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#1 |
Member
Join Date: Sep 2013
City & State: Lubbock, Texas
My Country: US
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 31
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![]() So I have a TV in my bedroom which I was given as a repair job due to a white screen issue. I suspected the T-Con board, but could never get it to replicate the issue after months of use. I gave it back thinking it must be something wrong with his input device, but he kept experiencing the issue so he gave it to me as a freebie. Its been sitting for months in the bedroom unused, until I got a chromecast today and figured I'd start being lazy and watch TV in bed.
Of course, since I decided to use it for personal enjoyment, lo and behold, white screen. Sound works fine, this TV has a built in dvd player and I can hear it going, but all I get is a very bright white screen. Google being my friend I was directed to look into the mainboard to t-con ribbon cable (which I can't seem to re-seat for the life of me) and power supply transistor Q413 and fuse F404. I have attached the readings I get from both in an image, as well as the ribbon cable. It seems to me the voltage on the middle connection of the transistor (I believe is the collector) is far too high, as other posts I read on this issue show readings closer to 1.5V As an aside, when I was checking q413, I believe I shorted a connection somewhere and the TV started working again, until I move my meter probe off what it was touching, and it immediately cut back out. I have not however been able to replicate what I did which made the picture cut back in, as I was watching the screen, and did not see exactly what my probe was touching. I'm still a noob as all of my previous repairs have involved replacing bad caps, or entire main boards/power supply boards. So individual component level details I have no experience with. How does the voltage look, or any other suggestions? |
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#2 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,206
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![]() That is the commonly failed transistor which supplies the Voltage to run the T-CON board.
http://s807.photobucket.com/user/bud...?sort=3&page=1 You can check for cold solder joints on all 3 legs of that transistor.
__________________
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; 12-26-2014 at 01:25 AM.. |
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#3 |
Member
Join Date: Sep 2013
City & State: Lubbock, Texas
My Country: US
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 31
|
![]() Well holy smokes, that seems like that was it. I checked the solder joints and didn't see anything that looked like a cold solder to me, but I sucked the solder away and flowed new solder in its place anyways, and now it's working.
Thanks Budm! |
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#4 |
Member
Join Date: Sep 2013
City & State: Lubbock, Texas
My Country: US
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 31
|
![]() Never mind, its back to white screen tonight.
next idea? |
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