E701i-A3 T-con failure

[sleepingAwake]

Well here we go.

Picked up a vizio E701i-A3 with no picture but sound works.

Isolated to a defective T-con. Ordered a new T-con off eBay. Installed and had a clear beautiful picture for all of two mins then right back to blank screen.
So to recap. No picture, backlight on, sound works. New T-con worked for a couple of mins and the. Right back to the same fault.

Now I suspect the T-con I purchased was NOS and may have been from defective stock that sharp/vizio sold to some nice Chinese fellows who proceeded to put them on eBay.

So I'm not sure how to proceed.
Is there any way to test for a defective panel? I don't see how the lcd itself would blow the T-con out but I could see how one the panel attachments might have a shorted component or shorted pad if the alignment was poor on those hot barred strips.

Any opinions or suggestions on beefing up the T-con or repairing it?
Once the lcd display was fine for the two mins it worked. No lines or stuck pixels.

[Rasz]

any signs of repair on the "new" tcon?
and start by measuring all the voltages on it

[sleepingAwake]

No signs of repair on the "new" T-Con.

As far as voltages go it's tough to say. I don't have a working part to compare them with.
I've ordered another one from someone else since it was cheap.

The only thing that struck me as odd voltage wise was a lack of voltage on the eeprom. Nothing on vcc.
I would think that should have 3.3v-5v at all times. I don't know exactly which regulator feeds it but vcc is tied to a small 6 pin package and what I believe is pin one on the main processor.

[Rasz]

do you have supply on the connector?  maybe you have broken connector/flex

[sleepingAwake]

Yup. 12v coming in past the fuse.
Sorry should have mentioned that.

There is voltage at other points all over the board.
But since I don't have a point of reference it doesn't really help me.

The eeprom not having anything at Vcc caught my eye.

[Rasz]

http://cdn3.bigcommerce.com/s-thum641i/products/95/images/339/Vizio_E701i_A3_T_con_Front_RUNTK5261TPZH__23864.1405273808.1280.1280.JPG?c=2
?
there are at least 5 fuses on this board

according to this (different model, but might be similar)
http://www.avsforum.com/forum/166-lcd-flat-panel-displays/1458616-vizio-e601i-a3-repair-4.html
there are T-Con-On and T-Con-detect signals, worth checking there out

[sleepingAwake]

Whoa whoa now. Five fuses!!??!!??

Help a brother out here.

The one fuse is obvious on the the T-Con but how do I identify the others?

[OldSchoolTechCorner]

You want to make sure you order the right board as there is a, ZH or a ZE stamp on the T-Con . It more likely not the T-CON, it could be a bad panel, work on this model a few time and know them well. if you were getting One side of the picture is darker than the other, picture has horizontal line, a dark, cloudy spot spreads across the picture, white dots. Don't buy a new T-Con board, will just be wasting money, you just damage the new board within minutes. Now if your audio having issue to, then it a bad BGA on the main board.

Remove the cable to IR board and power it on.

[sleepingAwake]

Audio working good.

Blank screen with backlight on. No horizontal or verticals lines. No splotches or white dots.

Remember a new T-Con worked for two minutes. Original and replacement Tcon had ZH stamp.

[OldSchoolTechCorner]

I do remember one of the fuse was a 5a 32v by right connector on T-CON assuming transistors didn't blow, which happen to these board.

One trick when you get another working T-CON board. only plug in one cable and run it, if it work then disconnect it and run the other half. If it cut out in a few minutes. It's could be a bad panel, or T-CON being disable for a reason. Being it power on and you have audio it passing Self Test. It could be you receive a bad T-Con that was on it's way out, or a bad panel. Could also be lvds cable, but rare.

[OldSchoolTechCorner]

They did a recall on these.

http://hdguru.com/vizio-issues-a-recall-on-large-screen-led-lcd-hdtvs/

[OldSchoolTechCorner]

Rule out power supply as read you are getting the 12v required. You may just got a bad T-Con, won't be shocked could be like you said pulled from another unit. Never had one of these with a bad mainboard, but recall said they had issues with a chip failing that cause the T-Con to be disable. Due to premature failure of a chip assembly sourced from a supplier, this causes the timing control board to be disabled, which disrupts the video signal to the display. You said panel is fine no weird lines, or spots. A bad panel will take out the T-Con board within minutes, but could be something else, as doesn't show the usual signs, so strange issue.

[sleepingAwake]

I'd like to know what the shop jimmy kits include for repair of these Tcon boards.
I can't help but think it would include this "defective" chip vizio warranties.
As I obtained the TV second hand I'm on my own for repair however.

I've thought about disconnecting the panel flex cables one st time as mentioned but at the potential cost of a Tcon board per side I'm hesitant.
First I have to get a new Tcon. 
I was think of leaving the panel disconnected and getting some voltage readings with just the lvds cables connected.

All of this being I'm more interested in the Tcon boards mode of failure and repairing that.

