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 02-27-2010, 05:43 PM   #1
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Dell E196FPf

Hi all, this will be my first attempt at repairing an LCD monitor.
I haven't done much repair work in a long time, so I'm dusting off my gear and hoping for the best.
Equipment available:
My old trusty Fluke 77 DMM, Capacitor Wizard ESR meter, Hitachi scope, and a Blue ring tester is on it's way soon.

Monitor is a Dell E196FPf no backlight. Image is visible on the monitor with a flashlight so I suspect just the inverter, or maybe a bad lamp, though none of the 4 come on at all, even at power up.

2 caps in the inverter section are bulged and have relatively high ESR (2 ohms) other than that no obvious visible signs. Solder joints on the transformers look ok, I'll re-do them though.
I don't see anything that looks like a fuse so far. While I wait for caps, I'll look up some part numbers and test some of the transistors if I can.
Photos are full board, and closeups of the inverter section.
Has anyone worked on this model before?
Attached Images
File Type: jpg IMG_6584a.jpg (204.6 KB, 168 views)
File Type: jpg IMG_6599a.jpg (177.5 KB, 106 views)
File Type: jpg IMG_6605a.jpg (221.5 KB, 95 views)
File Type: jpg IMG_6617a.jpg (279.7 KB, 79 views)
smason is offline   Reply With Quote
Old 02-27-2010, 07:18 PM   #2
PlainBill
Badcaps Veteran
 
PlainBill's Avatar
 
Join Date: Feb 2009
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist
Posts: 7,013
Default Re: Dell E196FPf

Quote:
Originally Posted by smason
Hi all, this will be my first attempt at repairing an LCD monitor.
I haven't done much repair work in a long time, so I'm dusting off my gear and hoping for the best.
Equipment available:
My old trusty Fluke 77 DMM, Capacitor Wizard ESR meter, Hitachi scope, and a Blue ring tester is on it's way soon.

Monitor is a Dell E196FPf no backlight. Image is visible on the monitor with a flashlight so I suspect just the inverter, or maybe a bad lamp, though none of the 4 come on at all, even at power up.

2 caps in the inverter section are bulged and have relatively high ESR (2 ohms) other than that no obvious visible signs. Solder joints on the transformers look ok, I'll re-do them though.
I don't see anything that looks like a fuse so far. While I wait for caps, I'll look up some part numbers and test some of the transistors if I can.
Photos are full board, and closeups of the inverter section.
Has anyone worked on this model before?
I believe someone has posted pictures of this (or a similar) combination power supply / inverter / logic board. Or at least something similar to it. A couple of points to check:

U1 in the inverter section - I believe that is the inverter controller. Look for the datasheet.

There should be two signal traces from the logic board portion over to the inverter portion.

Larger pictures of both front and back of the circuit board would help.

PlainBill
__________________
For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.
PlainBill is offline   Reply With Quote
Old 03-01-2010, 08:13 PM   #3
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf

Quote:
Originally Posted by PlainBill
Larger pictures of both front and back of the circuit board would help.

PlainBill
Thanks for the reply. I'll try to post bigger photos tomorrow.
I was tempted to get some caps locally (not likely to find good ones here) but sat down and had a beer and the feeling passed

In the mean time my trusty Fluke 77 has flaked out on me, so fixing that while waiting for caps. It doesn't look good, corrosive liquid damage (have no idea what, may have come from a cat...) between the board and the display elastomer. Ugh...
smason is offline   Reply With Quote
Old 03-01-2010, 08:52 PM   #4
PlainBill
Badcaps Veteran
 
PlainBill's Avatar
 
Join Date: Feb 2009
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist
Posts: 7,013
Default Re: Dell E196FPf

Quote:
Originally Posted by smason
Thanks for the reply. I'll try to post bigger photos tomorrow.
I was tempted to get some caps locally (not likely to find good ones here) but sat down and had a beer and the feeling passed

In the mean time my trusty Fluke 77 has flaked out on me, so fixing that while waiting for caps. It doesn't look good, corrosive liquid damage (have no idea what, may have come from a cat...) between the board and the display elastomer. Ugh...
I had a similar problem with a cat and some electronics. I sat the cat down and explained about stringing tennis rackets.

It didn't help. Cats DO NOT take suggestions.

PlainBill
PlainBill is offline   Reply With Quote
Old 03-02-2010, 10:59 AM   #5
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf

LOL I had the same conversation about tennis rackets.
He muttered something about nylon, and how for a techie, I'm "surprisingly not up to speed on modern polymers", then walked away....
smason is offline   Reply With Quote
Old 03-04-2010, 07:58 PM   #6
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf Good News

Well I'm happy to report that my Fluke 77 survived minor surgery (cleaned the pcb, scraped off the residue from the stuck on elastomer, then tinned the pads as the copper was in bad shape) cleaned the elastomer with isopropyl and a pec pad. re-assembled and to my surprise it works beautifully!
I was so optimistic, I had bids on 2 77s on Ebay

Also the caps for the Dell monitor came in yesterday, and I replaced the 2 bad ones with Panny FMs. Checked the FETs and measured the transformers, all seemed fine.

