E701i-A3 T-con failure - Page 1
Forum section: electronics / repair

author: sleepingAwake
author_rank: Contributor
timestamp: August 21, 2015, 06:15:33 pm
content: 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.

author: Rasz
author_rank: Super Contributor
timestamp: August 21, 2015, 09:28:36 pm
content: any signs of repair on the "new" tcon?and start by measuring all the voltages on it

author: sleepingAwake
author_rank: Contributor
timestamp: August 21, 2015, 09:51:51 pm
content: 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.

author: Rasz
author_rank: Super Contributor
timestamp: August 22, 2015, 12:46:36 am
content: do you have supply on the connector? maybe you have broken connector/flex

author: sleepingAwake
author_rank: Contributor
timestamp: August 22, 2015, 12:55:17 am
content: 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.

author: Rasz
author_rank: Super Contributor
timestamp: August 22, 2015, 02:20:17 am
content: 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 boardaccording to this (different model, but might be similar)http://www.avsforum.com/forum/166-lcd-flat-panel-displays/1458616-vizio-e601i-a3-repair-4.htmlthere are T-Con-On and T-Con-detect signals, worth checking there out

author: sleepingAwake
author_rank: Contributor
timestamp: August 22, 2015, 02:25:08 am
content: 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?

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: August 22, 2015, 04:19:20 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: August 22, 2015, 04:33:06 am
content: 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.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: August 22, 2015, 04:59:20 am
content: 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.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: August 22, 2015, 05:08:03 am
content: They did a recall on these.http://hdguru.com/vizio-issues-a-recall-on-large-screen-led-lcd-hdtvs/

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: August 22, 2015, 05:20:07 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: August 22, 2015, 05:53:51 am
content: 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.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: August 22, 2015, 05:59:30 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: August 22, 2015, 04:53:50 pm
content: 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.

author: Rasz
author_rank: Super Contributor
timestamp: August 22, 2015, 11:14:39 pm
content: Quote from: sleepingAwake on August 22, 2015, 05:53:51 amCode:Access DeniedYou don't have permission to access "http://www.shopjimmy.com/" on this server.google cache says its $15, thats a no brainer priceis it like thishttp://www.ebay.com/itm/VIZIO-T-con-TCON-Repair-Kit-RUNTK5261TPZH-E701i-A3-E701i-A3E-/130991125476?nice findcheck transistors for shortsthere 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 pictureI 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

author: sleepingAwake
author_rank: Contributor
timestamp: August 23, 2015, 02:01:03 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: August 25, 2015, 04:04:31 am
content: Received the eeprom programmer and pulled the bin off of all three Tcons I have.Here is the checksum for each.Original TCON board - 80DFReplacement that lasted 2 mins - 4BB9New board I got today - 4BB9Obviously 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???

author: Rasz
author_rank: Super Contributor
timestamp: August 25, 2015, 07:43:22 am
content: is there a voltage on eprom of the third tcon?I would fix that first+ get a refund for the tcon

author: sleepingAwake
author_rank: Contributor
timestamp: August 25, 2015, 12:52:11 pm
content: Nope no 3.3vI really don't know if there should be a constant 3.3v.I would assume so based on its function.

author: sleepingAwake
author_rank: Contributor
timestamp: August 25, 2015, 03:40:49 pm
content: 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.

author: That_boy_sammy
author_rank: Newbie
timestamp: September 06, 2015, 04:09:26 pm
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: September 06, 2015, 04:22:38 pm
content: 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.

author: That_boy_sammy
author_rank: Newbie
timestamp: September 06, 2015, 05:14:32 pm
content: 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.

author: freakaftr8
author_rank: Contributor
timestamp: September 07, 2015, 01:25:28 pm
content: 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?

author: freakaftr8
author_rank: Contributor
timestamp: September 08, 2015, 03:32:58 pm
content: My new board should be here today. I'm fully expecting it to be bad. I however did remove the COXA 3 pin from my other board and it indeed shows shorted between pin 2 and 3.

