Hoping for some help diagnosing the problem with my TV so I don't just throw parts at it or the land fill. Its an LG 50UH5530, that after being unplugged for a few hours it will turn on and stay on for about 15 seconds, before shutting off. After that, when pressing the power button the red led will blink but the TV will not turn on. I have read the folllowing post that discribe very similar symptoms and followed the steps documented.
https://www.badcaps.net/forum/showthread.php?t=87284
Current Status:
STB pin on power board has 3.4v, always.
13.2 pin on power board have 6-9v
When first turning on before TV shuts down, 13.2 pins have 13.1-13.2 volts
When jumping STB with resistor 13.2v pins have 13.1-13.2 volts
When testing led strips with tester, all strips light up when viewing from the back of the tv and run at about 66v. I can't see the individual led since I have not remove the panel
When turning on with the led strip disconnected same thing happens
When turing on with TCON disconnected same thin happens
With the flashlight test is appear the LCD is not on, so it's more then just back light
The OP in the other thread eventaully replaced the led strips and resolved his problem. I have also read on Shop Jimmy that led failures are much more common then power board failures on this model.
So I can throw led strips at it but I'm hoping to confirm a diagnoses first. My concern is it appears that the main board is instructing the power board to shutdown, so either it's detecting some fault or the main board is faulty and shutting down.
I'm looking for suggestions to help me diagnoses the failure.
I have some expereince with hardware so I have good amount of tools, but I am far from an expert.
TV Background:
I picked up the TV off Nextdoor app. Two of the three HDMI ports had come off the mainboard, the original owner said it was like that for awhile and still worked. I resoldered one back on, the other the pins where too bent to resolder. If I can get the TV working and find the ports on DigiKey I'll resolder the remaining missing port later. The 3rd HDMI port that wasn't disconnected was loose, upon closer examination there was no solder on the mounting pins of the port, the only thing holding the port where the pins. The pads where not damaged, and I believe the original owner that the TV worked for quite a while like this so I don't think its related to the failure.
Thanks
John
https://www.badcaps.net/forum/showthread.php?t=87284
Current Status:
STB pin on power board has 3.4v, always.
13.2 pin on power board have 6-9v
When first turning on before TV shuts down, 13.2 pins have 13.1-13.2 volts
When jumping STB with resistor 13.2v pins have 13.1-13.2 volts
When testing led strips with tester, all strips light up when viewing from the back of the tv and run at about 66v. I can't see the individual led since I have not remove the panel
When turning on with the led strip disconnected same thing happens
When turing on with TCON disconnected same thin happens
With the flashlight test is appear the LCD is not on, so it's more then just back light
The OP in the other thread eventaully replaced the led strips and resolved his problem. I have also read on Shop Jimmy that led failures are much more common then power board failures on this model.
So I can throw led strips at it but I'm hoping to confirm a diagnoses first. My concern is it appears that the main board is instructing the power board to shutdown, so either it's detecting some fault or the main board is faulty and shutting down.
I'm looking for suggestions to help me diagnoses the failure.
I have some expereince with hardware so I have good amount of tools, but I am far from an expert.
TV Background:
I picked up the TV off Nextdoor app. Two of the three HDMI ports had come off the mainboard, the original owner said it was like that for awhile and still worked. I resoldered one back on, the other the pins where too bent to resolder. If I can get the TV working and find the ports on DigiKey I'll resolder the remaining missing port later. The 3rd HDMI port that wasn't disconnected was loose, upon closer examination there was no solder on the mounting pins of the port, the only thing holding the port where the pins. The pads where not damaged, and I believe the original owner that the TV worked for quite a while like this so I don't think its related to the failure.
Thanks
John
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