Re: Need help with Samsung LN40E550f7f
Wonder if there are any bad/cold solder joints, did you look them over real close?
Wonder if there are any bad/cold solder joints, did you look them over real close?
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Re: Need help with Samsung LN40E550f7f
439V is way too high, the cap is rated at 450V, so the PFC goes into shutdown and all you will get is 160V on the cap as expected when PFC is shutdown, It may have PFC Output Voltage sensing feedback issue.
Original OP PFC Voltage reading:
Last edited by budm; 07-26-2019, 12:24 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: Need help with Samsung LN40E550f7f
Found SMD DP807 on the foil side shorted, i will remove it and retest.Comment
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Re: Need help with Samsung LN40E550f7f
DP807 is connected to the CS pin4 f the PFC controller ic.
pin 4 CS
This pin is the input of the over-current protection comparator. The MOSFET current is sensed
using a sensing resistor and the resulting voltage is applied to this pin. An internal RC f ilter is
included to f ilter sw itching noiseComment
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Re: Need help with Samsung LN40E550f7f
There should be OVP sensing pin on the PFC IC.
What is the your PFC IC number?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: Need help with Samsung LN40E550f7f
Isn't it connected in parallel with the PFC MOSFET Source pin current sensing resistor which will be < 1 Ohm resistor.Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by budm; 07-26-2019, 01:07 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: Need help with Samsung LN40E550f7f
https://cdn.badcaps-static.com/pdfs/...0db2152410.pdf
See schematic on page 18.
Pin 2:OVP
There are bunch of Resistor network for the PFC Output Voltage sensing, if the resistors go up in value that will cause the output to go high than what is intended.Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by budm; 07-26-2019, 01:07 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: Need help with Samsung LN40E550f7f
Bud, you see DP807 if it's shorted you think thats the problem?Attached Filesif you find these attachements useful please consider making a small donation to the site
Comment
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Re: Need help with Samsung LN40E550f7f
DP807 is not shorted out of circuit.Comment
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Re: Need help with Samsung LN40E550f7f
If your pfc comes up for a second like you said, the circuit is likely working fine and is just not being told to turn on, check the VCC voltage for that circuit, it is usually controlled by a transistor (QM504) which could be controlled by an optocoupler (PCM802S).
Check your voltage on JP826, next to cap CM815, That voltage should be around 25 volts. If the voltage is there, check the voltage on QM504, (all three pins) and post itLast edited by R_J; 07-26-2019, 04:50 PM.Comment
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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: Need help with Samsung LN40E550f7f
BTW:
INV pin 1 is for the feedback for controlling the Boosted Output Voltage, the network resistors in this section are the one to check.
OVP pin 2 is the Over Voltage sensing that tells the circuit to go into shutdown if the Output Voltage is too high.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: Need help with Samsung LN40E550f7f
Just looking at this thread https://www.badcaps.net/forum/showth...ln46d550k1fxza and in post #8 (same fan7930) He was getting a pfc voltage pulse of 430v, Changing the ic solved his problem, so maybe thats the case here?Comment
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Re: Need help with Samsung LN40E550f7f
Jumper jp826 has 17.5DCV
QM504 has 17.0 DCV on all 3 pins..Comment
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Re: Need help with Samsung LN40E550f7f
Ok, then it should be supplying VCC to the pfc ic pin 8, which is good, but it could be the pfc ic is shutting itself down, I posted in #215 (see how long hijack threads get) that someone else had a similar issue with high pfc voltage and the same ic number and it turned out to be the ic that was bad.Comment
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Re: Need help with Samsung LN40E550f7f
Replacing the PFC IC at this point may be a good thing to try, seems to be common failure, thanks RJ for finding the thread from 2016.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: Need help with Samsung LN40E550f7f
There's the repair kit: https://www.shopjimmy.com/samsung-bn...repair-kit.htmLast edited by nomoresonys; 07-27-2019, 03:54 AM.Comment
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Re: Need help with Samsung LN40E550f7f
there it is on ebay, from shopjimmy: https://www.ebay.com/itm/Samsung-BN4...AAAOSwwq1as-DGComment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
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Hey everyone,
This power supply board is hard to find but there are repair kits available. This board had a blown fuse, FP801S, blown PFC MOSFET, QP802CS and ceramic cap, CP809. I replaced them with parts I already had and tested the rest of the parts that would've come in the repair kit and they were fine. I powered the board up on the bench expecting, in typical Samsung power supply board fashion, to see all my output voltages but, nothing. 0 volts on CNL801, CNM801 and CNT801. The only thing I have is 170vdc on the filter caps. No standby voltage either.
Anybody... -
I did not have any 27uf @ 50 volt capacitors but one nice thing is that it has enough room for two capacitors in parallel a 22uf and a 4.7uf @ 50 volts 22 plus 4.7 equals 26.7uf which so very close to 27uf I will show some pictures of it sometime tomorrow
This is one of the shit est boards I seen in a very long time and it was the daughter board the traces just lifting off the board I had to use the capacitor leads to repair the the traces and the main board is not any better because I had to repair several traces for the daughter board to the main board
After all of... -
I am attempting to test a samsung power supply board to verify the pfc ic is working. I am powering up the board with my isolation transformer. The board turns on fine but when I attempt to connect the ground for the scope probe, it trips out the isolator. I was taught not to 'float my scope' so I am wondering if I should test without connecting the ground lead or would that be asking for trouble? Not sure how else to test, I don't have a portable scope. I could plug direct to mains power but that would bypass the safety factor.
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Hi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic...
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