so I received this tv with no main in it, so I purchased a new main which they only have 1 for this model which I was lucky. and the backlights are not turning on. and it has a ribbon going from the power supply to the main so I don't know how to check the voltages but I checked it at the inverter and it is getting the 24 volts, so I thought maybe it was inverter. so I swapped it with another one I already had and it still didn't work, so is it possible the mains bad? I thought that as long as the 24 volts is going to the inverter that the backlights would be on?
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Re: hitachi L40A105E no backlights
here is the set up and I even disconnected the cable that goes from top panel from the main and still nothingAttached Files -
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Re: hitachi L40A105E no backlights
Check for fuses on the inverter(s). When you find them, check to see if they are good. If they aren't, replace them.Comment
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Re: hitachi L40A105E no backlights
You have 24VDC for power but do you BL-ON & Dimm control signals from the main board to turn on the inverter circuit?
Is this your inverter board?
http://www.shopjimmy.com/samsung-lj9...-inverter.htm#Last edited by budm; 07-16-2015, 12:27 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: hitachi L40A105E no backlights
yes bud m it is, and I have 2 inverters both with good fuses. im alittle confused I thought that if there was 24 volts to inverter that it automatically would turn on? so you saying that even if there is 24 volts going to inverter that the main could still be bad? if you look at the set up its a ribbon cable so I don't know how to check for bl on and dimComment
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Re: hitachi L40A105E no backlights
"I thought that if there was 24 volts to inverter that it automatically would turn on? so you saying that even if there is 24 volts going to inverter that the main could still be bad?" The inverter has to be able to go off when the TV is in standby mode (not powered off mode) when no Video signal is detected.
If you look at the big white connector, you will see the pinout chart of the connector, you need to check the DCV of the ENA pin, DIM pin, Ex_dim pin with ref to the chassis GND.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: hitachi L40A105E no backlights
bud there is no labels on the power supply or mainComment
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Re: hitachi L40A105E no backlights
The large connector (the one that goes to the power supply baord) on the inverter board is the one I am talking about, sorry for not being clear.Attached FilesLast edited by budm; 07-16-2015, 03:58 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: hitachi L40A105E no backlights
ex dim 3.25
dim 2.75
ena 0
so does that mean bad main since ena is 0? and what is ena? and could I repair something on the main to fix this?Comment
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Re: hitachi L40A105E no backlights
ENA = Backlights Enable = BL-ON, <1V = OFF, >2.5V = ON. so your main board is not sending out or may be the new main board pinout is not the same as the old board.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: hitachi L40A105E no backlights
Is there anyway to fix this on the main boardComment
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Re: hitachi L40A105E no backlights
Do you have service manual that shows all the details schematic of the main board and can you read the schematic in details?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: hitachi L40A105E no backlights
You need to trace that BL-ON pin on the main board to see where it goes to, probably a switched transistors that get the command signal from the processor, to test the IC or transistor you will need to know what they are by looking at the spec sheet.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: hitachi L40A105E no backlights
Bud thanks alot I will try to figure it out I'm new to stuff like this but I like learning how this works. I can easily diagnose a tv and swap a board but I wanna learn how to get down to component level and suchComment
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Re: hitachi L40A105E no backlights
Right now what you can do is to disconnect the ENA pin from the connector, then a 500~1K between the ENA pin on the inverter board and the 5VSTBY pin to force on the backlights so you can see if you do get the pictures on the screen, if not then you have more than one problems on that main board.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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I just got this tv today and it appeared to have no backlight on. After taking off the rear cover and checking again in the dark I can see that MAYBE one quadrant is lit.. But still it's quite dim. I was going to check the LEDs with my tester, and I found LED 1 and LED 2 + pins on the wire from the inverter, but I couldn't identify a ground. Nonetheless I tried using a mounting screw on the inverter board and also the chassis as ground but regardless my tester reads 300 which is what it reads when there is no voltage draw.
I don't know how exactly to test the inverter itself. Is it... -
Hello, I came here after finding some similar questions asked on other monitors and hope someone here can help me get an ancient Viewsonic VP230mp (23" 4:3 LCD) back to working condition.
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Hi everyone,
Iām looking for help with a persistent issue on an LG TV model 55NANO77SRA, which uses the main board EBU66792103 (also used in LG UQ80 and NANO75/NANO80 series).
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- I removed the physical button board (the entire panel with power and volume buttons) and also disconnected the flat cable (CN202) from the main board.
- The remote control is not in use (batteries removed), and the TV still shows the same behavior.
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Hoping someone here could possibly help. I have a few questions in regards to compatibility with main boards. But I'll give a quick short run down on what's going on first;
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