42PFL7406 No Power
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Re: 42PFL7406 No Power
What voltage do you have across C908 and also at the FB pin 2 of IC901 and are they steadyLast edited by dick_barton; 08-12-2020, 09:38 AM.Willing to help but I'm no expert.Comment
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Re: 42PFL7406 No Power
It looks like your pfc circuit is switching on when the voltage across C908 reaches 18V and then stopping when the voltage falls which would be the reason your secondary voltages are oscillating.
It does look like a short but is it the zener or R902 since that is across ZD904. You could lift one end of ZD904 to test it or it could be a short on the IC pin to ground.
CS is the current source pin which would have a low value resistor (R902) attached to it and hot ground.Last edited by dick_barton; 08-12-2020, 12:35 PM.Willing to help but I'm no expert.Comment
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Re: 42PFL7406 No Power
47Y is 47 ohms according to http://kiloohm.info/eia96-resistor/47Y
Are you certain it's 47Y since that seems to be a high value resistor as a source resistor.Last edited by dick_barton; 08-12-2020, 01:01 PM.Willing to help but I'm no expert.Comment
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Re: 42PFL7406 No Power
I forgot about this thread, too busy with the 37" & 47" threads.
So at this point if you run the power supply board by itself and force it on, is the PFC boost Voltage staying on?Last edited by budm; 08-12-2020, 03:52 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: 42PFL7406 No Power
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: 42PFL7406 No Power
What are the values of R959 & R960.
For standby: - do you have a couple of resistors you could put in parallel. e.g. 2 x 1K in parallel = 500 ohmsLast edited by dick_barton; 08-13-2020, 04:45 AM.Willing to help but I'm no expert.Comment
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Re: 42PFL7406 No Power
Looking at those values I think it's safe enough to short standby to ground.Willing to help but I'm no expert.Comment
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Re: 42PFL7406 No Power
I suggest using resistor just in case OP ground the wrong pin on the connector by mistake if he jumps directly, OP can jump STANDBY pin to ground directly with no problem, I am just afraid that OP will make mistake and ground the wrong pin.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
-
Re: 42PFL7406 No Power
So is the PFC Boosted Voltage present then?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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