Vizio E701i- A3

[drk944]

So I bought this tv a couple months ago and it had a problem with the LCD panel. I fixed the Tcon board and removed the side panel following these instructions: https://www.badcaps.net/forum/showthread.php?t=49281
It worked and I enjoyed my new 70" tv that I purchased for $60.

However two weeks ago I moved a couple blocks and the tv hasn't worked since the move.
I am completely stumped! Here's what I got:
- TV won't turn on whatsoever (tried remote and side button)

- Is there a standby light? I can't remember but if there is, it's not on

- I have standby voltage of ~3.5 Volts (shouldn't it be 3.3) leaving the power supply board.

- It doesn't look like the back lights are on

- After inspecting the cable from the buttons to the main board it seemed like it was kinked and broken (My original thought was it stopped working after the move because maybe I didn't install the cable properly and laying the tv on its back ruined the wire?)

- In testing I ran a jumper wire, with the cable still in, from the pin on the main board to the button board. (on the side of the supposedly broken wire inside the cable). Doing this caused the speaker to start popping a little for a sec until I moved and lost the connection.

- I think I accidently touched the wrong leads (pin 1 main board jumped to pin 2 on button board) the 2nd time around and it started lightly sparking on the buttons board. I realized what I was doing was probably dumb and stopped.

- I purchased a new cable to run from the main board to the buttons and am still having the same issues

- The whole time when the tv is plugged in, there is an electronic whining noise. It appears to be coming from somewhere on the power supply board, but I can't pin down the exact location. Whining noise becomes a lot quieter after unplugging the main board.

I need some help, my wife isn't to fond of buying another tv, especially not anything expensive after I impressed her with how cheap I got this one for. And I'm not ready to start replacing boards willy nilly yet because it seems like I can't find a main board that isn't cheaper than $150

Thank you!

[nomoresonys]

Re: Vizio E701i- A3

Throw up some good clear straight on pictures of each board and one of the whole back to see how they are all connected, try test number 3 below, try to do it just as instructed ala pin name/description pin number and voltage both in standby which is plugged in but not powered on and then when powered on.

[drk944]

Re: Vizio E701i- A3

Ok I did what you asked and this time with a nicer voltmeter, I'm not sure what you meant by "ala pin name/description pin number" but I measured pin 1 on the power supply board that is labeled "3.3v" that connects to the main board and I read 3.33v on standby. When pressing the power button or using the remote, nothing changes whatsoever and I still read 3.33v. No new sounds or anything when attempting to power it on.

Attached are some images of the boards and the whole tv. Let me know if you would like more/ better pictures.
Thank you!

[dick_barton]

Re: Vizio E701i- A3

You need to measure all the voltages on CN201
Pin 1 Name = yyvolts
Pin 2 Name = xxVolts
Pin 3....
Pin.....
Pin 15 Name = zzVolts




Where is the ribbon cable end for the second connector. I can see the blue tab but not the ribbon attached to it?

[drk944]

Re: Vizio E701i- A3

The 2nd ribbon cable from the buttons board goes to the IR board that is positioned towards the front of the tv (see picture)

Here's what I got for CN201 during standby:
#: Volt Label:
1: 3.3 3.3V
2: 3.4 AC-DET
3: 3.29 PS-ON
4: 12.2 12V Audio
5: 0 GND
6: 0 GND
7: 0 GND
8: 12.2 12V Reg
9: 12.2 12v Reg
10: 3.26 BL-ERR
11: 0 LED-ON
12: 2.57 LED-BR
13: No Cable
14: 0 12V T Con
15: 0 t Con_On

Pressing the power button does not change the voltages on pin 14 or 15

[budwich]

Re: Vizio E701i- A3

black light fault / failure. potentially running the set too bright. Looks like you will need to do some work. Others will tell you how to check for failures with a meter to confirm.

[dick_barton]

Re: Vizio E701i- A3

There's a few missing voltages
Pin 11 (Led_ON) = 3.5V (approx) to turn the backlights on
Pin 15 (Tcon_On) = 3.2V (approx) which should switch 12V to Pin 14 (12V Tcon)

However it could well be a led issue as budwich says. Can you measure the voltages at the led connector pins when you press the power on button and see if the voltages spikes to a maximum before dropping.

