Hello everyone. The tv wont turn on. It got a red standby light that blinks as when pushing power on button. The tv has been laying for about 1 year now but what happened was that i was plugging i an antennea cable or maybe vga(cant remember which one it was ) and it just died instantly. Attaching pictures of the tv and the boards. I alson took some voltage readings as in one of the attached images. Someone who can point me in the right direction on repairing it? And btw, the readings i got was when plugging the powercord in and measured it in standby mode.
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LG 55LM620T-ZE Not turning on
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Re: LG 55LM620T-ZE Not turning on
do you have a couple of 1k resistors to jump the ps on?Last edited by attainteddragon; 06-30-2018, 07:24 AM.WHY CAN'T PHILIPS USE PHILLIPS HEAD SCREWS?
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Re: LG 55LM620T-ZE Not turning on
All the secondary voltages appear to be up and running but you don't give the voltages for DRV_ON or ERROR.Last edited by dick_barton; 06-30-2018, 08:56 AM.Willing to help but I'm no expert.
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Re: LG 55LM620T-ZE Not turning on
I saw now in my first that i wrote what could be misunderstood. To clarify, when I plug the cord in the red light goes on and stays like that until i press the power button, then it starts blinking and keeps doing that for a while before it goeas back to a static light. Some additional info is that i have a green led on the powerboard that after the tvhave been connected for about 30 secs start to blink. Blinks 5 times pauses and then 5 times again and keeps going like that.
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Re: LG 55LM620T-ZE Not turning on
DRV_ON is missing and should be around 3V to activate the backlight led circuitry. It's a signal from the mainboard so you may have a led fault giving an Error response turning off the DRV_ON signal.
Can you check what voltage is at PWR_ON when in standby and when you switch it out of standby. Some PWR_ON need to the voltage on the pin to go low to come out of standby and some need to go high to come out of standby.Last edited by dick_barton; 06-30-2018, 09:31 AM.Willing to help but I'm no expert.
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Re: LG 55LM620T-ZE Not turning on
Originally posted by Andrew F. Ali View PostI noticed that on the pin labelled N.C (Not Connected) you have 12V. That is not right. I think there is an error in your readings Perhaps you could label the pins as pin1 ERR 12 V, pin 2 PS-ON 3.5V just as an example.
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Re: LG 55LM620T-ZE Not turning on
Originally posted by dick_barton View PostDRV_ON is missing and should be around 3V to activate the backlight led circuitry. It's a signal from the mainboard so you may have a led fault giving an Error response turning off the DRV_ON signal.
Can you check what voltage is at PWR_ON when in standby and when you switch it out of standby. Some PWR_ON need to the voltage on the pin to go low to come out of standby and some need to go high to come out of standby.
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Re: LG 55LM620T-ZE Not turning on
can you disconnect the loom that goes from the p/s to the main and measure what the ps/on pin reads. this will let us know if it requires a high or low voltage control to turn on.
your current measurement is what i would call neither, so need to confirm this.WHY CAN'T PHILIPS USE PHILLIPS HEAD SCREWS?
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Re: LG 55LM620T-ZE Not turning on
https://www.badcaps.net/forum/attach...9&d=1530363633
Based on what you show, the PWR_ON is fine otherwise not ALL the switched power supplies will be putting out. You can easily verify if the PWR_ON is OK or not by checking the DCV right between the two legs of the main filter cap, if you have close to 400VDC then the PWR_ON signal is OK otherwise you will not have PFC Boosted Voltage on the main filter cap. The PWR_ON may be stuck ON at this point if it does not toggle to 0V (= off). Some power supply boards do use <1V = ON, 0V = OFF instead of typical 2 ~5 V = ON, <1V = OFF.
You do not have Dimming control on one of the pin but not at the other P-DIM pin? Backlights ON signal is not present.Last edited by budm; 06-30-2018, 08:23 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=24809
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Re: LG 55LM620T-ZE Not turning on
Originally posted by attainteddragon View Postcan you disconnect the loom that goes from the p/s to the main and measure what the ps/on pin reads. this will let us know if it requires a high or low voltage control to turn on.
your current measurement is what i would call neither, so need to confirm this.
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Re: LG 55LM620T-ZE Not turning on
Originally posted by budm View Posthttps://www.badcaps.net/forum/attach...9&d=1530363633
Based on what you show, the PWR_ON is fine otherwise not ALL the switched power supplies will be putting out. You can easily verify if the PWR_ON is OK or not by checking the DCV right between the two legs of the main filter cap, if you have close to 400VDC then the PWR_ON signal is OK otherwise you will not have PFC Boosted Voltage on the main filter cap. The PWR_ON may be stuck ON at this point if it does not toggle to 0V (= off). Some power supply boards do use <1V = ON, 0V = OFF instead of typical 2 ~5 V = ON, <1V = OFF.
You do not have Dimming control on one of the pin but not at the other P-DIM pin? Backlights ON signal is not present.
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Re: LG 55LM620T-ZE Not turning on
Originally posted by attainteddragon View Postok, so your main is stuck on. i'm not sure if you can get an eeprom for this board, or you would be looking at a replacement.
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