Hi Everyone, I am new to this forum. I have a Panasonic LED TV which doesnt turn on and is blinking 4 times repeatedly when I turn on the switch. The TV does not respond to the remote control so I had to turn on using the physical switch on the side of the TV. When I turn on the switch the 4 x blinking starts and repeat itself until I turn off the TV. There is a black screen. I turned off the light in the room to check the panel and I think there is no backlight as far as I can tell.
I have been inspecting and testing the capacitors and diodes in the power supply board to try to find the problem. But no luck so far.
Initially I had tried to use the DMM to measure the voltage of the DC output pins (called "P2" in the diagram) from the power board to the "A board" (which I understand will further regulate the DC voltage). I have attached a copy of the Panasonic troubleshooting notes that I have found on the web which outline the voltage distribution for this particular LED TV model. I believe I was not successful in testing the voltage because the pins were very narrow and the leads from my DMM could not accurately touch the specific pins of the voltage output. From the few pins that I had tried, they all turn out to be nil voltage, which is strange because I am still getting the 4 blinks which presumably means there should be some DC output coming out of the power board, is that right?
When I was doing the voltage testing, I placed the black lead (from DMM) to one of the holes in the metal plates behind the circuit boards and let it hang there. Is this the right approach? Are these holes appropriate for "ground". I have seen some youtube videos showing that the black lead should touch the "ground" pin in whatever that I was checking, and I had tried that as well but there were still no voltage in the output pins.
Also, while I was testing the voltage on the pins, there were few instances when the TV will restart itself as if I had physically turn on the switch again. Does anyone knows why this happens? How does me checking the voltage on the output pins will make the TV restart and turn on again? I am very conscious of the fact that there is high voltage involved in the power board so I had been very careful in not touching anything other than using the leads on the DMM.
Sorry for the long post, but I was hoping someone can have a look at the attached notes on voltage distribution and let me know what is the proper way to check the voltage output and whether the results can then narrow down the cause of the problem. In case it is also useful, I have found and also attached a schematic of the power board, but the schematic doesnt show details of the component, so there is no way of knowing the values of the various components, eg. resistance, capacitance etc.
Thank you for your help!
I have been inspecting and testing the capacitors and diodes in the power supply board to try to find the problem. But no luck so far.
Initially I had tried to use the DMM to measure the voltage of the DC output pins (called "P2" in the diagram) from the power board to the "A board" (which I understand will further regulate the DC voltage). I have attached a copy of the Panasonic troubleshooting notes that I have found on the web which outline the voltage distribution for this particular LED TV model. I believe I was not successful in testing the voltage because the pins were very narrow and the leads from my DMM could not accurately touch the specific pins of the voltage output. From the few pins that I had tried, they all turn out to be nil voltage, which is strange because I am still getting the 4 blinks which presumably means there should be some DC output coming out of the power board, is that right?
When I was doing the voltage testing, I placed the black lead (from DMM) to one of the holes in the metal plates behind the circuit boards and let it hang there. Is this the right approach? Are these holes appropriate for "ground". I have seen some youtube videos showing that the black lead should touch the "ground" pin in whatever that I was checking, and I had tried that as well but there were still no voltage in the output pins.
Also, while I was testing the voltage on the pins, there were few instances when the TV will restart itself as if I had physically turn on the switch again. Does anyone knows why this happens? How does me checking the voltage on the output pins will make the TV restart and turn on again? I am very conscious of the fact that there is high voltage involved in the power board so I had been very careful in not touching anything other than using the leads on the DMM.
Sorry for the long post, but I was hoping someone can have a look at the attached notes on voltage distribution and let me know what is the proper way to check the voltage output and whether the results can then narrow down the cause of the problem. In case it is also useful, I have found and also attached a schematic of the power board, but the schematic doesnt show details of the component, so there is no way of knowing the values of the various components, eg. resistance, capacitance etc.
Thank you for your help!
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