it's the power board, i know that, but i'd rather not replace it. no backlight, no standby. none of the capacitors look bulgy, fuse is good i think. can yall help me figure out what's wrong? i barely know how to use a multimeter or how to troubleshoot a circuit board but i measured ac voltage and it's like 120-140 volts up until the bridge rectifier and it turns to about 340. voltage remains that up until the legs of the transformer that meets the hot and cold side where it goes to 0 on the output of the transformer. is that normal? sometimes if i plug it in with just CNL802 (backlight) and not CNM803 (main board) the backlight flickers on but then goes off and stays off and won't do it again. it was making a baby lightning bolt when i measured DC voltage on some of the components by CNL802 but now it doesn't do it anymore. pictures are from shopjimmy, board is BN44-00666A
Samsung UN40EH5300F No Power
Collapse
X
-
Tags: None
-
Re: Samsung UN40EH5300F No Power
check the connector that goes to the PSU for burnt contacts.
With the PSU turned off, there should be 170V DC on the main filter cap. You can unplug the main board from the PSU, plug the back lights in, then plug the PSU into mains circuit. The PSU should come on and the back lights should be on and stay on. The flickering could have been an back light led going bad. Pin 12 is A5V, so this pin should have 5V STBY all the time.Last edited by CapLeaker; 06-05-2018, 07:05 PM. -
Re: Samsung UN40EH5300F No Power
check the connector that goes to the PSU for burnt contacts.
With the PSU turned off, there should be 170V DC on the main filter cap. You can unplug the main board from the PSU, plug the back lights in, then plug the PSU into mains circuit. The PSU should come on and the back lights should be on and stay on. The flickering could have been an back light led going bad. Pin 12 is A5V, so this pin should have 5V STBY all the time.
so while the board is plugged in, disconnect the main board with the backlight not plugged in, then plug in the backlight and then the main board? this did nothing.
measured DC voltage of CNL802 and CNM803 using the method in 1st pg. i have a cheap multimeter so this might be why the readings fluctuate? can't afford a nice one, that's why i'm avoiding replacing the whole board.- CNM803 is dead on all pins, 0 volts.
- on CNL802, pins 1-2 make a blue spark, jump to ~375 and slowly fall to ~295, repeating the cycle every 2-4 seconds.
- pins 3-4 do the same but jump to ~340 falling to ~260 with spark.
- pin 5 is dead.
- pins 6-7 jump to ~310 falling to ~240, no spark.
- pins 8-9 jump to ~280 and fall to ~220, no spark.
hope this helpsComment
-
Re: Samsung UN40EH5300F No Power
Put the DC Volt two meter's probes at each leg of the main filter cap CM804S, report then reading.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
-
Comment
-
Re: Samsung UN40EH5300F No Power
There's 2 parts to this test, the 170 seems about right, now hit the power button see if it goes up to about 380 or so, if so that part is ok, BE CAREFUL, this is the HOT/DEADLY side of the powersupply.Last edited by nomoresonys; 06-06-2018, 07:12 AM.Comment
-
Re: Samsung UN40EH5300F No Power
There is NO PFC Voltage booster so the Voltage on the cap will remain around 160V or so, the power supply is an always on power supply since it is the only power supply on that board, some of the outputs are switched (the one with 'B' marking).
I would like to see the pictures of YOUR board since there may be something that you did not see on your board.
DM851C is the rectifier diode for the A5V.
I would check all 7 diodes on the cold side.Last edited by budm; 06-06-2018, 10:14 AM.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: Samsung UN40EH5300F No Power
Can you provide the number on the ic on the HOT side (ic???1S) Is it a (SSC2S110) by chance? I suspect it should be operating in standby mode, which would produce the needed 5 volt standby, when the power on signal comes, opto (pc???1s) puts the ic into full on operation. and you should get the other voltagesLast edited by R_J; 06-06-2018, 11:51 AM.Comment
-
Re: Samsung UN40EH5300F No Power
There is NO PFC Voltage booster so the Voltage on the cap will remain around 160V or so, the power supply is an always on power supply since it is the only power supply on that board, some of the outputs are switched (the one with 'B' marking).
I would like to see the pictures of YOUR board since there may be something that you did not see on your board.
