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Old 01-18-2018, 11:38 AM   #21
budm
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Default Re: LG 60LB5200 will not turn on

BTW, did you look into as to how much the replacement board is and the replacement IC is?
You also need to read the spec sheet of that IC and the explanation about how IC function, look at the schematic on page 5 and trace out your board to see how close it is to your board, you need to do some works and study and do the research instead of keep typing "Have I stumped the experts?"
We are not stumped, we have no schematic of the board, we do not have the board in front of us, we have to do the reverse engineering without having the board in front of us so expert or not it is not easy task and it does not help when we get the wrong data.
If you want faster service I would suggest you to buy replacement board, you are not the only one asking for free help.
Do you know how much time I spent to trace out the circuit to find out why you are not getting the VCC but to find out later that DATA was wrong?
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Basic LCD TV and Monitor troubleshooting guides.
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Voltage Regulator (LDO) testing:
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Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

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Last edited by budm; 01-18-2018 at 11:52 AM..
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Old 01-18-2018, 12:55 PM   #22
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Default Re: LG 60LB5200 will not turn on

My apologies. I have a lot of respect for your knowledge and time.

I originally was just wanting to confirm that it was the power supply that was at fault. Then you and maxvalutech started offering troubleshooting tips. So, I figured I would just go the route of trying to fix it with your guidance.

I have looked for a replacement board with no luck. Every website that I have found shows out of stock and no expected replacement stock.

Last edited by WTRWLKR; 01-18-2018 at 01:06 PM..
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Old 01-18-2018, 01:22 PM   #23
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Default Re: LG 60LB5200 will not turn on

Not knowing enough about how this works, is the power supply in an always on state or does it wait for a signal on EN, to activate the power supply?
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Old 04-10-2018, 04:04 PM   #24
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Default Re: LG 60LB5200 will not turn on

having similar issue. plugged in the tv constantly has the green LED on but it is slightly flickering(no Pic on TV). tv will not turn off(red LED). when I took off the back panel all components look fine (nothing burnt/swollen that I can see). when I remove the connector from the pwr supply and apply pwr I'm getting all the 24v and 12v but cant get the 5v standby. once I plug all the cards back into the pwr supply the main board starts making a slight clicking noise and the pwr supplys 24v and 12v drop to 12v and 6v (half voltage)
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Old 04-10-2018, 04:43 PM   #25
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Default Re: LG 60LB5200 will not turn on

Quote:
Originally Posted by kyle37095 View Post
having similar issue. plugged in the tv constantly has the green LED on but it is slightly flickering(no Pic on TV). tv will not turn off(red LED). when I took off the back panel all components look fine (nothing burnt/swollen that I can see). when I remove the connector from the pwr supply and apply pwr I'm getting all the 24v and 12v but cant get the 5v standby. once I plug all the cards back into the pwr supply the main board starts making a slight clicking noise and the pwr supplys 24v and 12v drop to 12v and 6v (half voltage)
Are you sure you do not have 5V standby? The 24V and 12V power supply will not work without the standby power supply running because the standby power supply provides the VCC to run the SMPS IC for the 12V/24V power supply.
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Old 04-10-2018, 09:10 PM   #26
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Default Re: LG 60LB5200 will not turn on

I measured from connector point en to case gnd and didn't get anything.
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Old 04-11-2018, 09:30 AM   #27
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Default Re: LG 60LB5200 will not turn on

Please upload good clear pictures of YOUR board, I need to see that pin.
https://www.badcaps.net/forum/attach...0&d=1513110658
The board of OP in POST one does not have STANDBY pin, it is an always on power supply with only one transformer without standby power supply transformer.

Last edited by budm; 04-11-2018 at 09:34 AM..
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Old 04-11-2018, 10:21 AM   #28
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Default Re: LG 60LB5200 will not turn on

Mine is exactly the same tv and pwr supply
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Old 04-11-2018, 10:28 AM   #29
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Default Re: LG 60LB5200 will not turn on

"but cant get the 5v standby"
If it is the same board then I do not see 5V STANDBY pin, where is it?
The connector has 12V, 24V, EN, and GND.
EN = PS-ON which is the command signal from main board, it should change state when power switch is toggled on and off.

" once I plug all the cards back into the pwr supply the main board starts making a slight clicking noise and the pwr supplys 24v and 12v drop to 12v and 6v (half voltage)"
That means the power supply is weak due to problem or the main board is drawing too much current which causes the power supply to go into shutdown/startup cycle.

