Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting TVs and Video Sources
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 02-09-2021, 10:12 AM   #21
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Smile Re: Samsung LE40A676 takes several minutes to start

Thanks for your advices! I went for the easiest test first, which was just to heat up the main board a bit, using a hair dryer, and then try to start the TV.
That was a success!
After heating up the main board a bit, the TV started up immediately!
Does this brings us back to find the "bad C102" on the main board, or do we suspect something else?
Chrille is offline   Reply With Quote
Old 02-09-2021, 10:43 AM   #22
Davi.p
Badcaps Veteran
 
Davi.p's Avatar
 
Join Date: Sep 2009
City & State: Milan
My Country: Italy
I'm a: Hobbyist Tech
Posts: 1,907
Default Re: Samsung LE40A676 takes several minutes to start

Samsung A500 / A558 series is different from yours so you will not find same cap. Check the ripple on every el.cap. especially those with 3,3v or less on it.
Davi.p is offline   Reply With Quote
Old 02-09-2021, 02:27 PM   #23
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,979
Default Re: Samsung LE40A676 takes several minutes to start

Try isolating parts of the board with a piece of cardboard when you heat parts of the board.
This does not apply directly to your board, but C102 is a filter capacitor for a MP2363 step-down converter ic. It is possible that one of the caps on a similar ic is the problem.

Last edited by R_J; 02-09-2021 at 02:49 PM..
R_J is offline   Reply With Quote
Old 02-10-2021, 04:04 AM   #24
Davi.p
Badcaps Veteran
 
Davi.p's Avatar
 
Join Date: Sep 2009
City & State: Milan
My Country: Italy
I'm a: Hobbyist Tech
Posts: 1,907
Default Re: Samsung LE40A676 takes several minutes to start

With the luck he has of owning an oscilloscope the faster better way is to check ripple..
Davi.p is offline   Reply With Quote
Old 02-10-2021, 01:56 PM   #25
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

By heating the marked area I could make the TV start in a few seconds.
Now I can focus on finding the defective component.
Hope I'll be back soon!
Attached Images
File Type: jpg 20210210_204328.jpg (863.9 KB, 13 views)
Chrille is offline   Reply With Quote
Old 02-10-2021, 02:08 PM   #26
budm
Badcaps Veteran
 
budm's Avatar
 
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,116
Default Re: Samsung LE40A676 takes several minutes to start

Since that area that you heat up has lytics cap (100uF 16VDC), you can try replacing that Cap (LOW ESR type).
Also, what is the designator and what is printed on that black rectangular component to the left of the IC1110?
__________________
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; 02-10-2021 at 02:11 PM..
budm is offline   Reply With Quote
Old 02-10-2021, 02:39 PM   #27
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

The 100uF cap seems to be Ok but there is a MP2363DN (IC1110) that I've read from other threads that can be faulty...
At the moment everything points at IC1110. I took my Hot air soldering station and tried to focus the heat on IC1110 only, and when I did that, the TV started.
I can't say by 100% because some air may affec surounding components but there's a big chans that that's the component to replace!
Then I just have to find a place from where I can buy it...
Attached Images
File Type: jpg 20210210_210447.jpg (1.71 MB, 10 views)

Last edited by Chrille; 02-10-2021 at 03:23 PM..
Chrille is offline   Reply With Quote
Old 02-10-2021, 03:46 PM   #28
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

My last test by heating with a soldering iron gave me the same result so now I'm as shure as you can get!
I found this one: https://www.digikey.com/en/products/...3DN-LF/5299123
But there's a "LF" at the end. Will this be Ok to use?
Chrille is offline   Reply With Quote
Old 02-10-2021, 05:10 PM   #29
Davi.p
Badcaps Veteran
 
Davi.p's Avatar
 
Join Date: Sep 2009
City & State: Milan
My Country: Italy
I'm a: Hobbyist Tech
Posts: 1,907
Default Re: Samsung LE40A676 takes several minutes to start

Quote:
The 100uF cap seems to be Ok
Tested how? YOU MUST BE SURE..
Don't buy that chip, it is almost surely the cap, if you have one even higher capacity and voltage, solder it only for test on top of the old one and test the board. I'm wondering why you have the luck of having an o'scope and you don't use it , and i am 15 years repairing making money save without it.. last but not least.. caps improves with the heat, semicon the opposite..