author: sleepingAwake
author_rank: Contributor
timestamp: September 08, 2015, 04:05:03 pm
content: I currently have 4 TCON boards on my bench.2 Chinese boards, the original broken TCON and a used board I just received from a TV that would not have been in the affected serial number range.All but the used board I just received show a short on COXA. Bear in mind the used board didn't work either however. Just the first Chinese board showed a pic for a couple mins.I was thinking of flashing the firmware from the Chinese board to the oem I just received. Citing some sort of firmware mismatch. They are indeed different.I'm supposed to receive a TCON repair kit that may include COXA. It arrives later today.

author: freakaftr8
author_rank: Contributor
timestamp: September 08, 2015, 04:46:30 pm
content: Awesome. Anxiously awaiting the results. And if the COXA is substituted for a different part let us know what that is.

author: sleepingAwake
author_rank: Contributor
timestamp: September 08, 2015, 06:06:50 pm
content: Is there anyway to send output to the panel for testing purposes?I still don't think it's a bad panel. I went over the panel and panel connectors and could find no indication of damage. Not that you'd always see an issue. Especially with embedded chips in the ribbon cables.

author: freakaftr8
author_rank: Contributor
timestamp: September 08, 2015, 07:06:16 pm
content: Well I just got some interesting information. Some of these boards i have heard have a co5a in place of the coxa. In this transistor reference to a 5 amp 60 volt NPN style made by RoHm. Cross reference is 2SC5103 it is either a SOT428 or a SC63 package.The coxa mosfet is not cross referencable.I'm ordering some right now

author: freakaftr8
author_rank: Contributor
timestamp: September 08, 2015, 07:09:32 pm
content: I personally don't know how to output anything to the panel that's not going through its timing board first. However I'm pretty confident the panel's fine as sharp panels rarely fail in when they do usually if you leave one connector on while the other ribbons disconnected from the t-con to the panel you should see a picture on at least half the panel.Course that's just me personally finding panel faults that sharp usually seems to be the least amount of problems.

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 12:08:54 am
content: The repair kit did not arrive today. Shows out for delivery. I doubt the postman works until 9pm.

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 12:18:17 am
content: That sux. Well my board just arrived so let's do some testing. For the test that Coxa transistor before I even do anything else

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 12:27:09 am
content: Ok first glance the COXA transistor is no longer coxa it is now COPA and the reading between pin 2 and pin 3 is 523 ohms not 2 ohms like the bad board. Yet it is still a Chinese board. In a few minutes I'm going to test it in the TV

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 12:42:43 am
content: Ok. Board did not work. Now I'm getting 2.3 ohms between pin 2 and 3. This is extremely wierd. I did not hear anything pop or short out.

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 12:46:06 am
content: Wow.So what function does this component have?If there is excess current being drawn through it where does it go?

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 12:53:04 am
content: From what I can tell it apparently carries gamma processor ic voltages to the main processor. Probably could be the 1.0v Core voltage to the processor. There is another transistor showing a short too. The one to the left attached to the barrel capacitor. That is causing the capacitor to read dead short in an ohms test.

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 01:13:01 am
content: This only leads me to believe that the gamma ICs are bad on these boards right out of the box. I can't see a failed EEPROM taking out transistors. But that's just me and maybe somebody else can chime in

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 01:41:40 am
content: Not that this is going to help much but maybe. I recently scavenge parts out of a 55 inch Phillips TV that used a sharp panel. The t-con board is way different but the same in size in the pinouts to the main ribbon going to the mainboard are the same so I connected that tcon board to the main board and powered the TV up. I confirmed 12 volts 15 volts 3.3 volts and 1.2 volts working on that board so the main boards are obviously ok. I can't muster up the guts to try to connect it to the panel though because I'm sure it would damage the panel. But obviously clearly t-con board problem with these TVs not the panel

