Chosen Solution

Model Code: PN42C430A1DXZC TV will not power on. There is no backlight or picture on the screen. There is a standby light on. When I attempt to power on the TV, there are clicks coming from what I think is a relay, the light goes off for about a second, then it is back on solid. No visibly blown capacitors or burnt components on the power supply board. The following are the voltages taken from CN801:

  1. 3.31V
  2. 5.27V 3-12) 0V When i hit the power button #1 drops to .05V, the clicks are heard then back to 3.31V #11 goes to 15.10V, clicks then back to 0V #12 goes to 5.24V, clicks then back to 0V

Update (08/01/2019) T-con board fuse:

Update (08/04/2019) @oldturkey03 Voltage reference for LED driver boards:

SOLVED: Hope this helps someone with a similar issue: I managed to source all replacement parts for this TV . I started to replace parts individually. It wasn’t until the LED driver boards were replaced that a picture came up. As @oldturkey03 mentioned above, better equipment(ie. Oscilloscope) would’ve helped to determine for sure that they were the issue. Unlucky me got to find out that the screen was cracked though. Couldn’t tell by the initial visual inspection that it was there. @oldturkey03 thanks again for assisting.

@myth9 based on the voltages coming from your power board it appears as it is your main board that is not turning the TV on. Remember that it is the main board that tell the power board to turn on. Disconnect the mail board from the power board and try to turn it on. See if you now have the backlight on. Check the T-con board for power as well. You should get 12V on the fuse of the t-con board. Let us know what you find. Update (08/02/2019) Okay your voltages are off and not having power to the T-con board would normally make me replace the power board. Something is definitely off. You have a new main board and a new power board but still have the same issue. In that case the only thing you really have left is the T-con board. That would be an odd error for that but anything is possible. you are certain your replacement main and power board are good boards? You checked all your cables etc., all looks good? You also did not tell us the complete voltages from CN801. Pin 4 Pin 7 Pin 8 Pin 10