Vizio e400i-b2 - Backlight/tv turns on and then off

[heyitzjesse]

Hello

The Problem:
Vizio E400I has no standby light. When you press power button a white light on power button turns on for a few seconds then turns off. The led back light flashes for a second and turns off as well. No picture is displayed at all.

What I did:
Visually checked all capacitors and fuse and all look good.
Tested each individual led strip with a led tester and they are all working ( 28v each strip).
Standby voltage at both pin #1 and pin #2 is 5v.
Ac detect pin#3 is 3.3v.
Ps On pin#4 is not showing any volts when plugged in, but once the power button is pressed it shows me 3.3v.
If I unplug the cord going in from mainboard to led driver and turn on the tv then the led light stays on and tv stays on ( No picture whatsoever)

I am thinking its the main board, or possibly the power board from what I learned following the videos on youtube and the guides on this forum. I am not sure how to proceed from here as I am trying to learn more about board level troubleshooting.

Thank you.

[CapLeaker]

Re: Vizio e400i-b2 - Backlight/tv turns on and then off

sounds like a main board problem. Verify again that the back lights turn on with the main board disconnected and measure all power rails on the secondary. you could also check all the ldo's on the main board.