Hello,
I am currently troubleshooting an LG 60UH8500 TV (2016 TV). Any help or suggestions would be appreciated.
Overall Issue: When TV is turned on, backlights all come on for about 10 seconds, then all go out. There is sound and there is a picture on the display (obviously hard to see without backlights, but it is there).
What I Have Done So Far: 1) Removed the back TV cover to expose the boards (Power Supply, Tcon, and Main), 2) blew out any dust and cleaned all connections, 3) Noticed that the LED backlights are fed from two separate connectors (one is BLK and the other is WHT) from the Power Supply Board (BLK corresponds to the LEFT side lights facing the back of the TV, WHT corresponds to the RIGHT side lights facing the back of the TV for convention). So I disconnected each one, one at a time and tried to power it up. With the BLK connector connected and WHT connector disconnected, the TV powered up fine, the LEFT (corresponding to the BLK connector) backlights turned on fine and stayed on. Basically, a normal TV with the RIGHT half of the backlights out (expected, since I had the RIGHT (WHT) half of the backlights intentionally disconnected). Then I switched the connectors so that the BLK one was disconnected and the WHT one was connected. Powered it on and saw RIGHT backlights come on briefly and then go out (obviously the LEFT backlights never came on since they were disconnected).
This all leads me to believe that there are bad LED(s) on the RIGHT half associated with this WHT connector.
I really, really, do not want to disassemble the TV so I bought a Power Supply Board off of EBay, and swapped the board out. Same exact issue, so this did not help.
One thing I did notice is that with both BLK and WHT connectors connected during the startup is that the Power Supply Board LD701 (which I think is a troubleshooting LED) blinks 4 times periodically. I think this is an error code. But, for the life of me, I cannot find the code matrix for this anywhere on the internet. I know when I have one of the connectors disconnected, this LD701 blinks 3 times periodically so I'm guessing 3 blinks = open LED circuit. But what does 4 blinks mean?
I think I am pretty much into an LED strip replacement, but am in denial since that is such a painful process.
For completeness, there are LED+/- test terminals on the Power Supply Board so I measured this voltage during the three main scenarios:
1) Both BLK (LEFT) and WHT (RIGHT) LED connectors connected, powering on: LED+/- voltage rises from a standby 43 VDC to around 100 VDC, all backlights come on for around 10 seconds, voltage decays to around 63V, all backlights go out, error LED (LD701) blinks 4 times periodically.
2) BLK (LEFT) LED connector connected, WHT (RIGHT) LED connector disconnected, powering on: LED +/- voltage rises from a standby voltage of 43 VDC to around 100 VDC, LEFT backlights all come on and stay on, voltage decays to around 80 VDC, error LED (LD701) blinks 3 times periodically (probably because I have the WHT connector disconnected and it detects an LED open circuit).
3) BLK (LEFT) LED connector disconnected, WHT (RIGHT) LED connector connected, powering on: LED +/- voltage rises from a standby voltage of 43 VDC to around 100 VDC, RIGHT backlights all come on for about 10 seconds and then go off, voltage decays to around 63 VDC, error LED (LD701) blinks 4 times periodically.
I do have an LED tester and I will be testing LED lights as best I can before disassembly.
My biggest questions really are:
1) Shake me out of denial and agree this is a bad LED(s) on the WHT (RIGHT) side somewhere,
2) Does anybody have or know where the LG Power Supply Board troubleshooting LED LD701 decoder matrix is for the number of blinks corresponding to the detected problem? I mean, specifically what does 4 blinks mean!!!???
I am currently troubleshooting an LG 60UH8500 TV (2016 TV). Any help or suggestions would be appreciated.
Overall Issue: When TV is turned on, backlights all come on for about 10 seconds, then all go out. There is sound and there is a picture on the display (obviously hard to see without backlights, but it is there).
What I Have Done So Far: 1) Removed the back TV cover to expose the boards (Power Supply, Tcon, and Main), 2) blew out any dust and cleaned all connections, 3) Noticed that the LED backlights are fed from two separate connectors (one is BLK and the other is WHT) from the Power Supply Board (BLK corresponds to the LEFT side lights facing the back of the TV, WHT corresponds to the RIGHT side lights facing the back of the TV for convention). So I disconnected each one, one at a time and tried to power it up. With the BLK connector connected and WHT connector disconnected, the TV powered up fine, the LEFT (corresponding to the BLK connector) backlights turned on fine and stayed on. Basically, a normal TV with the RIGHT half of the backlights out (expected, since I had the RIGHT (WHT) half of the backlights intentionally disconnected). Then I switched the connectors so that the BLK one was disconnected and the WHT one was connected. Powered it on and saw RIGHT backlights come on briefly and then go out (obviously the LEFT backlights never came on since they were disconnected).
This all leads me to believe that there are bad LED(s) on the RIGHT half associated with this WHT connector.
I really, really, do not want to disassemble the TV so I bought a Power Supply Board off of EBay, and swapped the board out. Same exact issue, so this did not help.
One thing I did notice is that with both BLK and WHT connectors connected during the startup is that the Power Supply Board LD701 (which I think is a troubleshooting LED) blinks 4 times periodically. I think this is an error code. But, for the life of me, I cannot find the code matrix for this anywhere on the internet. I know when I have one of the connectors disconnected, this LD701 blinks 3 times periodically so I'm guessing 3 blinks = open LED circuit. But what does 4 blinks mean?
I think I am pretty much into an LED strip replacement, but am in denial since that is such a painful process.
For completeness, there are LED+/- test terminals on the Power Supply Board so I measured this voltage during the three main scenarios:
1) Both BLK (LEFT) and WHT (RIGHT) LED connectors connected, powering on: LED+/- voltage rises from a standby 43 VDC to around 100 VDC, all backlights come on for around 10 seconds, voltage decays to around 63V, all backlights go out, error LED (LD701) blinks 4 times periodically.
2) BLK (LEFT) LED connector connected, WHT (RIGHT) LED connector disconnected, powering on: LED +/- voltage rises from a standby voltage of 43 VDC to around 100 VDC, LEFT backlights all come on and stay on, voltage decays to around 80 VDC, error LED (LD701) blinks 3 times periodically (probably because I have the WHT connector disconnected and it detects an LED open circuit).
3) BLK (LEFT) LED connector disconnected, WHT (RIGHT) LED connector connected, powering on: LED +/- voltage rises from a standby voltage of 43 VDC to around 100 VDC, RIGHT backlights all come on for about 10 seconds and then go off, voltage decays to around 63 VDC, error LED (LD701) blinks 4 times periodically.
I do have an LED tester and I will be testing LED lights as best I can before disassembly.
My biggest questions really are:
1) Shake me out of denial and agree this is a bad LED(s) on the WHT (RIGHT) side somewhere,
2) Does anybody have or know where the LG Power Supply Board troubleshooting LED LD701 decoder matrix is for the number of blinks corresponding to the detected problem? I mean, specifically what does 4 blinks mean!!!???
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