Last edited by Davi.p; 02-10-2021 at 05:14 PM..
Davi.p is offline   Reply With Quote
Old 02-10-2021, 05:53 PM   #30
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,979
Default Re: Samsung LE40A676 takes several minutes to start

If you don't have a 100f to replace it, just parallel about a 10f ~ 47f across it to see if that helps.
I should add that this is just to test the operation, if this works, the 100f would need to be replaced.

Last edited by R_J; 02-10-2021 at 06:46 PM..
R_J is offline   Reply With Quote
Old 02-11-2021, 02:16 PM   #31
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

Thanks you for your commitment, and I'm sorry for not having mension it but I did try to solder a 33uF cap in parallell to the existing 100uF cap, but it was no difference. I've also measured the existing cap and it looks fine.
When I finally tested to heat the just IC1110 with my soldering iron, I'm quite convinced that this is the one!
I agree that it seems a bit strange, and I would not think that this was the the faulty component either, but at the moment, everything points at that direction.
Chrille is offline   Reply With Quote
Old 02-11-2021, 04:15 PM   #32
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

And here's for you David.p, just to to satisfy your curiosity
The red line is the charging of Cap 1080 when powering on.
Attached Images
File Type: jpg 20210211_230544.jpg (649.6 KB, 12 views)
Chrille is offline   Reply With Quote
Old 02-12-2021, 01:50 PM   #33
Davi.p
Badcaps Veteran
 
Davi.p's Avatar
 
Join Date: Sep 2009
City & State: Milan
My Country: Italy
I'm a: Hobbyist Tech
Posts: 1,907
Default Re: Samsung LE40A676 takes several minutes to start

Try to substitute the cap, maybe it can go short and frees short on warming..
i can't see entire wave form..

Last edited by Davi.p; 02-12-2021 at 01:52 PM..
Davi.p is offline   Reply With Quote
Old 02-16-2021, 02:02 PM   #34
Chrille
Chrille
 
Join Date: Feb 2021
City & State: Skillingaryd
My Country: Sweden
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 21
Default Re: Samsung LE40A676 takes several minutes to start

Hi,
I don't know what you mean with "entire wave form". That's the whole charging cycle. The start is when the TV is off and the end when it's powered on. Nothing more exciting happens later on. If the cap had been bad, I guess there would be a lot of ripple.

Anyway, now to the "solution".
I might be wrong here, but I'm quite convinced that the problem lies on IC1110.
Recently I "fixed" a defective graphic card just by heating it in the owen 15 min in 125 deg C.
I know, I didn't repair the card, but I made it work. Don't know for how long, but it's still working after a week. The two images shows before and after. This was NOT a fix for bad solderings and I'm not going to talk more about that here, but the temperature prove my words.
Since IC1110 is quite tricky to replace, and there's also a risk that I might damage the surounding components, I decided to try the same trick here.
The result was a success so far! I heated up IC1110 with my hot air soldering station (a lot more than before), and now is the TV working!
You might beleive that it's because someting else, and that's Ok. I won't argue about that since it works fine now.
The time will show how long it will work and if the problem comes back, I will take the risk to replace the IC.

But for now: The TV is working -> The problem is solved!
Thanks all for your commitment!
Attached Images
File Type: jpg 20210207_004151.jpg (1.16 MB, 6 views)
File Type: jpg 20210209_192021.jpg (1.22 MB, 6 views)
Chrille is offline   Reply With Quote
Old 02-16-2021, 04:44 PM   #35
Davi.p
Badcaps Veteran
 
Davi.p's Avatar
 
Join Date: Sep 2009
City & State: Milan
My Country: Italy
I'm a: Hobbyist Tech
Posts: 1,907
Default Re: Samsung LE40A676 takes several minutes to start

i did a mistake.
Davi.p 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



Badcaps.net Technical Forums 2003 - 2021
Powered by vBulletin ®
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 05:10 AM.
Did you find this forum helpful?