LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

[mohsinrizwan]

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

[dskall]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Need good pictures.

[mohsinrizwan]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Front and back side pics attached

[mohsinrizwan]

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.

[dskall]

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.

[R_J]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Check if F501 is ok or open.

[mohsinrizwan]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Check if F501 is ok or open.

F501 is OK

[mohsinrizwan]

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.

Main 3 Caps has no voltage, IC501 not seeing any VCC voltage.
but 2 Caps near IC501 has 280V

[dskall]

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.

[mohsinrizwan]

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.

IC501 data sheet

https://www.alldatasheet.com/datashe...EN/A6059H.html

[mohsinrizwan]

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

[lotas]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Power Supply LG LGP4247-11SLPB
EAX62865401/8 EAY62169801

[dskall]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

So thanks to LOTAS, vcc should be 16v.

[mohsinrizwan]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

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

[lotas]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

Check these diodes for a short circuit.

[mohsinrizwan]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

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

[lotas]

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).

[R_J]

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

[mohsinrizwan]

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

Replaced both caps but no luck still 9V on VCC

[mohsinrizwan]

Re: LG TV 49LW5700 does not power no Standby Voltage(PSU EAX62865401)

any possibility I bypass standby and give 3.5V externally?