[OldSchoolTechCorner]

The 8 pin eprom that fails on the lower right side. Assuming that more likely what they including and three transistors and the 5a 32v fuse. 

[sleepingAwake]

I've certainly read about the eeprom failing. But I'm not sure what transistors fail on these boards.
I thought there would be an issue with the voltage regulators.

I'll have to post a picture later but a couple of smd caps test at 5 ohms. Every other cap on the board tests 250ohms or much higher.

[Rasz]

I'd like to know what the shop jimmy kits include for repair of these Tcon boards.

Code: [Select]

Access Denied
 You don't have permission to access "http://www.shopjimmy.com/" on this server.google cache says its $15, thats a no brainer price

is it like this http://www.ebay.com/itm/VIZIO-T-con-TCON-Repair-Kit-RUNTK5261TPZH-E701i-A3-E701i-A3E-/130991125476 ?

nice find


check transistors for shorts
there is another fuse mirroring the obviously labelled one, and three green packages that look like polyfuses? two on the fight , one on the left just below big yellow cap, they might be low value resistors tho, im only guessing from the picture

I couldnt find eprom dump anywhere (tv not sold in russia probably ), is it really an eprom? why would there be an eprom on 70' LCD Tcon? calibration?

anyway $15 repair pack sounds like a deal

[sleepingAwake]

Shop jimmy has been out of the $15 kit for some time with no eta on it returning to stock.

The eBay kit is twice the price. I purchased a new Tcon for the same cost.
All of this being said the goal here is still to repair these blown Tcon boards or find the root cause for them blowing.

I've ordered a eeprom programmer and plan on dumping the EEPROM of the new Tcon when it arrives before I install it of course. The 3 green parts with numbers on them are resistors and seem to be ok.
None of the transistors(3pin) seem to be shorted. I'm not sure about the voltage regulators. They all seem to measure in the 1M ohm and up range from between pins.

[sleepingAwake]

Received the eeprom programmer and pulled the bin off of all three Tcons I have.

Here is the checksum for each.

Original TCON board - 80DF
Replacement that lasted 2 mins - 4BB9
New board I got today - 4BB9

Obviously the last two chips have the same code.

So to my disappointment when I received my second Tcon board from a different seller on Ebay I discovered it was another Chinese board.
I was trying to avoid that by purchasing a "used" board from a TV that supposedly had a cracked screen. Once again my suspicion is that once the defective boards were identified any remaining stock was bought by an entity in China and are now being resold on Ebay.

I knew before I installed it that it wasnt going to work. Put it in and sure enough... nothing.

Tcon_On voltage at the psu is 3.3volts btw. Someone had asked prior.

Know lets assume the eeprom units are fine (might not be). Any ideas what to check next???

[Rasz]

is there a voltage on eprom of the third tcon?
I would fix that first
+ get a refund for the tcon

[sleepingAwake]

Nope no 3.3v

I really don't know if there should be a constant 3.3v.
I would assume so based on its function.

[sleepingAwake]

I'm trying to identify the 6pin device IC202 on the board.
It's seems to have U9AU on it. I'm wondering if that's a DC-DC converter.

[That_boy_sammy]

Im pretty sure i just got 2 bad tcons from ebay on this exact model from ebay.  The first lasted for 5 seconds of picture then faded to blank.  I have voltage all across the psu unit. But i don't have any numbers to refer too. At vizparts.com they have tcons recertified for 115$. But is that worthy.

[sleepingAwake]

I got your pm.

No resolution yet.
I'm going to try one of those eBay tcon repairs.
That and maybe putting the Chinese firmware on the original tcon.

[That_boy_sammy]

Next to circuit .100 and 3r3 the numbers are different(lower) on the ebay boards compared to the orginal. I think were on to something.  Ive read numerous pages of hot garbage on google from humans replacing all boards with nothing and calling it a bad panel. Im positive its going to come down to a genuine part.

[freakaftr8]

Hey all. Brand new to the forum. I just acquired one of these TV it has been troubleshooting it no picture condition. I'm really surprised that I went to Target yesterday and found the same exact TV still on sale along with a 60 inch counterpart. I found sharp panels used in very very many large screen TVs. Anyway one of the three pin transistors most notably the one labeled COXA has apparently a short between the center pin to the top right. This transistor operates what appears to be is a 3.3 volt voltage is for the gamma IC processor. I have two of these boards both with the same problem the new one that I ordered I haven't even connected to the panel yet and it was failed from the box. It appears that these boards for previous buyouts from previous failures it has a Chinese label on the back of the board but it came from ebay in the US. I myself am trying to still figure out what's going on I contacted the vendor and they're setting yet another board. I can't seem to locate even in my parts stash thid 3 pin MOSFET with this label. Cox is the equation for the silicon inside the MOSFET it has something to do with the wavelength. This is a really odd transistor. I think its funny how shopJimmy sells this transistor and the EEPROM 8-pin IC. Has anyone successfully repaired this board yet are replacing the components?