VIZIO E70-E3 Half picture with half TCON

[Fly_Among_Stars]

Hi,
I have a VIZIO E70-E3.
Symptoms: Black screen, no picture, but LED backlights are working.
I probed the power board and voltages are as listed on the board.
Main board appears fine, too.
I believe the problem is either a bad T-CON board, or connection to LCD, or bad LCD.
There are two separate ribbon cables feeding the LCD.
If both are connected, the screen is black.

If only the ribbon cable that feeds the right side of the screen (when viewed from the front) is disconnected, the left side of the screen shows picture and the left side shows all white. The reverse is not true, screen stays all black.
I probed the test points on the TCON board under the ribbon connectors.
On the TCON board left side (feeding the screen), top row pretty consistently was reading 0.6V and bottom row was reading pretty consistently 1.1V. (I think one or two points, maybe the 4th and 8th read the same as each other)
When I probed the right side, the top row pretty consistently was reading 100 mV and the bottom row was pretty consistently 1.6V.

Additionally, the row of 3 caps at the bottom center of the board under D307, read shorted. (They are caps, right? No values printed on them, and the other parts like those didn't read shorted.

Finally, I already ordered a new TCON board, but same problem of a black screen. I know I read the same shorts, but I don't remember if I got the same readings on the test points under the ribbon cable connectors.
Therefore, I'm worried the problem is causing TCON board problems, or it is downstream of the TCON on the boards/ribbons feeding into the LCD. I have not fully pulled back the bezel to do any voltmeter probing there yet.


Ideas?
Thanks, it was reading previous posts on this forum that got me to this point.

[ajshoe]

Re: VIZIO E70-E3 Half picture with half TCON

side tab removal -search "vizio E60-E3 backlights, sound, no video"

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

I was going to try the tape trick next, but wasn't sure it was worth it if given the way the voltages on the board were dissimilar between the two sides.
But I also wasn't sure if a problem downstream was why the voltages were different. Cause or effect?

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

I think I read that one. I was hesitant to go that route right away because it's permanent and I wasn't sure it was exactly my situation.
I wanted to understand if there were other options to explore first...and I'm not feeling that confident about ripping stuff yet. It feels like a big step.

[nomoresonys]

Re: VIZIO E70-E3 Half picture with half TCON

Yes it's permanent, test a little more, you want to unhook all the cables from the tcon and retest those little mlc caps again, they are caps and should not be reading short, how exactly are you testing them?

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Probe on either end of the caps, the silver ends.
When probing the test points, I had negative lead on a screw and positive end in test point.

[nomoresonys]

Re: VIZIO E70-E3 Half picture with half TCON

Ok, if you didn't test those caps in ohm mode go ahead and do it, do some of the others on the board that are not shorted, that should verify your results, you can also check in beep mode, with neg. probe on ground screw and positive on each end, one end should beep/show continuity, the other end should not.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Those caps measure around 6.8k ohm with power off. And in beep mode, negative probe on screw, beep on bottom lead. But apparently all the caps beep on one side when negative probe is on screw.
And while power is off, those caps are not short, they don't beep if measuring across top and bottom leads.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Okay, so this is unexpected. I only get a beep, short, when the negative probe is on the top and positive on the bottom. But only for those three caps. If I reverse the probe ends, no beep.
Other caps on the board do not care which probe end is on the right or left or top or bottom.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

And they're measuring 3.2V. sorry for not doing that first to verify and make us chase a red herring.

[nomoresonys]

Re: VIZIO E70-E3 Half picture with half TCON

Ok, seems like they are ok, it is funny about only beeping in that one direction, is it a long beep, short beeps are usually nothing.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

It's a long beep. I do get short beeps on the others, but I disregarded them.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Any thoughts on the different voltages I measured on the test points under the two ribbon connectors?

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

I've been trying the taping method and really want getting anywhere.
I don't know what pins I should tape, how many at a time, and what side to start from in the ribbon cable.

I pulled off the bezel, and noticed the LCD board is split in two. Simply disconnecting one half results in only 1/4 screen white! Getting closer.

So then, I applied a small piece of tape on that connector and got almost a full image but with distortion.

Question: is it okay to perform the tape on that connector? Or is it preferred to do it only on the tcon board ribbon?

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Update
I found that if I taped pins 9 and 10 on the U-Ribbon I can consistently get a full picture. If either of those pins are not covered, the screen is black.
Unfortunately, as can be seen in the images, it wasn't the only problem.
I noticed that slight pressure on the right side affected the horizontal lines, so I pulled back the bezel on the TV screen's right side and noticed that those side tabs were smashed in half and that the screen wasn't fully taped down cleanly like it was on the left side.
I attempted to unroll the smashed side tab and the horizontal lines went worse.
You'll also notice in the images that the screen's left side is significantly more washed out (brighter).
And two pictures I attached aren't duplicates, it's to show that top right, as the show ads came up, the top right side would fade back to dark.

[Fly_Among_Stars]

Re: VIZIO E70-E3 Half picture with half TCON

Bump!
I'm still interested in hearing your ideas and suggestions on what to do next.
Thanks.

[Diah]

Re: VIZIO E70-E3 Half picture with half TCON

you may have LCD glass at the bottom some where broken.. by removing Bezel you can inspect it carefully