E701i-A3 T-con failure

[OldSchoolTechCorner]

Added this one to the long list of crap design LCD TV's and monitors I seen over the years, that have this exact issue. No metal frame and no clip and thermal pad to push on those chip on film drivers. Built to a cost and design to fail 

[freakaftr8]

Guys it worked it freaking worked perfect picture?!!

And I don't even understand how. I completely removed the right-hand tab drivers from the right side of the screen completely remove them off the screen carefully peeling them away from the lcd and unplugging the two side connector boards from the bottom of the panel and it has a perfect picture!! I have many pictures but I don't know how to post them on here. Essentially the left hand in the right hand tab drivers are both medium duty cycle now that I remove the right side and the left hand side is working harder most likely. There is a very small 1/16 inch segment all the way on the right side of the screen that doesn't show anything vertically from top to bottom I don't know if this was part of the problem or not but it's very barely noticeable. I would suggest getting a good tcon and only connecting one side of the time very promptly powering the TV up and watching for the V in the center of the screen if you have one on one side but the other side is dark and blurry unplugged the TV right away note which side is messing up and this will tell you which of the tab drivers are bad on that side of the panel

[freakaftr8]

I would like to know that all I did to the t-con was replaced the coxa driver like I mentioned in a previous post. I did some other things but those were mess ups of my own failure but that's all that shorts on these t-con board taken down the T CON voltages. Same thing happens when one side of the panel shorts it momentarily disrupt the t-con voltage signals in left unchecked it will blow the T CON eventually

[freakaftr8]

Well almost perfect picture it seems on a all grey screen it seems to have a problem trying to omit light through the panel on the bottom center like on this Netflix screen

[OldSchoolTechCorner]

Well almost perfect picture it seems on a all grey screen it seems to have a problem trying to omit light through the panel on the bottom center like on this Netflix screen

At least you got it to the point of being useable, rather then end up in the landfill and parted out. Still great progress . 

[sleepingAwake]

How is the refresh rate?

And instead of peeling off the hot barred ribbon cables could you have just disconnected the ribbon cables that are designed to be removed from the side boards???

[freakaftr8]

Refresh rate is absolutely perfect the screen looks as if there's absolutely nothing wrong with it except for a little bit dark in the bottom center just ever so slightly though it really presents itself on a gray background though

, I originally tried just disconnecting the power to the side driver boards and what that did was presented a very dark image on that side which was very slow motion and blurry 2. The only reason I figured that the side tab drivers on that side were having problems is because when I first connected the t-con board one side at a time one side I had a good picture the other side started flickering and then it cut out so I knew there was a problem on that side first. After that with the one good side connected on the tcon to the panel I realize that there is a white strip that did not seem to be affected on the screen even though the other side was not connected off the tcon.  I realized that there was a problem with the tab driver in that section and on this particular panel if one of the tab drivers are not making a good connection you'll have a strip on the screen that looks perfect but the rest of the panel will be dark and blurry on that same side where it is disconnected from the t-con board. That's how I knew that when I started pressing on the tab the good strip section would start to get dark and blurry like the rest of that side of the panel essentially there was a short in that section then when I pull that off the panel I had a perfect area working so that's why I removed all the drivers off the right side.

Now the left side is doing all the load that the left and right were doing at the same time so the score I don't know if the panels going to last too long but it's still working perfect. But hey if you got no other alternative and you know that it's going to meet the junkyard give it a shot its worth it

[freakaftr8]

I almost forgot to add the tcon board I repaired is my original t-con board the other boards I got off of ebay that came from China will not function at all.

So is anybody bold and daring enough to try what I did?

[sleepingAwake]

Maybe if you could include some pictures of where you removed the ribbon cables and the end result.

You'll probably have to put them on imgur or photobucket. This sites 1000kb restriction on attachments isn't exactly picture quality friendly.

[freakaftr8]

I can do better check out this site somebody else is having the same problem on a sharp. I've been dealing with this last night with them too. I go by the same username there also can I have pictures posted..

This will hopefully give you a better understanding of what needs to be done

http://www.badcaps.net/forum/showthread.php?t=48477&page=3

[sleepingAwake]

Wow. Okay well after I repair yet another TCON I'll give it a shot.

[freakaftr8]

I wish you luck. I just want everybody to know that this is a last ditch effort resort to try to repair the panel I would do this if you're giving up the ghost and ready to throw in the recycle bin because once you pull these ribbons from the panel carefuly peeling them away you are inevitably changing the panel properties and you can never go back.