DM851C is the rectifier diode for the A5V.
I would check all 7 diodes on the cold side.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: Samsung UN40EH5300F No Power
There is NO PFC Voltage booster so the Voltage on the cap will remain around 160V or so, the power supply is an always on power supply since it is the only power supply on that board, some of the outputs are switched (the one with 'B' marking).
I would like to see the pictures of YOUR board since there may be something that you did not see on your board.
DM851C is the rectifier diode for the A5V.
I would check all 7 diodes on the cold side.
Can you provide the number on the ic on the HOT side (ic???1S) Is it a (SSC2S110) by chance? I suspect it should be operating in standby mode, which would produce the needed 5 volt standby, when the power on signal comes, opto (pc???1s) puts the ic into full on operation. and you should get the other voltagesComment
-
Re: Samsung UN40EH5300F No Power
OK the Diodes are not shorted.
Check DM851C in diode mode to see what you get.
The SMPS IC in question is ICM801S, it is the SMD 7-PIN IC.
BTW, when you tested the DC V on the cold side connector, is the board connected to the main board? If it is then try running the power supply board by itself to see what dc V you will get on the cold side connector.Last edited by budm; 06-06-2018, 01:59 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
-
Re: Samsung UN40EH5300F No Power
OK the Diodes are not shorted.
Check DM851C in diode mode to see what you get.
The SMPS IC in question is ICM801S, it is the SMD 7-PIN IC.
BTW, when you tested the DC V on the cold side connector, is the board connected to the main board? If it is then try running the power supply board by itself to see what dc V you will get on the cold side connector.
for the IC, i assume you mean the number printed on it and not the voltage or anything? it's 3S111, SK391, 267(and maybe a 1 or I or L)Comment
-
Re: Samsung UN40EH5300F No Power
Hmm, I would remove DM851C and re-test again in Diode mode.
I found the picture of the IC but not the spec. sheet.
https://www.aliexpress.com/item/LCD-...469463424.htmlLast edited by budm; 06-06-2018, 03:55 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
-
Re: Samsung UN40EH5300F No Power
Hmm, I would remove DM851C and re-test again in Diode mode.
I found the picture of the IC but not the spec. sheet.
https://www.aliexpress.com/item/LCD-...469463424.htmlComment
-
Re: Samsung UN40EH5300F No Power
The ic is similar to this SSC1S311, pin 1 is controlled by the opto to switch the ic out of standby condition. Check the voltage on pin 4 using the main cap's negative for meter ground
Sometimes one of those series resistors coming from the main cap's (+) goes open.Attached FilesComment
-
-
Re: Samsung UN40EH5300F No Power
seems wasteful to meComment
-
-
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
Related Topics
Collapse
-
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?by Tynan DillI 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.
Assuming...7 Photos -
by m1ch43lzmHi, 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... -
by ohrenI hope this is the right forum to post in despite not technically being a repair, but still a question of swapping boards.
I thought I'd explore the possibility to upgrade an existing working Samsung ue55nu7096u with the logic board (and power board if needed) of a newer model (ue55ru7105k) of the same size and appearance (and resolution). The reason being I'd like the extra inputs of that board including component in, an extra HDMI port and bluetooth. Its panel is broken so I have no use for the board otherwise.
The models launched in 2018 and 2019 respectively.... -
by C152HeavySamsung LN46C630K1F – Intermittent Backlight, BN44-00341B Power Board
Summary for TL-DR readers:
• Backlight is intermittent, may come on with TV boot or not. No flickering, never fails during TV on.
• Have obtained Samsung schematic & service documents - Can upload if helpful.
• Have read ALL applicable threads
• C1818 and CP820 replaced as low hanging fruit
• CN802 data taken for normal and failed BL operation. SUMMARY: Pin 2 - 5vDet = 3.52 @normal, 0.0 @BL fail. Pin 6 - EPWM = 1.631 @normal, 1.058 @BL fail.
• VCC pin (18) of PFC... -
This specification for the Samsung Galaxy Book 2 Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Galaxy Book 2 boardview and Galaxy Book 2 schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download...09-07-2024, 05:50 AM
- Loading...
- No more items.
Comment