e701i-a3 no picture but backlights

[gabe1022]

Re: e701i-a3 no picture but backlights

also now that im pretty sure the t conn is bad my screen doesnt change at all with disconnecting the right side or disconnecting the left side

[budwich]

Re: e701i-a3 no picture but backlights

I don't think you can tell which side is bad by the way the "V" fades (ie. goes right right to left or otherwise) unless you have done the "disconnect corner cable" prior to the test which it appears that you didn't do. I read this from your post... correct if I misunderstand.
Since now you have reported "no V", yes that likely means that the FET is gone.... but you need to do the "power up test" (once you have replaced the FET) with one corner cable removed... other wise you will have done nothing but burn FETS. :-(

[freakaftr8]

Re: e701i-a3 no picture but backlights

That's for sure a short damaging the mosfet

[Jaxley]

Re: e701i-a3 no picture but backlights

First off, great post. Lots to read through, but very informative. Acquired a 70" vizio with no picture. Followed the posts, right side display drivers seemed to be the problem. Detached right side drivers, still no picture. I may have left the TV on for too long with the new tcon in while troubleshooting. I'm getting a short on the "bottom right" pin of the transistor. Here's the question: Replace the TCON again? or just the transistor?

Or: Am I missing something that would warrant a retest?

Background:
70" vizio for free (Pic 1)
previous owner replaced T-Con with no results.
I powered it on when got it home, confirmed no picture (Pic 2)(left it on for more than 4 secs, was before I happened upon this site and wanted to see if I had sound)
Disconnected right driver ribbon
powered on
right side was dim/distorted etc, left side seemed good.(pic 3&4)
reconnected right side, disconnected left side
powered on, blank (no pic)
reconnected both, powered on, blank (dont ask why i thought i magically fixed it)
removed right side driver tabs
powered on, blank
tested T-con Transistor, appears short on bottom right pin(if pin on side by itself is up)

[gabe1022]

Re: e701i-a3 no picture but backlights

So as long as I unplug the tv within 3 seconds it won't fry my tcon or do I basically need to have two tcon's and just plan on one getting fried?

[Jaxley]

Re: e701i-a3 no picture but backlights

Gabe,
Be sure to unhook one side of driver tabs before you power it on with the new board. If you have a multimeter, you can check the new board before installing to ensure it's good. Then if you're super thorough, you can unhook both sides of the drivers, test the voltages on the T-Con(I would say unnecessary if it passed bench test).

If you unhook the right side drivers and get no picture, that's your good side.
If you unhook the right side drivers and get a "weird" picture(see my pictures above). that's your bad side.

and vice versa

[gabe1022]

Re: e701i-a3 no picture but backlights

left side was bad, good to go now

[Kevin Curtin]

Re: e701i-a3 no picture but backlights

Could I just replace the power supply board and the main board and tcon board and have my tv have a picture for my family? The parts will only cost $120 and I know how to replace them.

[Kevin Curtin]

Re: e701i-a3 no picture but backlights

I'm just going to go ahead and get this going with a new thread.

As you all know the Vizio model referenced above as a major failure point. There are other members on this forum including myself they have had failures of the Vizio 70 inch model. It represents itself with it was working fine and then the picture went out but the back light stays on. On at least two occasions including myself replacing the t-con board which is the affected problem just blows the board again. There are repair kits for this t-con which includes a DC converter also EEPROM and a few small SMD transistors. First of all it seems the only transistor that gets taken out is the coxa that is directly connected to the small square SMD style IC to the right of the board. This IC is known as the gamma processor.

To my finding the reason that it keeps blowing this one transistor which is usually the only problem on the tcon board is because of a failed horizontal driver tab on the right side of the LCD panel. It appears that usually only one of these tab drivers fail. With this particular set up the main board does not have the ability to shut down the TV in protection mode like some other manufacturers do. The tcon board and the panel are both made by sharp. The problem lies within the driver IC built into the tab on the panel.

If you have this problem and you order a new t-con board, do not and I repeat do not power up the TV with the new board before you try this first. On the right side of the screen, if you're looking at the back side of the TV then look at the bottom left, you will find a small white ribbon cable that connects the side boards of the panel to the bottom boards of the panel. You want to disconnect the white ribbon cable connecting to the right side board you should see the ribbon cable connector on the bottom of the screen on the side. Just disconnect that small white cable. Now you should be safe to power on the TV with the new board. If what has happened to your TV is correct, you will see the screen presented itself with a nice solid bright picture on the left hand side on the right hand side it will be dark, and possibly a little blurry. However you will see as small section spanning horizontally that looks completely normal. And what I mean by normal is that it's just as bright on the right hand side in this small section as it is on the left. Wherever this lies on the screen is in the same area where you have the failed driver.

