I have a LG 55LV5500-UA led smart tv that has no picture or sound when powered on. When the tv is turned on it powers on & the lg logo display for a couple of seconds then go off. There is no picture or sound just backlights staying on. I removed the rear cover to check for popped capacitors but there were none. I would appreciate any help.
LG 55LV5500-UA no picture or sound
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Re: LG 55LV5500-UA no picture or sound
"There is no picture or sound just backlights staying on" So the backlights are actually staying ON and will go off if you turn off the power switch but you cannot see any images on the screen?
"lg logo display for a couple of seconds" LG logo on the BEZEL or actually LG image on the LCD screen?
Are you getting 12 DCV (DCV depends on the panel design) on both ends of the SMD fuse on the T-CON board?Last edited by budm; 03-31-2016, 01:44 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 55LV5500-UA no picture or sound
LG EAY62169901 (EAX62876201/8) Power Supply 55LV5400 55LV5500 55LW5300 55LW5700
To OP, If you look at the LED connectors, you will see pin labels as 1A~C (4 STRINGS), 2A~C (4 STRINGS), 3B~C (4 STRINGS), and 4A~C (4 STRINGS) so you have total of 16 strings thus 16 Power MOSFETs for the 16 LED Cathodes return lines.Last edited by budm; 03-31-2016, 02:47 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 55LV5500-UA no picture or sound
Yes the backlights stay on when the set is powered on & turn off when turned off. The LG logo is displayed on the screen & then disappears after a few seconds. I will check the voltages of the (16) mosfets & for 12DCV SMD fuse on the T-CON board if it has one.Comment
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Re: LG 55LV5500-UA no picture or sound
Here are the voltages from the smd fuse from t-con & backlight voltages (each point being tested when powered on)
T-con smd fuse both sides 10.91 V
Starting from the lower left power ic:
1.) 12.50V at turn on then 1.6V
2.) 12.50V at turn on then 1.5V
3.) 12.50V at turn on then 1.3V
4.) 12.7V at turn on then 1.3V
5.) 12.8V at turn on then 1.3V
6.) 12.7V at turn on then 1.3V
7.) 12.3V at turn on then 1.3V
8.) 12.5V at turn on then 1.3V
9.) 12.1V at turn on then 1.1V
10.) 13V at turn on then 1.3V
11.) 12.7V at turn on then 1.1V
12.) 13V at turn on then 1.4V
13.) 12.4V at turn on then 1.2V
14.) 12.5V at turn on then 1.2V
15.) 12.4V at turn on then 1.3V
16.) 12.6V at turn on then 1.5VComment
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Re: LG 55LV5500-UA no picture or sound
"Starting from the lower left power ic:" Which IC is that? Do you mean the 16 Power MOSFETs? If those are what you are seeing, they are OK, as you indicated, the backlights STAY ON, if there was an error the backlights will be commanded to turn OFF ALL the LEDs.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 55LV5500-UA no picture or sound
So you do have Voltage to the T-CON that means the main board did not go into standby mode otherwise the DCV for the T-CON will not be there and the backlights also stay on, but you have no image on the screen so either the main board stops sending the signals to T-CON or something is going on with T-CON.
Try having one ribbon cables between the T-CON and the LCD panel connected one at time to see what you get.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 55LV5500-UA no picture or sound
Make sure the ribbon cables are properly seated back in place.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 55LV5500-UA no picture or sound
regarding to the age of the TV and environment, the Gold print on ribbon cables became very sensitive at take out and reset, check them with magnifier after you had back LG Logo take it in parts and follow post no 2.Comment
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Re: LG 55LV5500-UA no picture or sound
I will check the ribbon cable pins under magnification & will report back. The menu doesn't show either. I did find one possible cause though when I was searching the back of the main input board. I found a burned 3-pin chip with the markings (X75A) with (16) written under it. I will upload a picture of it tomorrow.Comment
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Re: LG 55LV5500-UA no picture or sound
I found out the part is a "P-Channel Enhancement Mode Field Effect Transistor" & is located in the "panel power" section on the main board. I do not have one of these on hand to replace to see what will happen.Comment
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When I plug in the power cord, Backlight LED turns on for a half second and then turns off. The red LED next to the power button located center bottom flashes 2 or 3 times. When the power button is pressed after, it does the same thing.
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