So, I fixed a 47" Seiki last week, just a couple bad LED strips and I had a complete set so it cost me nothing but the $10 I gave my friend for it, but it ended up having about 20 dead pixels. Not a row, just a group in one area and a few scattered around that area. This has me wondering what actually causes a dead pixel. I mean, is it the actual pixel which is dead, could it be a bad COF, or could it be something on one of the driver boards. Maybe the question is why are they dead, or where are they dead.
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Re: What causes dead pixels?
I had a Samsung LCD 46 inch from 2005 A few weeks ago that developed quadrants of blue pixels. I believe that this is a pressure related problem. The screen has got pressed in that section to the point where I did not crack but caused significant damage it within the pixels. The TFT part of the LCD panel.Did I leave the soldering iron on? -
Re: What causes dead pixels?
That's what I was leaning towards. Thanks.------------signature starts here------------
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Re: What causes dead pixels?
Two things come to mind when doing a backlight repair that could cause this. When your pulling the panel and releasing the address buffer boards from the holders be careful not to damage them or the ribbon cables connected to the panel. Also if your using suction cups to lift the panel use lightweight suction cups and release them as soon as panel is secure or while waiting to install the new led's.Comment
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Re: What causes dead pixels?
I didn't have suction cups at that time. I used to use plastic swipe cards to carefully get under the panel and then lift it out. I picked up a pair of cups designed for ceramic tile work at Home Depot after that one because I had a 50" to do and the bigger screens are harder to get out alone without them. I was wondering about the amount of suction they apply (12lbs each). I'm certain the screen was damaged before I got it (this time, lol).Originally posted by brucetv View Post------------signature starts here------------
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Re: What causes dead pixels?
Dead pixels are a failure inside the TFT glass itself, not COF/tab bond related, those can only cause lines. Could be caused by pressure or they could have been there from the get go - the set had no backlight when you got it so there was no way you could have known.A working TV? How boring!Originally posted by PeteS in CAComment
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Re: What causes dead pixels?
I was thinking it would have been in the glass, but then since they were black I was thinking perhaps they weren't being switched on. It was otherwise a perfect TV. I still had a good week with 2 fixed plasmas, 2 LED fixed(counting the dead pixel one), and one where I soldered a coax connector back on for a friend who in turn gave me a 40" RCA with a dead power supply(and I have a working one in a box somewhere with a broken corner).------------signature starts here------------
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Re: What causes dead pixels?
A few things
Pressure/impact can destroy the TFTs or sever the connections to them
Contamination during manufacture
Yield issues during manufacture
UV light damage (responsible for the failure of some LCD panels from their own backlight), also can be caused by sunlightPlease do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: What causes dead pixels?
Is it just me, or were LCDs per-se, getting much better, since sometime in 2008??? It seemed that back in a chunk of the socket 775 era, broken pixels were alarmingly common! Then in 2008 and 2009, it seemed possibly common that you needed to massage a pixel out, due to being stuck...Last edited by RJARRRPCGP; 03-08-2018, 09:40 AM.ASRock B550 PG Velocita
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Re: What causes dead pixels?
LCD manufacturing processes have improved year on year, it's improvements in yield and reductions in the cost of manufacture that has driven the prices down greatly. It's also why you see a lot more Chinese panels, as they can now reliably produce them and compete in the market with the more established players.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: What causes dead pixels?
Stuck pixels or small crack on top left of Samsung 50 inch led tv?Attached FilesYou live and you learn right?
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Re: What causes dead pixels?
That's a crack. No question about it.Originally posted by Gdog215 View Post------------signature starts here------------
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Re: What causes dead pixels?
All the parts were covered in tarry dust. Clearly a chain smoker' s TV. So, I think maybe the pixels died from second hand smoke.------------signature starts here------------
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Re: What causes dead pixels?
Damn was a nice Sammy 50 inch led with no power no standby light paid $25.00
Ordered a new ps for 12 bucks, this morning disconnected mb from pb, Backlights worked saw what looked like stuck pixels on 1.5 inches top right screen. The rest of the screen looked good. You live you learnYou live and you learn right?Comment
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