Now then I don't endorse this as a permanent fix but if you have given up all odds and you're about to throw this TV out in the trash because you cannot make it work anymore many have tried everything, what I did to Repair mine was carefully peel on the right hand side driver tabs directly clean off the panel. Remember this is only done on the side that is causing the failure. A few have had success with this and some have not. I however had excellent success with it so far.

The reason that the t-con board is shorting out is because this is causing a direct overload to an already subpar t-con board.

This was just my fix and remember if you do manage to pull the tab drivers off the panel this is a permanent thing that cannot be reversed.

I will add pictures in a little bit

Hello, I have recently been granted with the failure of my Vizio 70 inch smart tv. It's the e701i-A3 (but you already knew that &#128521 well my family and I were watching the football game and *snap* (not any noise) out goes the picture. The light is still on in the back of the tv. When I press buttons on the remote it get brighter then goes dark. Took apart the tv. Back is off and I see 3 boards. T-con, main, and PSU. Question is could I just replace these 3 boards because they are inexpensive or will that not work? Please help me, this TV cost $1,500 and I can't afford a new one .

[Jaxley]

Re: e701i-a3 no picture but backlights

All,
Small update. TV is fixed by replacing the transistor on the T-Con board. $.78 and I have 3 extra transistors after replacing the original and previous owner's transistors.

Kevin,
If it's the same issue that this topic focuses on, those three boards being replaced will not fix your problem. You will end up replacing two good boards and frying your T-Con board again. Read through this post, i know it's long, but it's worth it if you want to save money.

[everette]

Re: e701i-a3 no picture but backlights

Hi all. First time poster. Just finished reading the entire thread and am ready to try repairing my TV. Does anyone have a good source to purchase the FET transistors or have extras they do not need?

[nort]

Re: e701i-a3 no picture but backlights

Just an fyi, I just did a repair on one of these 70" LCD sets and it was the LEFT side (as viewed from the front of the set) that was defective.

Also of note, there were NO discernible bright horizontal lines or bars across the screen. After replacing the mosfet on the tcon board and disconnecting left side ribbon, set powered on with a picture. Right side bright and left side darker.

Pulled the left side boards/ribbons off LCD panel and set now has a flawless picture.

[Lyle Beach]

Re: e701i-a3 no picture but backlights

Hello,

I have read through this entire thread 3 times now, and have a good idea what I need to do now. I'm really hoping to get some feedback from freakaftr8 and budwich before I go in for "surgery".

This is a Sony KDL-70R550A model. I have seen that freakaftr8 has fixed a few of these sets. I am pretty sure that I need to remove the drivers from one side or the other, but would like to know which one for sure!

I will attach several photos in an effort to make things clear. But for reference, please know that if I say a "direction" (like left or right) I will ALWAYS be referring to the direction as if you were sitting in front of the VIEWING (screen) side of the TV.

Okay! Here we go!

Picture #1: Showing what the screen looks like with only the LEFT T-con ribbon removed (not at the corner, but at the T-con itself)



Picture #2: Showing that same LEFT t-con ribbon removed



Picture #3: Playing a Blu-Ray movie via HDMI from a Playstation 3 with that same LEFT T-con ribbon removed.



Picture #4: one more or Iron Man playing



Picture #5: So, in this picture, I have Reconnected the Left T-con ribbon to the T-con itself. And now I have removed only the LEFT corner ribbon (circled in RED on picture)



Pictures #5 & #6: These 2 picture are also with the Left corner ribbon removed




Picture #7: This picture is what the screen looks like with the RIGHT T-con ribbon removed at the T-con itself (not the corner ribbon) Just backlights but no picture at all



Picture #8: This just shows that RIGHT t-con ribbon removed (remember, its RIGHT if looking from the screen/viewing side of the TV)



Now then, I don't have a final picture to show you what happens when the RIGHT corner ribbon is removed, because when I did that, the picture showed a quick faint white line... then the picture went completely black, and the TV went into SAFE MODE with the 5 Blinking RED lights.

Thankfully, as previously mentioned in this thread, the Sony and Sharp TV's have a safe mode, so I don't have to worry about blowing out the T-con board.