Remember as for the t-con board technically the only problem I have found is the Cox a transistor shorting and I used a substitute replacement shown in a previous post.

Now I would not go peeling ribbon connectors off the panel unless you're absolutely sure that one side is shorted by testing the t-con board 1 ribbon connection at a time and looking for the V to come on screen upon power up one side if there is a problem will be darker and the panel will after a few seconds cut out two black so all you can see is a backlight. If this happens immediately unplug it do not leave it plugged in as that is what causes the t-con board to short out. Another way to tell if your side drivers are bad is to unplug the ribbon cable that Carries from the bottom of the panel to the side driver boards therefore you can leave both ribbon cables connected to the tcon board but the screen will be dark and slow to refresh.

I did noticed in your first post sleeping awake that you said you had a perfect picture for a few seconds. If you had a perfect picture I'm not sure if you have the same problem as I do. Are you sure that one side wasn't darker than the other? The TV literally takes 5 seconds or so to go from the V upon power up to an actual image. In that time if there's a short on the side drivers the board will already shut down in the screen will go blank. This was my trial and error to determine it was a side driver

[That_boy_sammy]

So once that tab driver is removed another cannot be replaced with it?

[freakaftr8]

No. These drivers are bonded to the panel at the factory and are not technically made to be removed.

[sleepingAwake]

Yeah I'm wondering if the panel is screwed up in a worse way. When I repaired on of the non-china stamped TCON's I didnt get a picture.
That TCON had proper voltages for a short period of time before blowing. But no pic the whole time.

I wont buy one of those repair kits again. Instead I'll try to source the individual parts from Digikey or some other US supplier.
Its cool that Aliexpress has the components but I'm not keen on waiting a month for shipping. I either want this thing fixed or recycled within a couple of weeks.

[freakaftr8]

That TCON had proper voltages for a short period of time before blowing. But no pic the whole time.


That's probably because the panel immediately took down the T CON with a short so you didn't see a picture. You have to look really quickly as you the power of the TV up for the V in the center of the screen. If there's a problem it'll fade away quickly but you'll still see voltages at the tcon even though the panel shorting it at the moment

[sleepingAwake]

Well actually I saw horizontal staticky lines for a brief second when I first powered it on.
Not sure how terrible that is.

That being said. Do you think I could substitute one of the XOSV fets for a COXA?
XOSV has a lower voltage rating but higher amperage.
I'm just trying to come up with ways to use the donor parts I have laying around.

[freakaftr8]

I'm not sure about the substitution because I believe that is a NPN style transistor. What you're needing is n channel MOSFET 45 volt 2 amp or higher.

The horizontal staticy lines sound like it's a dead giveaway of being a bad side tab driver

[sleepingAwake]

My dc-do converter is blown. All of them. Lol

I guess I will have to wait. Digikeys minimum is 3000

[freakaftr8]

 well i can sell you my repair kit what comes in a few days. I'm not going to need it now.

Btw been on straight since repair last night.

[sleepingAwake]

Well I could order a bunch of fets and the dc-do converters from China and just wait.
I can get 30 of each component for $22 total.

The idea of paying another $25 for $1 worth of ICs doesn't sound great.
Unless your selling it cheep cheep
I think I've dumped about $80 into this stupid tv.


Oh and the blank EEPROM that I thought would be written too upon power up was still blank.
Yet another reason I probably didn't see a picture.

Needless to say I flashed it with a copy of the correct code earlier today.

[freakaftr8]

SleepingAwake,

My DC converters seem OK. Ill send you my two boards if you want them. Also Ill try to locate another replacement COXA equivlent in my stash and add that into the envolope.. Let me know.

Pm me your address, you can have for free.

Acuually I will do one better.. I will take my board that just has a blown COXA. Ill put my QF SOT23 on it and bench test it to make sure it works, then ill send it to you, no cost.. Just want to see someone else be able to do what I did..

[sleepingAwake]

Thanks man. You rock.

I need to get a current limiting psu so I don't blown the thing up when I connect it.

[freakaftr8]

Hey SleepingAwake did you receive the board yet?

Remember try to keep your hand on the.plug if the screen starts to flicker. Then try the other side.

[sleepingAwake]

Nah not yet.

Frankly I'm scared I'll blow the thing up faster than I can unplug it.