Vizio V705-H3 Won't power up

[EazyBone]

This TV has the white light on the front. When you click the power button or hit the remote nothing happens the lights stays solid. I checked the main board for the voltage for that signal and everything is fine.

The power supply is giving 13 volts and 2.7 on AC detection. Zero on PSOn and nothing changes when hitting power. The led lines show zero and those caps won't turn on
it seems the PSU won't turn on to supply voltage to LEDs. The main caps sit at 170v.

It's odd to me the led lines go from PSU to main board and THEN to LEDs.. as a note.
I tested all led lines they are all 33-34 volts and working.

I tried to jump the 2.7ac line to PSOn and nothing occurs for PSU (probably not the right thing to do)

Anyone got ideas? I can't figure it if something is wrong with MB signal or PSU..

Thx

[Diah]

this TV operated with Smart Cast. 13V always active at PSU. and you have it. MB are One SoC with GPU build in. need to inspect the MB deeply. USB 5 V 3.3V, 1.8V incase all fine. then you have BGA issue much likely on the SoC

[Storyteller12]

Almost all vizios I come across are bad main boards if it's not backlights. Usually the BGA chips needs reflowing.

on a side note I don't even bother messing with Vizios anymore. There a pain to troubleshoot and nobody really wants to pay for them anymore in my area. So not worth my time

[EazyBone]

Main board was fix. Fortunately only $25.

Tried to reflow but didn't work.

[Diah]

Main board was fix. Fortunately only $25.

Tried to reflow but didn't work.

you need to practice more with reflow... until now i didn't read from yours side you succeed once.

[EazyBone]

I've reflowed about 25x successfully. Maybe I did it wrong but I still don't mind some sort of tip if you have it.. I have a heat gun for electronics and uses flux. Roughly do in circular motion with light pressing .

[Diah]

I've reflowed about 25x successfully. Maybe I did it wrong but I still don't mind some sort of tip if you have it.. I have a heat gun for electronics and uses flux. Roughly do in circular motion with light pressing .

sure
at time you use flux, use cool air pressure to push it round the SoC.
Pressing don't use, i use always car paper painting tape to stick the SoC in place and recover all SMD parts around within 1 Cm distance to avoid any one fly out... use high temperature at time the tape burn brown to black its my sign to stop. when the issue BGA 100% succeed.. but if my BGA judment were wrong the SoC will never being issue so i do trouble shooting the MB again.