,305
Send a message via MSN to EGuevarae
Post Re: DELL E171FP White screen only.

I just opened it and it is exactly (almost) the same as a Samsung 172N that I have. All the internal parts are Samsung. The difference between this and the 172N is that the 172N has the inverter/PSU in one board and the Dell has them separated (3 boards in total), and that the lamp connectors are different. I'm going to swap the lamps and check the panel of the 172N in the dell (the Dell has, surprisingly, the white screen problem on startup...no menu, no nothing ....)
EGuevarae is offline   Reply With Quote
Old 01-22-2009, 07:30 AM   #18
Wizard
Badcaps Veteran
 
Join Date: Mar 2008
Posts: 2,297
Default Re: DELL E171FP White screen only.

Do not swap lamps. White LCD means terminal failure in LCD itself.

Cheers, Wizard
Wizard is offline   Reply With Quote
Old 01-22-2009, 08:07 AM   #19
EGuevarae
Badcaps Veteran
 
EGuevarae's Avatar
 
Join Date: Nov 2008
City & State: Mecca, CA
Posts: 1,305
Send a message via MSN to EGuevarae
Post Re: DELL E171FP White screen only.

Quote:
Originally Posted by Wizard
Do not swap lamps. White LCD means terminal failure in LCD itself.

Cheers, Wizard
The panel/screen in the 172N is working OK, just the power supply/inverter board is burned beyond repair. What I want to do is :
1.- Take the lamps out of the Dell panel (they work, as they light the screen)
2.- Put the Dell Lamps in the Samsung panel (after taking out the Samsung ones)
3.- Test the Dell Monitor with the Samsung Panel

** I have to swap the lamps because the connectors are different (narrow in the Dell, Wide on the Dell). That wa, I'll end up with just a dead monitor instead of two.

With terminal failure you mean "beyond repair, throw it away"?. I've been keeping that screen (and have another from an eMachines e15t3g in the same condition) and I really need to make room, so if that's the case, let me know to take out the lamps and trash the panels.
EGuevarae is offline   Reply With Quote
Old 01-22-2009, 09:20 AM   #20
Wizard
Badcaps Veteran
 
Join Date: Mar 2008
Posts: 2,297
Default Re: DELL E171FP White screen only.

Well, if you can carefully lay out the loose board on the cut up cereal box cardboard against shorts on the LCD panel's and uncover the line driver board (LCD has metal shield with real small screws and find all the power traces around LCD panel's onboard DC to DC converters and measure against ground and you should get several different volts and one of them that can cause white LCD is missing voltage or wrong.

Be gingerly with handling the LCD driver board, flex ribbons are bonded to this and easy to damage. Took pic, will put it up on website after work to show what I mean.

Cheers, Wizard
Wizard is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:00 PM.


Badcaps.net Technical Forums 2003 - 2014
Powered by vBulletin ®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.

Did you find this forum helpful?