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 03:49:10 am
content: Things did not go well tonight.I decided to once again try the latest oem board I received.Hooked it up and was surprised to see I had my 12v, 3.3v , 5v and 1.2v in all the right places.I'm not sure if I only had one ribbon connector to the panel or both. I was fiddling with it more and checking for a picture and then I checked voltage again to find nothing but 12v into the dual mosfet AO4854.No output. Dammit.Checked COXA that was previously good and it's shorted. Double dammit.The only good news. I found COXA on Aliexpress.http://m.aliexpress.com/item/32378541068.html

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 04:37:55 am
content: Wow you found it that's amazing! Good work. I'm going to look through my stash for a cross reference.

author: Rasz
author_rank: Super Contributor
timestamp: September 09, 2015, 08:15:25 am
content: you do know the definition of insanity, right?replacing that transistor is pointless if you dont locate the cause of failing

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 02:30:10 pm
content: Your words could not be more true.My mission is to determine what is causing these parts to fail.Is it some transient event or excess current flow??? Could the panel itself be drawing to much current and blowing the components???Unfortunately it happens so fast it's hard to tell. No excess heat was observed during the time of failure yesterday.

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 03:13:29 pm
content: I'm on the same page as sleepingAwake. I'm not giving up.The transistor replacement alone is not a fix. I'm down to find the root cause and I believe it very well may be a failed or semi shorted gamma IC. This is the Maxim ic that the transistors are against. It may have a high current draw causing these sub par components to fail prematurely due to reverse bias.However last night I may be onto something despite that one transistor COXA being shorted which is a npn 60v, it is not receiving any voltage from the other bank of DC converter circuits. Which means the other two small transistors appear to be open. This means if they're open they are receiving 12 volts but not able to push anything out. I have one board that I'm messing with and I'm in attempt to replace those two open transistors with the equivalents. This will verify my findings if indeed the gamma processor is shorted it should take those transistors out right away. Boards are cheap and replacement kit are cheap as well so I figured it's a gamble but I'll give it a shot.

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 03:19:25 pm
content: A couple months ago I was researching problems with Sony t-con boards in the KDL-46XBR6 model. This is a known failure t-con and what gets taken out are the positive and negative MOSFET in the dc-dc converter circuits they fail from excessive heat. Replacing those transistors alone doesn't fix it but the diodes short as well and sometimes some other discrete components on those boards. Manufactured by AUO for Sony. A lot of people are not able to repair them but I managed to successfully Repair 3 of them. It's all trial and error.

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 04:53:52 pm
content: I don't know if it matters but I noticed the 60 inch version of this tv had a slightly different set of components. Most notably the transistor labeled coax seems to be replaced with a beefier component.It's probably not pertinent.http://www.ebay.com/ulk/itm/171909618790

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 05:16:12 pm
content: Thats a good eye! Yes in fact people try to swap the 6-0 inch with the 70 inch tcon to find that it does not work. The 60 inch must use a different voltage DC DC converter system. I saw rthat too earlier. Im not sure exactly what they are doing with the board revisions, but the 60 iinch boards are failing the same way even with the bigger compoonenets I believe.

author: freakaftr8
author_rank: Contributor
timestamp: September 09, 2015, 06:58:08 pm
content: Well I broke down and ordered a repair kit.. Lets see what happens, im still messing with my test board though.

author: sleepingAwake
author_rank: Contributor
timestamp: September 09, 2015, 07:16:32 pm
content: I'm still waiting on mine.I was shipped up to Vermont in error and now it's making its way back here.Good job USPS.

author: freakaftr8
author_rank: Contributor
timestamp: September 10, 2015, 02:43:50 pm
content: Yea I can imagine that is frustrating. I ordered my kit from Zemtronix out of Florida. Im in California, so this should be abbout 5 days.I have found an issue with some of those transistors. They are mainly NPN style and I replaced the COXA and the X7BV, as that one seems like its getting 12v on pin 1 and 3 but nothing on the gate pin. That is a problem. The XOYV shorts and shows up on the SMD capacitor on the right. This transistor I replaced with an equivlent, and I had no voltages try to come up like before, probably to to the wrons saturation voltages.The X7BV btw is not a transistor btw, its an N channel mosfet. Theres a problem here, something is disabling it.

