Re: LG 60LB7100 screen goes black seconds after start up
LED+78.6 all the VC we're the same as before.
LED+78.6 all the VC we're the same as before.
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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.Comment
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Last edited by budm; 05-28-2017, 10:16 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LG 60LB7100 screen goes black seconds after start up
Are you sure that the multimeter is working and the DC voltage setting is selected?
If your unsure, confirm by measuring the voltage of a 9V battery or similar.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.Comment
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Re: LG 60LB7100 screen goes black seconds after start up
I've attached a circuit based on budm's description (I might be wrong).
Each LED represent 100 or so in series, so the voltage at VC_1 is LED+ minus the voltage drop over the first string of LEDs. So it must be less than LED+ unless something is horribly wrong...Attached FilesComment
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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?Attached FilesComment
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Re: LG 60LB7100 screen goes black seconds after start up
Where did you put the black probe of the meter?Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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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.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.Comment
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Re: LG 60LB7100 screen goes black seconds after start up
Interesting... sounds like you're doing it right. What's the resistance (when OFF) from LED+ to each VC?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.Comment
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Re: LG 60LB7100 screen goes black seconds after start up
I might be missing something, but there is no VC+ and VC-, only VC, which is the cathode voltage of the LEDs. LED+ is the anode voltage. The pins of that 14pin connector alternate between LED+ and each of the six VC lines.Comment
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Re: LG 60LB7100 screen goes black seconds after start up
Damn! Seems that LED tvs are no better than CCFL tvs from the Core 2 era.....(also that was the classic bad cap tv era) (2006-2009)Last edited by RJARRRPCGP; 06-02-2017, 09:49 AM.ASRock B550 PG Velocita
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eVGA Supernova G3 750W
Western Digital Black SN850 1TB NVMe SSD
Alienware AW3423DWF OLED
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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.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.Comment
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Re: LG 60LB7100 screen goes black seconds after start up
Sounds like your on the right track now, but unfortunately I don't know much about this TV, so you'll have to wait for one of the pros to chime in with instructions.
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Re: LG 60LB7100 screen goes black seconds after start up
What voltages do you have on the EL test pointsAttached FilesWilling to help but I'm no expert.Comment
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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 8.9Comment
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