Vizio E70u-D3

[darkfinger]

Re: Vizio E70u-D3

Hi Budwich,

There are no cables in the bottom corners and no side edge boards, only 8 little tabs on each side that stick out about 1/3".

There are 4 boards along the bottom. Depending on which ones are connected to each other I get different effects, shown in the attachments. First one is boards 1 and 2 disconnected, second is boards 3 and 4 disconnected, third is both 1 and 2 and 3 and 4 disconnected.

Thanks,
Dave

[budwich]

Re: Vizio E70u-D3

If you are getting horizontal lines, it is unlikely that you will get a "full picture" without disconnecting the small cables in the bottom corner of the panel on either side. The cables interconnect the bottom edge boards to the side edge boards. If you keep all the cables connected from the tcon to the panel and do the "disconnect one corner cable" at a time, you will likely find one side will produce a complete display while the other will likely get nothing or the tv won't even start up. You can go from there.

PS. I just saw your most recent post. Do the test as I suggest. Anyways, your problem IS NOT a tcon problem. It is a panel problem related to an issue with the tabs on the side of the panel. Post a picture of the display following the test I suggest.

[darkfinger]

Re: Vizio E70u-D3

Thanks for your suggestions!

I've examined the tabs carefully, looking on both sides, with my magnified headset. I can't seen anything that looks suspicious. There aren't any areas that even look strained or sharply bent. I'm puzzled.

There are four long thin boards that hang from the tabs. The inner two are connected to tcon and the outer two are connected via a small cable to the inners. I found that with everything connected the TV reboots, but if I disconnect a single cable (any of the tcon cables or even one of the board-to board cables then the TV stays on. Depending on the configuration of what's plugged in the display shows different things. The best I've got so far is a 3/4 picture, which is better than nothing.

I know you don't think it's likely to be the tcon, but I'm not sure what I should check out next.

[Michale32086]

Re: Vizio E70u-D3

It's likely not any of the connectors that are bad.. It's likely either a TCON or the tab bonds molded to the panel..

Not to be a downer, but it's unlikely anything you did damaged the TCON..

Inspect the tab bonds molded to the panel closely.. Use a magnifying headset if you have one.. I had an issue with a 4K LG that inspection of the tab bonds produced a small burn in the tab bonds..

https://www.badcaps.net/forum/showthread.php?t=70131

That was another heartbreaker...


The horizontal lines, in and of themselves shouldn't be an issue.. One the TV works fine totally, it's likely you can fix the lines issue by pulling off the side tabs on the side where the lines show up.....

But I wouldn't worry about that until you can get a full picture on the display panel..

[darkfinger]

Re: Vizio E70u-D3

Interesting! I did what you suggested, and found that if I unplugged one of the tabs then the TV would partially work, and not reboot constantly like before. The right side of the panel showed a picture which looked pretty good although there were a few horizontal lines through it. The left side was light grey but no picture.

What is strange is that I thought I'd got the problem isolated to that tab. But when I tried moving the tabs onto different connectors the results were inconsistent. For example, swapping the "working" tabs between right and left did not light up the left of the panel.

I can't see any damage on the connectors or tabs, or any strains or bends on the tabs that connect directly to the panel via the left and right boards. I cleaned everything carefully too.

So, I guess I will try a new tcon board and set of tabs. What worries me is those horizontal lines, though - perhaps I damaged the sellophane tabs on the left and right sides of the panel when I was putting the bezel on?

[Michale32086]

Re: Vizio E70u-D3

Thanks for all your advice. I will look at the tabs etc today. Regarding tracking down the problem by disconnecting one tab at a time, is this because one "failing" tab would stop the panel working?

It's possible.. It could indicate a fault in one of the tabs (probably noticeable) or a fault in the TCON (not so much..)

It's unlikely that such a fault is a result of the LED replacement.. I am hoping it's just a mis-alignment of the connector tabs themselves..

[darkfinger]

Re: Vizio E70u-D3

Thanks for all your advice. I will look at the tabs etc today. Regarding tracking down the problem by disconnecting one tab at a time, is this because one "failing" tab would stop the panel working?

[Michale32086]

Re: Vizio E70u-D3

Yep, those are the ones.. Inspect the ends and make sure they are clean and no broken traces.. Then re-insert them into their connectors..

You can also further track down the problem by leaving one disconnected and powering up the TV... do that for each one..

Also, inspect the tab bonds that are molded into the display panel.. Make sure there are no breaks or tears.. Next to a cracked screen, tab bond damage is the biggest danger when removing and replacing the panel. What I usually do is gently bend the tab bond board to the front of the panel and apply a piece of masking tape to hold the tab bonds and board out of harms way..

I kick myself now that I didn't mention it earlier.. I sure hope that's not the problem or I'll feel like doggy doo doo.....

Good luck. I'm pulling for you...

[darkfinger]

Re: Vizio E70u-D3

These connectors?

