Vizio E3D420VX turns off on its own wont start back up

[typenn84]

I have a blasted TV that Ive been troubleshooting for months. It turns off on its own and wont start back up. I have done the whole unplug and hold power button down for 30sec as recommend by vizio but that doesnt work anymore. This has been pissing me off because its intermittent in that if i leave it unplugged for a day it will cut on after that for anywhere between 5 mins to 24 hours.


Ive been T/Sing mines on and off for about 6 months now. I replaced the power supply and it has the exact same issues. I have tried looking for voltage regulators on the mainboard but honestly I cant pick out any except two (up13, up2) and those have the same voltage readings when it work and when it doesn't. They are some other 8 pin chips that might be voltage regs but I honestly dont know.

I am currently looking at the power supply again. I have 2 and they may both be bad. I thought I had bad diodes so I ordered new ones. For the top 2 ,they were measuring around 150 on the diode test, so I assumed they were bad (saw diodes should be between 300-800); this measurement was on both boards. Anywho ordered new ones (8) from digikey and they measured the same thing out of circuit and in circuit. Dont know about you but I doubt that I have 12 bad diodes.
The other 2 diodes on the board that I thought were bad were zenerdiodes. When I do a diode test on them when solder in the board they beeb (measure 0); take them out and it reads 550 or so. So then I got curious and measure the holes on the board without the zener diodes in place and it beeped also, so I dont know if thats normal or not.

I have followed the 2 threads and so far nowhere:
https://www.badcaps.net/forum/showthread.php?t=34441


https://www.badcaps.net/forum/showth...zio+12v+output

With the last one I know the PS is to another model but of note here is that I dont get 12v from the 12V pins without the tv on. If and when it does power up I do get the 12V. Also I tried the resistor between the 5v pin and remote on/off. The power board power up and I read 12v on the pins. However after about 30 secs it cut off ish. All I hear is a rhythmic tapping sound coming from the transformer between the hot and cold side. It wont power back up on subsequent test to power on with resistor, it just starts the tapping and no 12v read on pins (tv has turned back on and functioned since then though).

Mainboard
0171-2272-4314
3642-1512-0150(4)

PowerSupply
0500-0405-1330

I know Im all over the place so any help would be appreciated.

[IHateVizio]

Re: Vizio E3D420VX turns off on its own wont start back up

No Solution, but I have the same problem. Please post a solution here or message me if you figure anything out. My tv has been out of commission for over a year now and I would like to fix it if possible.

[MagicSmoke]

Re: Vizio E3D420VX turns off on its own wont start back up

I know it doesn't help in T/Sing your supply, but for 40$us + shipping shopjimmy has 186 PSU's with that P/N available w/180 day warranty.

If I was w/o my Tv for months I'd go nuts.

I have a PSU/ inverter out of a 32" Vizio I have been trying to diagnose with no joy yet. Finally bought a new one, installed and have a working TV.

BTW pics of board and a description of your sets symptom's will help greatly in helping diagnosis. It could be as simple as capacitor replacement. They can be bad with no visible signs (bulging or leakage) or something more involved.

[typenn84]

Re: Vizio E3D420VX turns off on its own wont start back up

Ok I got the TV working again. I end up buying a mainboard from Shop Jimmy and replaced. Its been about two weeks now and Ive had no issues.

I forgot where I saw it but it said that if this TV had the problems I described it was because the chip got fried or was corrupted. It stated the fix was replacing the mainboard and sure enough, its worked so far. I hope this helps. The mainboard was around 100$ at shop jimmy.