author: sleepingAwake
author_rank: Contributor
timestamp: September 10, 2015, 03:55:22 pm
content: What about AO4854? It's a dual N channel mosfet.Before the failure the other night I had 12v,5v and 1.2v on different pins. Now just 12v source.Could that chip be blown as well?

author: freakaftr8
author_rank: Contributor
timestamp: September 10, 2015, 04:28:11 pm
content: Most likely but lets see what comes in the kit.. That should tell the tale of what goes south..

author: sleepingAwake
author_rank: Contributor
timestamp: September 10, 2015, 05:14:35 pm
content: Ill know later today. Shows delivered now.

author: That_boy_sammy
author_rank: Newbie
timestamp: September 10, 2015, 06:40:16 pm
content: Let me know how it goes. I called a repair shop and told them exactly what happened. They begged to differ saying the panel is causing the tcon to burn out. I cant seem to understand how an input only component(the panel) can revert power into destroying another component(tcon). Maybe it is possible. But im highly doubting that theory only because in my eyes i have only ever seen fuses blow before a matter when working on vehicles(thats what i do for a living).

author: freakaftr8
author_rank: Contributor
timestamp: September 10, 2015, 06:50:15 pm
content: Thats the easy answer for techs. The two tcons I picked up were bad out of the box. All low voltages DOA. This is without even connecting the tcon to the panel yet..Also note that some people replaced the tcon to find a perfect working picture for a few minutes to a whole day.. Panels that present a good image with no defects cannot destroy a tcon.. If the picture is good as far as the panel is concerened, all systems go.

author: sleepingAwake
author_rank: Contributor
timestamp: September 10, 2015, 07:01:14 pm
content: That was my thought process.I don't see how a panel with a good picture could blow out a TCON.I'm not sure what the amp draw is but I know the voltages are in the millivolt range.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 10, 2015, 08:56:05 pm
content: Quote from: sleepingAwake on September 10, 2015, 07:01:14 pmWith most LCD's usually that the case, if panel defective you have signs of it being defective and picture will have some type of defective and more likely spots. This model is the exception. I actually had one that had a bad panel with a perfect picture and did same thing, took same steps you did, thinking more likely defective TCON board that was used and tried another one, except brand new this time around and same results, took it out within minutes. It ended up being the panel, as TV was under warranty at the time and they sent someone out and replaced the panel and worked fine since before selling it.Doesn't mean your will be the same, could be very well something else.

author: sleepingAwake
author_rank: Contributor
timestamp: September 11, 2015, 01:47:02 am
content: Alright. Time to post the repair kit breakdown.The usual suspects are included.EEPROM - oddly enough blank. I was shocked. I suppose its up to the TCON's primary asic to program it upon first start.T1 - XOPA/17 meant to replace the component labeled XOSV/1L on my board.T2 - POY8A replaces X7KA/18 on my board.T3 - K72B8 replaces COXAAO4854 dual mosfet5a 32v fuse - I don't need.

author: freakaftr8
author_rank: Contributor
timestamp: September 11, 2015, 02:02:34 am
content: Nice! Let us know if it works when you install the kit!

author: sleepingAwake
author_rank: Contributor
timestamp: September 11, 2015, 04:13:26 am
content: Well I'm done.Installed the parts. Had good voltages.Hooked up the ribbon cables to the panel and within a min nothing.Never got a pic. Voltages gone.I am now fairly confident the panel is bad. Something about it is drawing to much current.

author: freakaftr8
author_rank: Contributor
timestamp: September 11, 2015, 04:17:26 am
content: Oh that sucks! Did you happen to catch what ic or transistor shorted?I'm still on with thinking that the Maxim gamma IC is bad. It doesn't get activery until current is pulled through it.Ill keep in touch with my kit repair.

