I have a board that measures 357v with pfc. 162v in standby. I have read that it should be >360v. I know things don't work if pfc is missing, but what problems would it cause if just low? Is pfc a monitored voltage if low would it cause shut down?
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I assume no responsibility for any stupid suggestions I might post. -
Re: PFC low?
Common problem for having low PFC is due to the resistors in the feedback string that the resistance has changed.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 -
Re: PFC low?
I don't think 357 volts is low, pfc is working. if ac line was a couple volts low that could effect the dc voltage in standby and when the pfc is workingComment
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Re: PFC low?
In most Samsung if it goes below 360, the INVERTER or LED backlights circuit will go into shutdown.
We do not know what power supply he is working on. Some other brands may not have that protection for low PFC but will have PFC Over Voltage shutdown.
There are the so call fix for the SAMSUNG that has Backlights flashing problem and the supposed fix is to cut open a jumper, that jumper is for the LOW PFC Voltage shutdown protection, so when the jumper is cut the protection is no longer in place, I found and fixed the cause of the problem correctly due to resistors have drift off in value.Last edited by budm; 02-06-2017, 06:24 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: PFC low?
o.k. I did'nt think the pfc was that tightly regulated.Comment
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Re: PFC low?
What would a proper working range be for PFC voltages?I assume no responsibility for any stupid suggestions I might post.Comment
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