Vizio E3D420VX No picture, Power light blinks on then no power

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Hey everyone, I replaced the power supply board as suggested, but that didn't fix my issue. What should I do next?

My problem was different. For me, only the white power LED blinked for a few seconds and then turned off. The screen never showed anything.

This sounds like my issue. So far, a new power board hasn't solved the problem.

[robhink]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

My problem was different. For me, only the white power LED blinked for a few seconds and then turned off. The screen never showed anything.

[djju]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Hi! I have a symptom in Vizio E3D420VX TV
1. Press power button, power white light on and Vizio V logo is on the screen
2. Logo goes off, power white light blink one time.
3. Power goes off by itself and doesn't come up
4. Same symptom in every time when I press power button.

Is it an exactly same symptom as you?
Can it be solved by replacing the power board?
Or, do I have to replace the main board???

[djju]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

FIXED!!!

I spent $32 on a new power supply board from Shop Jimmy and it worked! And while I'd love to know which specific component on that board failed , I'm pretty stoked. I got this TV free from a friend who didn't want it when it quit working. Vizio didn't want to pay to fix it so they just refunded him his money.

WOO HOO!!!

Hi! I have a symptom in Vizio E3D420VX TV
1. Press power button, power white light on and Vizio V logo is on the screen
2. Logo goes off, power white light blink one time.
3. Power goes off by itself and doesn't come up
4. Same symptom in every time when I press power button.

Is it an exactly same symptom as you?
Can it be solved by replacing the power board?

[robhink]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

FIXED!!!

I spent $32 on a new power supply board from Shop Jimmy and it worked! And while I'd love to know which specific component on that board failed , I'm pretty stoked. I got this TV free from a friend who didn't want it when it quit working. Vizio didn't want to pay to fix it so they just refunded him his money.

WOO HOO!!!

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Okay, I did the test as described. The backlight came on for about a second when I pressed the power button, but then it shut off. No pictures or images showed.

[robhink]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

I'm having the exact same problem with my E3D420VX. Was a solution ever found? Should I just replace the main board or power supply board?

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

PS-ON did jump higher than 1.3V at first.

What other info can I provide you with?



Do you still want me to do this test?

Yes.

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Thread bump. What's the next step I should take in this repair?

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

PS-ON did jump higher than 1.3V at first.

What other info can I provide you with?

You can force on the backlights by remove the wire of the pin 12 (ON/OFF) pin first (you must do this because we do not want to back feed the forced Voltage back to the main board) then use a 300~1K Ohms resistor 1/4 W between the 5.1VSB pin and the pin 12 on the board. Plug the TV into the outlet and see you can get the backlights on and see the pictures on the screen if the main board and the T-CON boards are OK.

Do you still want me to do this test?

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Doesn't this mean that the PFC circuit is going into protection shutdown?

If so, could this be due to the low (?) PSON voltage?

OK, I re-read his reply again and understand his measurement now.:
Plugged in and turned on:
Neg terminal to ground: jumps to -54
Pos to ground: 331 at its highest, then goes down
Neg to Pos: 392, for a second

Now we need to find out if the PS-ON did jump up higher than 1.2V first or not.
The switched 12V should also drops out since the same PS-ON is used to turn on the 12V switched MOSFET Q910.

[fzabkar]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Readings for the main filter cap, what I assume is the biggest cap, C804.

Neg to Pos: 392, for a second

Doesn't this mean that the PFC circuit is going into protection shutdown?

If so, could this be due to the low (?) PSON voltage?

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

OK, the PS-ON from the main board is OK otherwise you will have the boosted Voltage to run the backlights inverter section, but the main board is not sending the BL-ON signal to turn on the backlights inverter circuit.
You can force on the backlights by remove the wire of the pin 12 (ON/OFF) pin first (you must do this because we do not want to back feed the forced Voltage back to the main board) then use a 300~1K Ohms resistor 1/4 W between the 5.1VSB pin and the pin 12 on the board. Plug the TV into the outlet and see you can get the backlights on and see the pictures on the screen if the main board and the T-CON boards are OK.

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Thanks for clarifying! The DCV for that reading is 392.

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Black probe on the negative leg of the cap, Red probe on the positive leg of the cap then check the DCV when the power switch is activated, make sure not to let the probes slip on you and do not touch anything withe your hands/body, you are working in the deadly side of the circuit.

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

My post 6 instruction:
You need to check DCV between the two legs of the main filter cap to see if it has close to 400VDC or not.

I apologize for not understanding.

What do you mean by checking the DCV between the legs? I understood that to mean "make contact with both legs and measure the voltage," but I'm sure I misinterpreted what you wrote. Are you saying that the multimeter shouldn't make contact with the legs? Just looking for clarification before I take another reading. Thank you.

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

My post 6 instruction:
You need to check DCV between the two legs of the main filter cap to see if it has close to 400VDC or not.

[retiredcaps]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Readings for the main filter cap, what I assume is the biggest cap, C804.

Plugged in but not turned on:
Neg terminal to ground: -62.7
Pos to ground: 97.3
Neg to Pos: 163

Plugged in and turned on:
Neg terminal to ground: jumps to -54
Pos to ground: 331 at its highest, then goes down
Neg to Pos: 392, for a second

On the hot side , the negative leg of the large filter capacitor is your ground.

[tannenbaum]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

Readings for the main filter cap, what I assume is the biggest cap, C804.

Plugged in but not turned on:
Neg terminal to ground: -62.7
Pos to ground: 97.3
Neg to Pos: 163

Plugged in and turned on:
Neg terminal to ground: jumps to -54
Pos to ground: 331 at its highest, then goes down
Neg to Pos: 392, for a second

[budm]

Re: Vizio E3D420VX No picture, Power light blinks on then no power

"Pin 12 (ON/OFF): 0.026" The main board is not sending the BL-ON (Inverter ON) sinal turn turn on the backlights circuits.
You need to check DCV between the two legs of the main filter cap to see if it has close to 400VDC or not.