author: sleepingAwake
author_rank: Contributor
timestamp: September 11, 2015, 04:24:02 am
content: COXA again. The dual mosfet seems dead as well. 12v in. Nothing out.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 11, 2015, 05:19:11 am
content: Being the COXA 16 transistor is shorted and dual mosfet seems dead very well could be the Gamma IC, which is a MAX9684 gamma voltage reference. The panel could have a short, one way to test is connect only one side with a good TCON. You may need a couple as you have test each side and may short the board if you get the shorted side of the panel connected first, so get 2 good TCON broads, First plug in one half of the panel, when you get a new TCON, if it stay on, then unplug and plug in the other cable, if it shorts, then the panel has a short, or excessive current draw and no point in continuing further.

author: Rasz
author_rank: Super Contributor
timestamp: September 11, 2015, 07:38:56 am
content: power tcon from external source with current limit, no point burning parts all the time

author: freakaftr8
author_rank: Contributor
timestamp: September 11, 2015, 04:19:04 pm
content: Am I correct on my approach of connecting the t-con board to the main board to supply power but not connecting the ribbon cables from the panel to the T CON for testing purposes to make sure that all low voltages are present. I've done this many times before with success with other models making sure that the board is OK. But does this board overload somehow without the panel connected kinda like going into overcurrent because it cannot output overloading from circuit in and blowing certain components on the board?

author: sleepingAwake
author_rank: Contributor
timestamp: September 11, 2015, 04:35:34 pm
content: No it was fine until I connected the ribbon cables to the panel.The advice from Rasz is the best way.Power the TCON with a current limited power supply. Next on my list of troubleshooting devices for the bench.

author: freakaftr8
author_rank: Contributor
timestamp: September 11, 2015, 05:54:40 pm
content: I agree, he's right.. Im assuming bench testing would involve a current limited device or a fuse with a very light rating with a power adapter that produces 12vDC injected into the main fuse of the tcon.

author: That_boy_sammy
author_rank: Newbie
timestamp: September 12, 2015, 03:55:24 am
content: Jumped ship boys. I found a deal at wal bogs, $699 for a 65". My tcon is in the freezer right now. Thatll be my last attempt at this. Two things can happen, a catastrophe or...a miracle. Lol im dead serious its a hail mary

author: freakaftr8
author_rank: Contributor
timestamp: September 12, 2015, 08:49:08 am
content: Ok people I have found the problem. I managed to Repair one of the T CON boards with replacing the XOSV with aQF which is a RTR020N05 2a 45v n channel SOT-23 style mosfet. That apparently was the only problem on this board. The EEPROM is fine and so is the 4 channel MOSFET DC converter. Powered up the TV and had a V logo and then it faded away. But it turns out to be is the right side of the screen is shorted. Bad panel. If I left it plugged in it will for sure destroy the t-con board again. Obviously a very ill designed Sharp LCD panel. One of the side tab drivers are bad on the panel. There is a direct short.

author: That_boy_sammy
author_rank: Newbie
timestamp: September 12, 2015, 01:45:55 pm
content: Hmm. What about the chip set thats mounted to the bottom of the panel? Ill have to take a look at that later for any obstructions.

author: sleepingAwake
author_rank: Contributor
timestamp: September 12, 2015, 05:14:17 pm
content: Nice find freak.I believe mine is shorted in the same manner.I wonder if it's the chip on film in the ribbon cables.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 12:22:39 am
content: Yep. Unfortunately it is the chip on film on the TFP on the right side right underneath the bottom center if I disconnect the right side TFP drivers from the bottom of the panel ribbon cable on the bottom right of the panel the picture Works with both sides connected on the tcon except the right side is a lot darker in very very slow to refresh motion blur if you will just like one of the Samsung panel goes bad and you have to press on the frame to get it back. These sharp panels are not forgiving at all as soon as I wiggle the driver ic the screen tries to come back but it does not look ok and I try to shim it does not work. Settle with the driver carrier too much is the screen will completely blanked out annual hear tcon bored making a slight tick tick tick noise as the panel is trying to short out the tcon again

