hello, I picked this TV up for free and started to diagnose it. I assume either a main board issue or shorted LED's. When I power it on, my voltages come up correctly and the LED's light for a split second. Then the entire system shuts down. No voltage anywhere. I assume shorted LED's forcing the PSU into protect so I disconnected the LED connector, powered on again, and the same issue occurred. Voltages came up for a second and then everything shut down. Any ideas?
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RCA LED65G55R120Q No Backlight
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Re: RCA LED65G55R120Q No Backlight
Pictures of what we are dealing with will help.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=24809
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Re: RCA LED65G55R120Q No Backlight
"When I power it on, my voltages come up correctly and the LED's light for a split second."
So what DC Voltages do you have on the control pins of the power supply board connector CN2: ADJ, BK, and PS?
What Voltages do you have on the LED connector pins with LED connector in place? You need to leave the probe on each pin and then Turn on the TV to see how high it goes up to then wait 5 seconds to see how low it goes down to, do that on each pin of the LED connector, black probe on the chassis GND, you have two LED (+) and two LED (-) so 4 tests total.Last edited by budm; 01-23-2019, 11:34 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=24809
Comment
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Re: RCA LED65G55R120Q No Backlight
Voltage checks are a must as budm has indicated. A year ago I had set from friend of friend with similar problem except logo displayed. Power board and LEDs checked out OK by forcing them on. That left me with likely eeprom corrupted on main board. That set 65" Polaroid similar to RCA was recently given to me and I will first be trying freeze spray on the eeprom.
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Re: RCA LED65G55R120Q No Backlight
Originally posted by budm View Post"When I power it on, my voltages come up correctly and the LED's light for a split second."
So what DC Voltages do you have on the control pins of the power supply board connector CN2: ADJ, BK, and PS?
What Voltages do you have on the LED connector pins with LED connector in place? You need to leave the probe on each pin and then Turn on the TV to see how high it goes up to then wait 5 seconds to see how low it goes down to, do that on each pin of the LED connector, black probe on the chassis GND, you have two LED (+) and two LED (-) so 4 tests total.
PS-5Vs: 5.1v always
ADJ-BK: 1.6v when turned on, drops to 0
5V+5V: 4.9v once powered on, then drops to 0
LED Connector (left to right)
+: 285V drops to 0 in five seconds
-: no reading
+: 135V drops to 0 in 5 seconds
-: no readingLast edited by zacheriaj; 01-30-2019, 04:59 PM.You Can't Succeed Until You're Willing to Fail
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Re: RCA LED65G55R120Q No Backlight
Originally posted by zacheriaj View PostSorry for the delay. I'm in WI and its been a rough week! Finally got voltages for you.
PS-5Vs: 5.1v always
ADJ-BK: 1.6v when turned on, drops to 0
5V+5V: 4.9v once powered on, then drops to 0
LED Connector (left to right)
+: 285V drops to 0 in five seconds
-: no reading
+: 135V drops to 0 in 5 seconds
-: no reading
Pin name assignment for example: Pin 17 is ADJ (DIM control), Pin 18 is BK (BL-ON).
1) So to troubleshoot the problem we will need correct data first.
2) I need the pictures of the bottom side of the power supply board to see if the two LED strings are connected in series or not.
This looks to be the same as your board:
https://www.shopjimmy.com/rca-re46hq...led-board.htm#
RCA RE46HQ2120 Power Supply / LED BoardNever 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=24809
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