Just for grins I decided to try it, though I suspected there was more to do, and whaddaya ya know? It works!
I'll leave it on test for a while, then give it back to the owner and tell him he owes me $0.66 for parts.
smason is offline   Reply With Quote
Old 03-04-2010, 08:32 PM   #7
PlainBill
Badcaps Veteran
 
PlainBill's Avatar
 
Join Date: Feb 2009
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist
Posts: 7,013
Default Re: Dell E196FPf Good News

Quote:
Originally Posted by smason
Well I'm happy to report that my Fluke 77 survived minor surgery (cleaned the pcb, scraped off the residue from the stuck on elastomer, then tinned the pads as the copper was in bad shape) cleaned the elastomer with isopropyl and a pec pad. re-assembled and to my surprise it works beautifully!
I was so optimistic, I had bids on 2 77s on Ebay

Also the caps for the Dell monitor came in yesterday, and I replaced the 2 bad ones with Panny FMs. Checked the FETs and measured the transformers, all seemed fine.

Just for grins I decided to try it, though I suspected there was more to do, and whaddaya ya know? It works!
I'll leave it on test for a while, then give it back to the owner and tell him he owes me $0.66 for parts.
You undervalue yourself. I always mark up parts 20% for my warranty and 10000% for knowing which parts to replace.

PlainBill
PlainBill is offline   Reply With Quote
Old 03-04-2010, 08:37 PM   #8
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf Good News

Quote:
Originally Posted by PlainBill
You undervalue yourself. I always mark up parts 20% for my warranty and 10000% for knowing which parts to replace.

PlainBill
Yeah, I agree, but this "customer" is a co-worker who gave me a $50.00 gift certificate to my fave restaurant for doing a minor tune-up on his computer last month (which I did on company time ) and another $50.00 last year for a virus removal job, so I don't think he owes me on this one.

Besides this was a learning experience for me, and my first real repair in quite a while.
smason is offline   Reply With Quote
Old 03-28-2010, 12:29 PM   #9
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf Good News

Did you replace the parts that are rectangular and about 1"x 3/4"labeled SPW-504 amd TDK0545X. Also where did you order them online.
garbermf is offline   Reply With Quote
Old 03-28-2010, 01:31 PM   #10
Bobdee
Badcaps Veteran
 
Join Date: Jun 2008
City & State: WALES UK
Posts: 461
Default Re: Dell E196FPf Good News

Quote:
Originally Posted by garbermf
Did you replace the parts that are rectangular and about 1"x 3/4"labeled SPW-504 amd TDK0545X. Also where did you order them online.
The parts you mention are Inverter Transformers
It may help contacting
http://www.lcdrepair.us/
By email I think they may help
Bobdee is offline   Reply With Quote
Old 03-28-2010, 03:10 PM   #11
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf Good News

Quote:
Originally Posted by garbermf
Did you replace the parts that are rectangular and about 1"x 3/4"labeled SPW-504 amd TDK0545X. Also where did you order them online.
I only replaced the 2 caps, the ones between the transformers. They were slightly bulging, but hard to see at the angle of that photo. I ordered Panasonic FM capacitors from Digikey.ca

I doubt the "bulging" of the transformers is an issue. They usually fail quite silently.

What are the symptoms of your monitor?
smason is offline   Reply With Quote
Old 03-28-2010, 06:48 PM   #12
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

It does not show any signs of power. I did try an ohm meter on both fuse blocks and did not get any continuity. Is this an accurate test on these types of fuses?
garbermf is offline   Reply With Quote
Old 03-28-2010, 07:54 PM   #13
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf

Quote:
Originally Posted by garbermf
It does not show any signs of power. I did try an ohm meter on both fuse blocks and did not get any continuity. Is this an accurate test on these types of fuses?
Yes an ohmmeter should be an accurate test of a fuse.
If you post some photos, and point out what/where you tested, we can try to help some more.
smason is offline   Reply With Quote
Old 03-29-2010, 07:51 PM   #14
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

I was testing the two white boxes with an ohm meter. I marked them with red circles with an "X" where the pins are on the back side of the board. I thought these were the fuses.
garbermf is offline   Reply With Quote
Old 03-29-2010, 08:06 PM   #15
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

Sorry I had to reduce the size of my attachment.
Attached Images
File Type: jpg E196fpf.jpg (427.2 KB, 95 views)
garbermf is offline   Reply With Quote
Old 03-29-2010, 08:14 PM   #16
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Dell E196FPf

Quote:
Originally Posted by garbermf
I was testing the two white boxes with an ohm meter. I marked them with red circles with an "X" where the pins are on the back side of the board. I thought these were the fuses.

I don't think those are fuses, they're labelled as caps.

The fuse appears to be the round black component that has the amp and voltage rating on it.
smason is offline   Reply With Quote
Old 03-29-2010, 08:29 PM   #17
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

I found the fuse and it was labeled F850. I tested it and it has continuity.
garbermf is offline   Reply With Quote
Old 03-29-2010, 10:02 PM   #18
PlainBill
Badcaps Veteran
 
PlainBill's Avatar
 
Join Date: Feb 2009
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist
Posts: 7,013
Default Re: Dell E196FPf

Quote:
Originally Posted by garbermf
I found the fuse and it was labeled F850. I tested it and it has continuity.
"No sign of power" isn't very specific. Have you checked for voltage out of the power supply? Across the leads of the big cap? As has already been suggested, good pictures of the power supply section would be a good way to help us help you.

PlainBill
PlainBill is offline   Reply With Quote
Old 04-01-2010, 05:09 PM   #19
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

Sorry for the delay and thank you for your help.

I measured across the big blue cap and got 368V (ACV).
Attached Images
File Type: jpg E196fpf power.jpg (391.6 KB, 51 views)
garbermf is offline   Reply With Quote
Old 04-01-2010, 05:19 PM   #20
garbermf
New Member
 
Join Date: Mar 2010
Posts: 12
Default Re: Dell E196FPf

PlainBill,
Do you want me to post any pictures back side of the board?
garbermf 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 01:17 PM.


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