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Old 05-28-2022, 10:35 AM   #1
mohsinrizwan
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Default LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Hello,

I have LG 49LW5700 which is not turning on, when I checked there was no standby (3.5V) can anyone guide how I can trace which component is faulty.

Thanks
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Old 05-28-2022, 10:44 AM   #2
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Need good pictures.
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Old 05-28-2022, 10:54 AM   #3
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Front and back side pics attached
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File Type: jpg 20220528_214652.jpg (1.14 MB, 7 views)
File Type: jpg 20220528_214729.jpg (1.66 MB, 5 views)
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Old 05-28-2022, 10:56 AM   #4
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

FYI, I only need this PSU to turn on Backlights, I am using third party main board as original LG mainboard always go bad after 4-5 months. I only need this PSU to turn on backlights and supply 12V to third part main board.
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Old 05-28-2022, 12:31 PM   #5
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

If you have no voltage, check for voltage at one of the 3 main caps. If voltage then check ic501 for vcc voltage, datasheet.
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Old 05-28-2022, 12:50 PM   #6
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Check if F501 is ok or open.
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Old 05-28-2022, 01:12 PM   #7
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by R_J View Post
Check if F501 is ok or open.
F501 is OK
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Old 05-28-2022, 01:13 PM   #8
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by dskall View Post
If you have no voltage, check for voltage at one of the 3 main caps. If voltage then check ic501 for vcc voltage, datasheet.
Main 3 Caps has no voltage, IC501 not seeing any VCC voltage.
but 2 Caps near IC501 has 280V

Last edited by mohsinrizwan; 05-28-2022 at 01:23 PM..
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Old 05-28-2022, 01:30 PM   #9
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Not sure. Ic501 may be driver for backlights. I'm no expert. I would need to see datasheets for driver IC's.
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Old 05-28-2022, 01:36 PM   #10
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by dskall View Post
Not sure. Ic501 may be driver for backlights. I'm no expert. I would need to see datasheets for driver IC's.
IC501 data sheet

https://www.alldatasheet.com/datashe...EN/A6059H.html
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Old 05-28-2022, 01:45 PM   #11
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

my bad, VCC on IC501 is 9V which should not exceed 3-5V
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Old 05-28-2022, 01:49 PM   #12
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Power Supply LG LGP4247-11SLPB
EAX62865401/8 EAY62169801
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Old 05-28-2022, 02:05 PM   #13
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

So thanks to LOTAS, vcc should be 16v.
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Old 05-28-2022, 02:07 PM   #14
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by lotas View Post
Power Supply LG LGP4247-11SLPB
EAX62865401/8 EAY62169801
I am not pro but know basic things, I can give supply to local tech but in my City we don't have nay good tech who understand things
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Old 05-28-2022, 02:33 PM   #15
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Check these diodes for a short circuit.
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Old 05-28-2022, 02:47 PM   #16
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by lotas View Post
Check these diodes for a short circuit.
both are good, not short.

Also I am not getting 220V and on stand by bridge should generate 66V which its isn't
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Old 05-28-2022, 03:11 PM   #17
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

You will not have power on the diode bridge until the relay turns on (transition to operating mode), now power is supplied through these diodes D501-D504 (standby mode).
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Old 05-28-2022, 05:16 PM   #18
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

With ic501 vcc at 9v, this suggests the startup cell internally is working. I suspect C508 and C507 could be bad, I would first replace C508 and see if the vcc comes up.
I would also check the voltage on pin4 FB/OLP

Last edited by R_J; 05-28-2022 at 05:21 PM..
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Old 05-29-2022, 04:04 AM   #19
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Quote:
Originally Posted by R_J View Post
With ic501 vcc at 9v, this suggests the startup cell internally is working. I suspect C508 and C507 could be bad, I would first replace C508 and see if the vcc comes up.
I would also check the voltage on pin4 FB/OLP
Replaced both caps but no luck still 9V on VCC
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Old 05-29-2022, 04:05 AM   #20
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Default Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

any possibility I bypass standby and give 3.5V externally?
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