[Michale32086]

Re: Vizio E70u-D3

I wouldn't have thought so, but there is no telling..

If you can, order the TCON first..

Also, did you make sure that the connections one the large "cellophane" connectors between the TCON and the tab bond boards are right?? They are easy to mis-align which would produce the symptoms you describe...

[darkfinger]

Re: Vizio E70u-D3

Yes, the TV worked fine just super blue tint, prior to my fix.

I've disconnected and reseated all the cables. No change.

I will order new main and TCON boards. Might as well. I feel dumb but confused as to how I could have killed a board. Perhaps static shock?

[Michale32086]

Re: Vizio E70u-D3

Well, I very carefully replaced the bad backlights and put everything back together without a hitch. Felt very good about it, except when I powered the TV back up it doesn't work! The backlight comes on but the screen only flickers - there's no Vizio logo or anything on the screen and no sound. It also appears to reboot itself every minute or so. Bummer. I can't think what I did and there's no visible cable loose or anything. Not sure what to do next.

Can you confirm you have a latent image/vizio logo before you did the backlight fix???

Re-seating all the cables and connections may help...

Otherwise I would suspect a bad Main Video or bad TCON...

[darkfinger]

Re: Vizio E70u-D3

Well, I very carefully replaced the bad backlights and put everything back together without a hitch. Felt very good about it, except when I powered the TV back up it doesn't work! The backlight comes on but the screen only flickers - there's no Vizio logo or anything on the screen and no sound. It also appears to reboot itself every minute or so. Bummer. I can't think what I did and there's no visible cable loose or anything. Not sure what to do next.

[Michale32086]

Re: Vizio E70u-D3

Sounds good..

[darkfinger]

Re: Vizio E70u-D3

Ugh I feel your pain. Thanks for your advice and I hope to be successful. Will post back one way or another.

[Michale32086]

Re: Vizio E70u-D3

hehehe Yea, no biggie..

If it saves the life of ONE screen..

IN this particular case, I did not have those suction devices... I had laid the TV flat with the panel facing down and then proceeded to remove the metal back panel. I left the diffusers and the panel intact on the table..

When I had finished swapping out the LED strips (still amazes me to this day that they were bona fide PURPLE.. ) I found it was impossible to line up everything and put the metal back panel back on the display panel assembly..

So, I set the back metal panel face up, pulled the diffusers one by one and placed them on the metal back panel.. But to place the display panel on, I had to flip it over.. I asked my wife to help me and I think she gripped one of the sides too tight.. I didn't have the heart to tell her cuz I knew she would be really upset about it so I just told her it was my side that had the crack...

Long story short (too late ) I would never have gone that route had I had those suction thingies...

As I said at the time.. Live and learn...

[darkfinger]

Re: Vizio E70u-D3

Thanks. I bought those exact cups from HF! I was planning on lifting the screen from the TV and reversing that on reassembly. I've replaced backlights on a few TVs but nothing bigger than 50". When you cracked the screen did you place the metal back down onto the panel? (and, sorry if I'm bringing back stuff you'd rather forget!)

[Michale32086]

Re: Vizio E70u-D3

Get yerself a set of these:

https://www.harborfreight.com/dual-c...ter-46134.html

I use the dual suction ones for the big screens (60"+) and the single suction ones (off to the right side of the page) for your smaller screens..

They are a god send....

You'll want to be careful when applying suction. Be gentle and slow about it.. I have heard you can crack the screen by applying too much suction too fast.. I haven't done it yet, but it makes sense..

Make sure you have a large work area to allow you to place the screen on a flat area (I use a moving blanket to provide padding) and have another area to be able to work on the TV itself... A quiet area free from interruptions..

Best suggestion I can make is to allot enough time to finish it in one sitting.. Leaving an exposed panel out from the TV overnight invites catastrophe... If you take your time and go slow, allow for about 2-3 hours, assuming you have the correct LED strips already on hand and ready to install.. It's definitely a job you do not want to rush or a have multiple disturbances..

Good luck.. Breaking down a large TV down to the bare LEDs, changing an LED strip and successfully putting it all back together and working perfectly is one of the most rewarding aspects of TV repair..

[darkfinger]

Re: Vizio E70u-D3

Hi,
I've got this exact problem with the same TV and about to go through a replacement of the LEDs. How did you crack the screen? I'm hoping to learn from you and avoid doing the same!

Thanks in advance
Dave

[Michale32086]

Re: Vizio E70u-D3

Final dispo on this..

As I mentioned, I was going to try to fix the bands that did not appear to be associated with the crack and then cover up the crack band and just use the TV...

I had the "brilliant" idea to get some strong tape and put it across the small crack in hopes of preventing the crack from expanding..

The theory was sound.. But I should have did it BEFORE I took it off the wall.. Cracked zipped all the way across to the other side...

Oh well, live and learn.. Hopefully..

Thanx again to all the replies..