Voltage level on LCD power supply board.
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Re: Voltage level on LCD power supply board.
Hello,
I've been reading this thread to repair a Dynex DX-L40-10A tv. Had the same power supply problems described, ordered new caps from Mouser and replaced all the electrolytic caps and the film cap on the board. Put it back together and it powered right up. Unplugged it to move it to a cable outlet and back to the red LED and no picture. After opening up and testing the voltages on the main board I'm getting the following:
Main - DC Volts
+5V - 5.27
+5V - 5.27
GND - 0
GND - 0
BL ON/OFF - 0.05
DIMM - 4.06
GND - 0
+12V - 11.81
+12V - 11.81
+5VSB - 4.96
+5VSB - 4.96
ON/OFF - 2.87
GND - 0
GND - 0
I'm guessing its the main board not sending the signal to turn on the backlight. Anyone have any luck with repairing the main board?
Thanks,
mkComment
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Re: Voltage level on LCD power supply board.
You are correct, I myself never have any luck fixing the Dynex/insignia main board. Typical part to check will be the voltage regulators, check the the caps, look for burnt or damaged parts.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: Voltage level on LCD power supply board.
Budm - Is this a totally daft idea? - perhaps for a set for own use only.
What if you cut the connection to the blon pin and connect permanently to either the
dim or the 5v (with or without a resistor.) Might it then work.Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: Voltage level on LCD power supply board.
Measured the voltages on the regulators.
N1
pin 1 - 2.09
pin 2 - 3.33
pin 3 - 5.26
N7
pin 1 - 1.37
pin 2 - 2.63 - stub
pin 3 - 5.25
N10
pin 1 - 9.38
pin 2 - 0 - stub
pin 3 - 5.03
N5
pin 1 - 2.09
pin 2 - 3.34
pin 3 - 4.96
N3
pin 1 - 2.11
pin 2 - 3.37
pin 3 - 5.25
N6
pin 1 - 0.71
pin 2 - 1.42 - should be 2.6
pin 3 - 5.25
N8
pin 1 - 0
pin 2 - 0.42 - should be 1.25
pin 3 - 1.42
I don't see N9 on the board, it must be under the metal cage.
Looks like N6 and N8 are not reading the correct output voltage. Any suggestions on repairing? Should I try replacing the capacitors associated with these regulators as well as the regulators? Some I can replace, others are so small I don't think I would be successful.
I'be been looking for a main board on eBay but not much luck. There's a repair service but they don't guarantee that they can fix it.
Thanks in advance,
mkComment
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Re: Voltage level on LCD power supply board.
I would replace the N6. N8 gets it input voltage from N6 output which is too low for the N8 to work, so you need to replace N6 first. I would order 5~6 of these regulators since one is already bad, other may fail sooner or later.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: Voltage level on LCD power supply board.
Thanks for the repair feedback.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: Voltage level on LCD power supply board.
Thanks to previous posters, this thread is a great help. Question, does 22 nJ mean 22 Nanofarads? (the "J" is confusing me)
My Dynex TV with the same symptoms, (Red Light On but TV won't power up).
Just want to make sure I am ordering the correct value capacitor.
Mine says: (this is cap # c842)
CBB81
2000v
22nJComment
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Re: Voltage level on LCD power supply board.
This thread is getting long, so what the exact problem do you have? Post the pictures of YOUR board will help, you also need to get at least a meter to make some measurement.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: Voltage level on LCD power supply board.
Hi there. I finally got the power supply installed, the TV turns on and all inputs work well except for the TV tuner. There were no issues with the tuner before the new power supply.
I noticed that the jumpers in this pic were set differently than the new one. Is there any chance that this could be the issue with the tuner?
http://i741.photobucket.com/albums/x...ps7a1d0ffe.jpgComment
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Re: Voltage level on LCD power supply board.
http://www.eserviceinfo.com/download....820.1673.htmlComment
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Re: Voltage level on LCD power supply board.
Hi a good day to you al. I am having some issues with a power supply and would surely appreciate some help. This is a DPS-286AP IT HAS NO 5 volts standby. R7914 was replaced. D7908 was replaced. I have 175volts across The diode. Can anyone assist me with The troubleshooting.??Comment
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