Vizio E470i no power

[budm]

Re: Vizio E470i no power

So it has two LED driver circuits for two sets of the string, more likely one string for left edge and one string for the right edge of the LCD panel.
You need to monitor the Anode of the LED string 1 and string 2 to see what DCV you get when you first turn on the TV, I am looking for the Voltage to jump up high and then settle down to the lower Voltage, I also need to know for sure if you do see the backlights flash on for second or not.
BTW, what is the DC Voltage rating of those two filter caps I marked?
Pictures provided by SHOPJIMMY.

[newtothis]

Re: Vizio E470i no power

Off topic but are you female? Just your username indicates it

[AcGeorgiegirl]

Re: Vizio E470i no power

It is confirming what we suspect atm.

Let budm trace the circuits and he will advice you further

Your main is OK btw

You guys are my new best friends

[AcGeorgiegirl]

Re: Vizio E470i no power

...to correct what I last wrote...the logo's fading isn't related to the little blue light fading, as I assumed. I pressed the menu button after the logo gone and blue light gone, and could see the menu on screen with a flashlight. I can now see whatever I put onto the screen with physical buttons(input choices, etc) with the flashlight as long as tv is turned on.

[newtothis]

Re: Vizio E470i no power

It is confirming what we suspect atm.

Let budm trace the circuits and he will advice you further

Your main is OK btw

[AcGeorgiegirl]

Re: Vizio E470i no power

That makes sense.
Ok. The Ps-on and BL-on are at 3.21 and 3.17v with Main connected and after hitting "on" button. The power does come on, but you wouldn't know(no sounds, glow) and for around 5 seconds I can see the "V" logo on the screen, using a flashlight. I've never been able to see this before. I did replace the small-sized fuse on the board yesterday, because I found that it had no continuity. Maybe that's the difference in getting a picture. Also, the logo stayed as long as that proverbial little blue light was lit. It fades to nothing and so does screen. The v's are present as long as it seems the tv is on, even after the 5 seconds of logo showing using flashlight. I tested by hitting the "on" button, and then get 0 v's again.

[newtothis]

Re: Vizio E470i no power

Well there still could be an issue with the mainboard but you should of gotten backlights on from the tests we did indicating an issue.

Plug your main back into the PSU and try switching it on... Observe the BL_ON and PS_ON voltages to see if they rise or not

[AcGeorgiegirl]

Re: Vizio E470i no power

Main is irrelevant to this now.

You have the voltages all coming up yet still no backlight.

Ok, just to clarify for me....the voltages for everything but the 2 standby's aren't there unless I jumper them...so doesn't this mean there's something up with here, as well?...they aren't getting powered through the correct paths(ie)?

[AcGeorgiegirl]

Re: Vizio E470i no power

Yes, that's my board.

[AcGeorgiegirl]

Re: Vizio E470i no power

Are the LCD strings generic, or are they proprietary to the model of the tv? I have 3 other Vizio and 2 Samsung tv's that may/may not be repairable(I'm in the process of taking a look at each). It's a shame how often, though, even the same brand and series aren't compatible in swapping stuff out. Panels, I understand, are pretty much never swappable except exact models, right?

[budm]

Re: Vizio E470i no power

I need good clear pictures of the bottom side of the board to see how the LEDs strings are connected together?
Is this your board? If it is then I do not need the pictures from you.
http://www.shopjimmy.com/vizio-0500-...upply-unit.htm

[AcGeorgiegirl]

Re: Vizio E470i no power

That sounds like trouble for me/my capabilities. Stinks! I did find a replacement set of LED"s, but it's the entire set of strings(12) and the board, so it's not cheap($49). But the other fix would mean replacing the entire panel (including strings and board), right?

[newtothis]

Re: Vizio E470i no power

Nope, Let others see what they think too before getting any deeper.

It involves removing the bezel from the edge of the panel and actually removing the LCD itself from the backlights... Its a very delicate operation and it is so easy to break the panel or bonds. Only then will you get access to the LED strings.... You MAY be able to get a string online... Most likely is you won't and unfortunately there is no markings on the individual LED's themselves so we have no way of knowing what LED to put in (If you can even get them)... To bypass will involve soldering diodes in a string and then soldering them to the pads of where the LED was (Once removed of course)

[AcGeorgiegirl]

Re: Vizio E470i no power

Ok, so if it's an LED string, I'll have to have the schematics for the panel of the tv?

[AcGeorgiegirl]

Re: Vizio E470i no power

Yikes! Bad assumption, huh? I'm once again- a day late and a dollar short.

[newtothis]

Re: Vizio E470i no power

Thanks for the update, Andrew, no worries! Ok, so the consensus is a LED string so far. I'll go do some research...haven't heard that term yet! I guess it's good news that it's most likely not a Main-board issue. I wasted the money on a replacement Power Supply already. Without the schematics, I'm assuming this'll be a guessing game for me to find where this is located, not to mention how to test it. Any ideas how to get Vizio to supply me with the schematics?

Bad LED strings are far from good news!

It involves tearing the panel completely down in an ATTEMPT at bypassing the LED

[AcGeorgiegirl]

Re: Vizio E470i no power

Thanks for the update, Andrew, no worries! Ok, so the consensus is a LED string so far. I'll go do some research...haven't heard that term yet! I guess it's good news that it's most likely not a Main-board issue. I wasted the money on a replacement Power Supply already. Without the schematics, I'm assuming this'll be a guessing game for me to find where this is located, not to mention how to test it. Any ideas how to get Vizio to supply me with the schematics?

[Andrew F. Ali]

Re: Vizio E470i no power

I am so sorry...I mixed up the schematics.....I was looking at a Sharp TV Schematic....Thanks BUDM and newtothis....As for asking many questions, bugging the experts for advice, I think there is no one on this forum who would think this of anyone...I see that you have reached somewhere with the Power board self test...From what I see your Power board is working...and from the reading on CN302...I would tend to agree that you may be suffering from a LED string is 'open circuit' and therefore shutting down the power supply...

[newtothis]

Re: Vizio E470i no power

Main is irrelevant to this now.

You have the voltages all coming up yet still no backlight.

I am sure this is another case of bad LED strings.

Let others pipe in and lets see what they say

[AcGeorgiegirl]

Re: Vizio E470i no power

I also tested the CN302 with the 2 jumpers off. Got a depleting down to nothing reading on all pins that had any voltage before.