Last edited by budm; 04-11-2018 at 10:38 AM..
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Old 04-11-2018, 01:01 PM   #30
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Default Re: LG 60LB5200 will not turn on

ok then this one does not have a standby then.. good to know!. how can I troubleshoot to see what board is the issue? I would rather spend 100$ on 1 board than 200$ on 2 separate boards.
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Old 04-11-2018, 01:28 PM   #31
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Default Re: LG 60LB5200 will not turn on

The key point is when all the boards are connected together do you see the DC Voltage ON the EN pin change state when power switch is toggled.
The power supply does have standby Voltage, 12V (isntead of typical 3.3V or 5V), when PS-ON is present then the 24V power supply is turned on.
As I indicated in post 39:

" once I plug all the cards back into the pwr supply the main board starts making a slight clicking noise and the pwr supplys 24v and 12v drop to 12v and 6v (half voltage)"
That means the power supply is weak due to problem or the main board is drawing too much current which causes the power supply to go into shutdown/startup cycle.
You can test the power supply board by forcing it on and use dummy load on the 12V and the 24V to pull the rated current of the power supply to see if it can handle the load or not.

Last edited by budm; 04-11-2018 at 01:30 PM..
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Old 04-11-2018, 02:02 PM   #32
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Default Re: LG 60LB5200 will not turn on

budm just a general question can car 12v bulbs be used to load test a psu as most people have these handy will they draw enough current?
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Old 04-11-2018, 05:23 PM   #33
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Default Re: LG 60LB5200 will not turn on

En vdc is 2.5v no matter what. 24v pwr supply output is 15v constant and 12output is at 6v constant. Main board is still making a very quiet pew pew sound. Green led light on the bottom of the tv is still constantly lightly flickering
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Old 04-11-2018, 09:35 PM   #34
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Default Re: LG 60LB5200 will not turn on

OK, let me get this straight, if you run the power supply board by itself without having the main board connected, the 24V and the 12V power supply is steady, if it is then you need to check the DC Voltage between the two legs of the main filter cap to see if you have about 380 ~ 400VDC or not, the OP's board has problem with PFC Voltage booster section.
Be real careful because you are making the measurement in the HOT DEADLY side of the circuit.
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Old 04-11-2018, 09:44 PM   #35
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Default Re: LG 60LB5200 will not turn on

Quote:
Originally Posted by vinceroger69 View Post
budm just a general question can car 12v bulbs be used to load test a psu as most people have these handy will they draw enough current?
It depends on how sensitive the over current shutdown circuit is because the Cold resistance of incandescent lamp is very low so the power supply will see very high surge current.
The cold resistance of the incandescent lamp is about 15 times lower than the hot resistance. I.E. 12V 12Watts lamp has hot resistance of 12 Ohms (1A of current) that means the cold resistance will be <1 Ohm so the current will be very high (>12A) for short period of time when 12V is first applied.
You can easily check the cold resistance of the lamp with Ohm meter.
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Old 04-14-2018, 07:36 PM   #36
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Default Re: LG 60LB5200 will not turn on

450vdc caps are reading 167vdc. I unplugged all the cards north of the pwr supply. Still out putting 16v for 24 v pins. That is new it was outputting 24v on 24v pin?
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Old 04-14-2018, 07:44 PM   #37
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Default Re: LG 60LB5200 will not turn on

Quote:
Originally Posted by kyle37095 View Post
450vdc caps are reading 167vdc. I unplugged all the cards north of the pwr supply. Still out putting 16v for 24 v pins. That is new it was outputting 24v on 24v pin?
Is this reading of 167V with the EN pin at >2V DC? If EN signal is not present then the PFC will not work same for the rest of the switched power supply section.
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Old 04-14-2018, 07:46 PM   #38
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Default Re: LG 60LB5200 will not turn on

Took the card off the tv and something sounds like it has sand in it but I can't tell what component it is
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Old 04-14-2018, 07:47 PM   #39
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Default Re: LG 60LB5200 will not turn on

Even with everything plugged it it's still at 167vdc
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Old 04-27-2018, 05:31 AM   #40
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Default Re: LG 60LB5200 will not turn on

Did you ever resolve this? I have the same model and get the same readings. I swapped out the main board with no luck. No one has a power supply board in stock, so I canít try that.
I know how to use a multimeter and solder electronics but no diagnostic ability. The tv is only a few years old and I donít want to have to buy another.
This was our everyday tv that sat in our dining room for a month while we remodeled. Plugged it in and all I get is the flickering green light.
I appreciate any and all help.
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