So is there a good explanation of why a single segments can have varying brightness as in the OP's pic? Nice fix by the way OP and others who followed the advice - it is so nice to see some of these items get repaired and not thrown away.
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Yea I see what you mean, I wasn't looking at the link correctly. However, it may look the same but it wouldn't be an LED in series with the other 7 LEDS.
The nomenclature "W1" should mean something to someone, but I have never heard of a "W" as a reference designator for a particular device.
It does look like the bottom of those, but there is no color on the top of this "W1" so I am thinking not an LED. I am more inclined to think a protection device either a fuse or something similar.
I am thinking along the lines of Samsung has had their share of fires so perhaps engineering across the board incorporated some safety features.
It's nice to see the zener diodes there also (i think) so if you lose one LED you don't lose the whole TV.
Working a Samsung UN32M530DAFXZA no backlight, flashlight test OK - manufacturing date July 2017.
When evaluating the LED strips with the low current tester one strip fluctuates a bit going from about 18.3 volts to 23 volts. I suspect this is the strip causing the shutdown.
After pulling the screen and looking at them, it looks like the part labeled "W1" is the problem. On the good strip it measures a short. On the questionable strip it seems to check like a diode?
The part next to it appears to be a zener diode and there is one for each LED,...
Not reading back through everything but if you still have the TCON connected to the buffer boards a short on one board will appear on the other. You need to disconnect the TCON and see if you only have shorted capacitors on the left or right buffer board.
Re: Sharp LC- 58Q620U - Standby Light, No Backlights or Image
A single red vertical line is most likely a bad panel, or more precisely the COF is defective and that column is kept in a constant on state. You will likely have to live with it or part the TV out.
Seems a bit odd. So the 12.95V is from the JP822 jumper to chassis ground? You stated earlier referenced to the 0V pin on main connector, which I suppose could be chassis ground but that needs to be verified. Also, if the cable is unplugged you can't be using that point of reference in this second measurement.
Power On 0V? With Samsung I believe all the commands should float high when the Main is disconnected. So just to be sure that Power On you are measuring is pin 8 on CNM0801 to chassis ground?...
With Samsung models you should be able to test the Power Supply / Backlights by disconnecting the interconnect cable between the Main board and Power Supply. The backlights should come on when power is applied if the Power Supply and LED's are operational.Re: Samsung UN70NU6900FXZA PSU failu...s many of that...
I just did the Samsung UN60D6000SF and it was very stressful. What had happened was on all four sides the thin rubber strips that support the panel and should only have adhesive on one side only stuck to both the panel and the panel supports. I had to use a thin piece of mylar to break it free. The top and the sides were not too bad - carefully hold the COF up on the sides when you do that in case you get a sudden release.
As for the bottom it was the worst as the buffer boards had to be rolled back and then very carefully work...
Well it took a while but I finally tore this thing down - it weighs a ton so I had been avoiding it.
Anyway, the video defect was nothing more than a smudge on the light guide. After removing the panel and powering the LED's on it was very visible. It was less visible with the diffuser sheets pulled up but still obviously there. I could barely see the smudge when viewing the light guide from an angle with the LED's off.
I simply wiped the spot with some isopropyl alcohol and all was well. And, just to duplicate...
Re: Sony XBR-43x800e TV had sudden loss of picture
I just did one on a Samsung 60 inch and tried the low resistance method, which I have had good success with before. Unfortunately this time no luck.
I then took a variable power supply and connected it across the shorted caps and adjusted the voltage until the current meter read 250 mA. If I then had a FLIR camera it would have easily found the shorted cap, but I was able to use my pinky finger (most sensitive) and feel the warmth in the one that was shorted after about 1 min.
Re: UN55D6900 BN44-00428B partial led driver circuit failure
So just to be sure when you say bottom of the diode and top of the diode where are you probing - is that like Dxx51 anode / cathode? And just to be sure that is in respect to chassis ground?
222V sounds scary, particularly if the LED's seem brighter. If they were probed at the 801A and 801B connectors just like when you hook up the LED tester (R3+ to L3-) then that would be a more exact measurement of the voltage drop across the string. I am thinking anything over about 170 VDC I would shut...
Re: UN55D6900 BN44-00428B partial led driver circuit failure
So no voltage across R9265 suggests an open in the LED circuit, or a problem on the low side as R_J suggested earlier. You already verified boost voltage is working on that section, but perhaps rechecking boost since you swapped IC's might be in order.
Are you working with the TV open and just the Power Supply connected - no main?
If open, does that suspect circuit flash the LED's and subsequently produce a momentary voltage across R9265 when first powered up?
I would suspect shipping the light guide would not be cost effective, the diffuser sheets could be rolled up and shipped at a fairly reasonable price, but the hard plastic light guide might be too costly.
I just tore down a Samsung UN50NU6900 that had a busted screen, but the busted screen was a result of someone read that hitting the side of the TV could remedy failed LED's.
Anyway, it has a couple of burn marks on the light guide from the bad LED's, but I also noticed the guide is cut differently on the bottom...
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