Vizio E471VLE No Power

[MarkWilliams64]

I have a Vizio E471VLE that has stopped working all of a sudden.

The Vizio badge that normally glows "Orange or Amber" when the set is plugged in and then turns "White" when the set is turned on no longer lights.

The set does not turn on at all.

My Brother In Law (Electrical Engineer) and former Project TV repairman opened up the back.

On the Power Supply Board (Part # 0500-0405-1340) where the cable to the main board attaches has voltage specs by the socket.
Pins (1-3 are 5.2 volts) we measure 5.3.
Pins (4-7 are Ground), seem to be okay
Pins (8-10 are 12 volts) we measure 0, with an without the Main Board Cable attached.
Pins (11 - 12) are the BL.

On this site another post mentioned jumping Pin 1 to 11 & 12 that the Back Light should turn on and it does.

We also checked continuity on the cable between the Power Supply and the Main Board and it checks out okay.

First Question, should we measure 12 volts on Pins 8 thru 10 if the set is not turned on?
On Pins 8 thru 10, pressing the power button we still measure 0 Volts.

Based on what we've done so far is the Power Supply Board Bad?
Or do we need to do more diagnosis?

Thanks

Mark the The DIY Dad.

[MarkWilliams64]

Re: Vizio E471VLE No Power

Forgot to add, we checked the main fuse and it is not blown.
No obvious failed capacitors or resistors.

[R_J]

Re: Vizio E471VLE No Power

I believe the +12 volts is switched, check the voltage on L220 jumper wire, it should have 12 volts during standby, it is then switched by Q220.
with the main board connected, what voltage do you get on pin 11 and also when the power button is pressed?

[budm]

Re: Vizio E471VLE No Power

"On this site another post mentioned jumping Pin 1 to 11 & 12 that the Back Light should turn on and it does."
Did you disconnect the cable going back to the main board first when you force on the PIN 11 (PS-ON), and PIN 12 (BL-ON) pins? I hope you did otherwise you can damage the main board and that is why I always use the resistors (470 ~ 1000 Ohms) in case it is not done properly.

[MarkWilliams64]

Re: Vizio E471VLE No Power

I hopefully can check what you suggest tonight.
As far as testing Pin 11 and 12, we did use a resistor from my nephews electronics set .
But I can't remember if the cable to the main board was unplugged.

[budm]

Re: Vizio E471VLE No Power

If the cable going back to the main board is not unplugged then the main board will keep the control signal pins low and not allowing the signals to go HIGH.

[JDMRpr78]

Re: Vizio E471VLE No Power

Sorry for bringing up and old thread I have the same set with exact same issue as the OP. I have 5.2 v on 1-3 @ cn201, the rest of the pins nothing. Fuses test good and 60 volts on both sides of f100, cx101 & cx102. Purchased a replacement board from shopjimmy based on diagnosis followed here and exact same issue. So either I got a bad board having same issue or I would assume it is my main board that was the failure.

I did the jumper test discussed above and all backlights come on.

L220 has almost 16 volts(15.86 to be exact).

Any further input on diagnosis?

[JDMRpr78]

Re: Vizio E471VLE No Power

Another pic, power board

[JDMRpr78]

Re: Vizio E471VLE No Power

Shop jimmy replacement and exact p/n board.

[R_J]

Re: Vizio E471VLE No Power

I suspect you have a bad main, If you have +5.2v going to the main board, that should allow the main micro to operate, If it IS working properly, when you push the power button, the P ON/OFF line should change. L220 line could read high when it is not loaded, once the board is turned on, Q410 (switch) will turn on and supply the 12 volt line at 12 volts
I see two fuses (fp1/fp2) on the main board, check them.
It may be an eeprom problem on the main causing the micro not to operate

[JDMRpr78]

Re: Vizio E471VLE No Power

Fp2 has 0 volts at all times, fp1 has 5 volts at all times

[nomoresonys]

Re: Vizio E471VLE No Power

F2 seems blown, simple way to check a fuse, put meter in diode mode, put a probe at each end of fuse, should beep if meter has beep function or read 000. Check both fuses and any other fuses you might see. Fuses if labeled will start with a Fxxx, sometimes they may not look like a typical fuse you might expect to see.

[budm]

Re: Vizio E471VLE No Power

Fp2 has 0 volts at all times, fp1 has 5 volts at all times

You are not going to have switched 12V on that FP2 fuse, that switched 12V will be present when Main board sends PS-ON (P_ON/OFF) to turn on the switched 12V on the power supply board.

[JDMRpr78]

Re: Vizio E471VLE No Power

You are not going to have switched 12V on that FP2 fuse, that switched 12V will be present when Main board sends PS-ON (P_ON/OFF) to turn on the switched 12V on the power supply board.

That's what I was thinking. Is there anything else I can test to verify failure at this point or go with an eeprom?

[nomoresonys]

Re: Vizio E471VLE No Power

Ok, thought you were having trouble telling if the fuses were good or not.

[JDMRpr78]

Re: Vizio E471VLE No Power

Well replaced the eeprom with no luck. Eeprom came from shopjimmy.com. I now have no voltage on 1-12 on the power board.

[R_J]

Re: Vizio E471VLE No Power

So disconnect the plug between the main board and the power supply and see if you get standby (5.1v) voltage on the power supply, I doubt changing the eeprom ic killed the standby voltage, unless you have shorted the pins when changing it.

[nomoresonys]

Re: Vizio E471VLE No Power

Looks like mainboard is not sending ps-on and or bl-on, possible micro issue if so you need a replacement mainboard. Monitor pins 11 and 12, meaning check while tv plugged in but off which is standby take note of voltage then turn on tv take note, report both conditions of both pins here.

[JDMRpr78]

Re: Vizio E471VLE No Power

I said previously that I have zero voltage on any of the 13 pins on power board, I actually have between 5-7 volts as soon as I touch 1-3. It quickly drops to .135v and stays steady. This happens whether the cable from power board to main is connected or not.

[nomoresonys]

Re: Vizio E471VLE No Power

Looks like you screwed something up, you're gonna need one of the guys with LOTS of patience.