In conclusion... which side of the TV do the drivers need to be removed from?

Thanks again for all the information in this thread!!!

[budwich]

Re: e701i-a3 no picture but backlights

that's better.... :-)
now the "same thing" has some meaning... I think.
Anyways, I think the "logic" goes like this. When you removed the left corner cable, the set operate as good as it can and gave you a "full picture"... that's because although the left hand cable is no longer get "fed", the drivers on that side of the screen are still "contacting" the panel and "compromising" it to a degree... hence the "less than good picture". When you repeat the test with the right side corner cable removed, now you have taken away the good operating drivers and are trying to make the set only use the left side drivers which are bad. Net result, the tv "errors" out and you get nothing. Hope you follow this.

Based on the pictures, the side that you refer to as the "left" is the BAD side. Those panel tabs need to be removed along that side and only that side. Of course, crossing you fingers and toes is still necessary because there could always be "hidden issues" elsewhere. Further, I think feakaftr8 has indicate that one of the sony's that he worked on died later... potentially the remaining drivers may get over worked. Don't know. All I can add, is that the Sharp panel that I saved is still functioning as "good as new" in my neighbor's house. :-)

One further question. You mention a "faint white line" when you removed the right side corner cable... was the line vertical or horizontal?

[Lyle Beach]

Re: e701i-a3 no picture but backlights

One further question. You mention a "faint white line" when you removed the right side corner cable... was the line vertical or horizontal?

it was a 1/8" thick line that was traveling horizontally from the LEFT side of the screen

[budwich]

Re: e701i-a3 no picture but backlights

that's "good"... if it was a vertical line then it would be potentially a bad vertical driver one of the sides which would not be "saveable".

[Lyle Beach]

Re: e701i-a3 no picture but backlights

So... I removed the left side drivers from the TV and I have "partial" success.

Picture is great on both sides mostly, but there is a big brownish "splotch" towards the right center of the screen. I made darn sure that all the driver ribbons were completely removed from the screen, and tried to make sure that no "remains" of the ribbon was left on the screen. What do you think is causing this defect?

I cleaned all the ribbons with 91% alcohol, and reconnected. When I turned the set back on, I was getting all kinds of weird vertical colored lines on the right hand side of the screen. I guess I didnt get the ribbons seated again properly, because when I adjusted them... I finally got back to where I started with the big "blob" on the screen.

I have attempted to remove, clean and re-install the LVDS cables too. And tried to take the best care possible to make sure they are re-seated properly.

[Lyle Beach]

Re: e701i-a3 no picture but backlights

Looking at my picture above, of me playing Iron Man...

You can still see the big brown "blob" in and about the same area that it still remains.

Perhaps I need to continue to clean the screen where I removed the driver "film" from the screen? I have tried wiping them with alcohol and q-tips. Letting it dry now. Will let you know how it goes. But still awaiting everyone's advice on how to get a clear picture on the whole screen.

Thanks all!

[budwich]

Re: e701i-a3 no picture but backlights

:-( maybe try putting your glasses on and making sure all the ribbon cables are placed properly in the clamps :-)

I am wondering if even though there is some protection mechanism in sharp / sony, maybe it doesn't totally protect everything. I wonder if perhaps the tcon has a problem. Hopefully, someone else has seen this effect. Check the lower interconnection flex cables between boards along the bottom.

something to do with the right side of things as your pictures with the left side tcon cable removed reveals a "clean white half".

[Vinish]

Re: e701i-a3 no picture but backlights

I am having the same problem with a Vizio E701i-A3 as so many others here have described. I closely examined the side panel flexible/film connectors and, sure enough, the tiny little IC in the bottom right (as viewed from the front of the TV) flexible/film connector is dark and clearly burned up.

As others have reported, the COXA transistor on the TCON board is shorted (~0 ohms) from the single pin (black DMM probe) to the bottom right pin (red DMM probe). It looks like I have to replace the transistor or the Tcon board. In the actual orientation of the COXA on the TV, the single pin is on the left of the object and what I have called the "bottom right" pin is actually on the right side of the object and is the top pin. The resistance to the bottom right pin on the COXA is ~1900 ohms.

I don't know if my soldering skills are up to the task but I would like to try that first. Would anyone have a couple of extra left over transistors that they could send to me? I would be happy to pay for them and postage. If so, please PM me and I will give you my address. I am in central Florida.

Thanks, much.

G'day,

Vinish