Re: LG 60LB7100 screen goes black seconds after start up
I'm guessing nobody else has any ideas?
tstew
Member
Last Activity: 06-16-2017, 03:24 PM
Joined: 05-16-2017
Location: GRAND JUNCTION
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Re: LG 60LB7100 screen goes black seconds after start up
I tested all 12 EL from left to right and the first reading is with back lights on the second reading is 15-20sec after back lights off.
EL62-13.1v to,6.1
EL54-12.9v to 6.1
EL55-13.0v to 5.5
EL64-12.9v to 5.3
EL52-12.9v to 5.4
EL66-12.8v to 5.3
EL65-13.0v to 5.3
EL53-12.9v to 5.3
EL63-13.3v to 5.7
EL50-13.2v to 5.7
EL67-12.0v to 8.8
EL51-12.0v to 8.9Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
LED+ 78.6v down to 55.9v after back lights off.
VC1_13.5v down to 6.0v
VC2_13.1v to 6.0v
VC3_12.1v to 9.3v
VC4_12.9v to 5.7v
VC5_13.0v to 6.0v
VC6_13.0v to 5.9v
Please note that I have no prior experience with testing. Hopefully I had the correct meter setting and test spots this time. I am grateful for everyone who's helping me through this. I tested all of these results twice to make sure they didn't deviate.Last edited by tstew; 06-02-2017, 05:06 PM.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
sean0118. Thank you for explaining that. I had to magnify the picture of my board to see that. I'll be re testing after a while now that I know exactly where to test the VC. I'll post results soon.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I tested resistance from LED+ to each VC+ and got 0.00. then I tested LED+ to each VC- and got 46.7 and 46.6 through out all 6 VC's. Maybe I'm testing wrong with meter setting? My experience with anything electrical is mostly from competition car audio and minor computer upgrades. So this is my first go on trying to save an 1,800 dollar TV.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I'm running out of time to send the inverter board back if this isn't a back light problem.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I kept it in a screw hole right above the board. I'm assuming it's the chassis. The screw hole is in the big sheet metal backing of the screen that all boards attach to.Last edited by tstew; 05-31-2017, 03:49 PM.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
Here's a picture of the meter setting I'm using and the other picture is from the old board but shows where I tested the LED+ and the plug to the left I tested all 1-6 VC's positive. Results were LED+ 78.7v and 55.8v after the lights were off. All 1-6 VC were the same 78.6v down to 55.9v. Maybe I'm testing the wrong spots for VC?...Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I tested the meter on my truck battery and got 12.2 so I believe I have the correct setting. The LED+ and all the VC 1-6 were at 78.6 on start up.Last edited by tstew; 05-29-2017, 01:19 PM.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
budm I did leave the meter ground to the chassis and put the positive to each positive side of both LED+ VC+. I'm kinda thinking the back lights are good. Uncertain though. Waiting for your knowledge on this.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
LED+78.6 all the VC we're the same as before.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
These two pins for LED+ and LED-?...Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
It stayed on until I pulled power from it. That was during testing vc1 with probe to negative/black wire side of pin. When I gave it power again the back lights went off after a few seconds. I two questions before I test again. Of the two pins marked LED+ and LED- the one on the far right is negative, the left pin is positive. Which pin do I test? Also when you say return on the VC testing do you mean test the negative/black wire pin side? I'm grateful for your help. I'm sorry if this is frustrating teaching me. I won't be...Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
On first test I tried putting meter to negative of VC1 thinking that's what you meant by return side. All back lights stayed on until I unplugged and tried again.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I'm testing on the plug pins from the board that go to the ribbons. Also I'm testing the positive of the VC. Maybe I'm testing the wrong spot or wrong setting with my meter? I'm not skilled at this.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
I'm using a klein meter. not a fluke by any measure.
LED+76.7v
after lights off 55.8v
VC_1=78.6v
=55.9
VC_27=78.6
=55.9
All of the other four had exact same readings. I was testing the red positive.Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
Here's a few pics....Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
My question is why will the back lights come on and then go off if any are bad? Wouldn't a bad back light just not come on at all?Leave a comment:
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Re: LG 60LB7100 screen goes black seconds after start up
LED strips ahg. Not easy to replace or find online.Leave a comment:
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LG 60LB7100 screen goes black seconds after start up
TV was fine for two years and one day it just goes black and still has sound. I kept trying to turn it off and on most the day with no luck. The next day I turn it on and it worked fine for another month. Then it did it again. I did the flashlight test and could see the source playing in the screen. When I first turn it on it has full back lights come on with the LG life is good coming on like normal then it just goes black. I purchased a power supply with LED inverter built in and put it in. It's still doing the same thing. On start up it does fine for a few seconds and then goes black while...
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