[nomoresonys]

Re: Vizio E701i- A3

Yep, looks like a backlight issue, "10: 3.26 BL-ERR
11: 0 LED-ON"

[drk944]

Re: Vizio E701i- A3

Ok I'm not sure what you meant by led connector pins. Were you referring to: BL-ERR, LED-ON, and LED-BR?
If so I measured each of those from standby mode and pressed the power button, there were no power spikes. Is there somewhere else I should check?
Have we narrowed it down to the backlights? Does that mean I'll need to follow this shop jimmy tutorial in order to replace them? https://www.youtube.com/watch?v=ocyE...=ShopJimmy.com

Thank you for your help so far

[nomoresonys]

Re: Vizio E701i- A3

No, the connector for backlights is CN301, that's the one you want to check the voltage of.

[drk944]

Re: Vizio E701i- A3

Ok, I checked the voltage of all the connectors of CN301, and read 0.0V, no power spikes upon pressing the power button. Any idea where I should go from here?

[dick_barton]

Re: Vizio E701i- A3

Just found this in another post on this model so it looks like the backlight voltages cannot be measured with your meter.

Posted by Budm on this model

From looking at the outputs that go to the LEDS, it looks like it will not be steady DC but pulsing DC output at high frequency with pulse width modulation. So if you use DC meter to read those outputs, it will not show correct DC voltge.

[dick_barton]

Re: Vizio E701i- A3

Disconnect the mainboard from the power supply and use a 1K resistor between CN201, Pin 1 (3.3V) to Pin 11 (Led_On) and see if the backlights come on.

If they do then connect the 1K resistor from Pin 1 (3.3V) to Pin 15 (Tcon_On) and see if you have 12V at Pin 14 (12V T Con)

[nomoresonys]

Re: Vizio E701i- A3

Ah I see, nice find Dick.

[drk944]

Re: Vizio E701i- A3

Ok, I placed a 1k resistor between pin 1 and 11 (LED-On) and there were no back lights. So does that mean we've narrowed it down to it being a back light issue?
Some coincidence that my back lights go out while moving...

[dick_barton]

Re: Vizio E701i- A3

Did the Tcon_ON 12V come up when you tested that?

From quotes from a previous post

Hi, I'm new here. What brought me is I have a E701i-A3 that crapped out on me last night.
Picture froze and then slowly faded to black. LED backlight works. Audio works. I can adjust the volume, and I can navigate some things from memory..........

Next the voltages at the connector was tested

T CON_ON: 3.2V
12V T CON: 12.2V
NC: No Cable
LED-BR: 2.8V
LED-ON: 3.2V
BL-ERR: 0V
12V REG: 12.29V
12V REG: 12.29V
GND
GND
GND
12V AUDIO: 12.29V
PS-ON: 3.3V
AC-DET: 3.4V
3.3V: 3.3V

And confirmation once again that the backlights were definately on

The LED backlight is definitely on..........

In your Post #5 it shows 10: 3.26 BL-ERR so it maybe that a led connector or led connection has loosend or become ajar. when you moved.

[drk944]

Re: Vizio E701i- A3

Yes I read 12v from pin 14 when jumping pins 1 to 15. Does BL-ERR stand for "Back Light Error"? Would you recommend getting some suction cup tools and pulling apart the TV to inspect the LED strips?

[dick_barton]

Re: Vizio E701i- A3

BL-ERR is backlight error.

I'm not 100% certain if it is a led problem or a fault on the power supply board not switching on the led driver circuitry.
Perhaps someone else can offer advice at this point.


What concerns me is that you say that this only occurred after moving the set so I cannot see why any led would fail.
Have a look through Youtube for videos of lifting the screen using suction cups and of course be very careful that you reseat the panel carefully so that it's not damaged when being re-assembled.


Post #19 may be of interest to you
https://www.badcaps.net/forum/showth...t=e701i-a3+led

[drk944]

Re: Vizio E701i- A3

Great, thank you so much! I ordered some suction cup tools to open up the screen, I'll inspect it this weekend and post back my findings then. Thank you so much for your help so far and I hope I can get this thing working again!

[drk944]

Re: Vizio E701i- A3

Well, I tore it down to the frame, and I can't find what's wrong with it. Last night I picked up a 55" for $40 that needs a small repair done to it, so instead of throwing money at this vizio I'm just going to toss it. Thank you for all your help. Are any of the boards worth selling? I'm not sure if I could because I have no idea if they're what's at fault though.