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 01:23:21 am
content: Sadly for such a decent television this model is inadvertently made to fail. The chip on film driver that is on the sides of the panel are not pressed up against any metallic surface for active cooling.Crap design. Now I know what vizio meant about chipset failure. It's the panel causing damage to the tcon.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 02:55:24 am
content: Guys I'm on does something stay tuned this is going to blow your mind

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 02:59:51 am
content: As low as it doesn't blow my TCON.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 13, 2015, 03:03:25 am
content: 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

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 03:18:31 am
content: 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

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 03:20:01 am
content: 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

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 03:28:39 am
content: 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

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 13, 2015, 04:38:44 am
content: Quote from: freakaftr8 on September 13, 2015, 03:28:39 amAt least you got it to the point of being useable, rather then end up in the landfill and parted out. Still great progress .

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 05:15:54 am
content: 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???

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 05:37:10 am
content: 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

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 04:34:21 pm
content: 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?

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 04:44:10 pm
content: 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.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 04:53:19 pm
content: 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 donehttp://www.badcaps.net/forum/showthread.php?t=48477&page=3

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 05:43:52 pm
content: Wow. Okay well after I repair yet another TCON I'll give it a shot.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 07:06:14 pm
content: 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

author: That_boy_sammy
author_rank: Newbie
timestamp: September 13, 2015, 07:12:15 pm
content: So once that tab driver is removed another cannot be replaced with it?

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 07:14:07 pm
content: No. These drivers are bonded to the panel at the factory and are not technically made to be removed.

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 07:26:01 pm
content: 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.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 08:13:36 pm
content: 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

author: sleepingAwake
author_rank: Contributor
timestamp: September 13, 2015, 08:17:58 pm
content: 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.

author: freakaftr8
author_rank: Contributor
timestamp: September 13, 2015, 08:56:21 pm
content: 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

author: sleepingAwake
author_rank: Contributor
timestamp: September 14, 2015, 01:32:14 am
content: My dc-do converter is blown. All of them. LolI guess I will have to wait. Digikeys minimum is 3000

author: freakaftr8
author_rank: Contributor
timestamp: September 14, 2015, 02:39:38 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: September 14, 2015, 03:13:00 am
content: 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 cheepI 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.

author: freakaftr8
author_rank: Contributor
timestamp: September 14, 2015, 02:32:28 pm
content: 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..

author: sleepingAwake
author_rank: Contributor
timestamp: September 14, 2015, 08:36:02 pm
content: Thanks man. You rock.I need to get a current limiting psu so I don't blown the thing up when I connect it.

author: freakaftr8
author_rank: Contributor
timestamp: September 22, 2015, 04:04:21 am
content: 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.

author: sleepingAwake
author_rank: Contributor
timestamp: September 22, 2015, 04:09:52 am
content: Nah not yet.Frankly I'm scared I'll blow the thing up faster than I can unplug it.

author: sleepingAwake
author_rank: Contributor
timestamp: September 23, 2015, 12:46:10 am
content: Got the board today freak.Hooked it up and just connected the right side ribbon cable.Wife said it had some horizontal lines and vertical lines on both sides of the TV. Mostly the right side.Tcon blew. I had it connected for 2 seconds. Literally 2 seconds.So yeah. Big day.

author: freakaftr8
author_rank: Contributor
timestamp: September 23, 2015, 07:20:23 pm
content: Dammit. That sucks! Your right side is for sure bad. If you feel up to it order that transistor I replaced. Bet that's all that blew. Then connect only the left side leaving the right side side ribbons disconnected from the bottom boards. Bet it stays on.

author: sleepingAwake
author_rank: Contributor
timestamp: September 23, 2015, 09:00:02 pm
content: I got some transistors and some dc to dc converters coming from China.I'll let you know what happens when they show up.

author: sleepingAwake
author_rank: Contributor
timestamp: September 26, 2015, 08:11:22 pm
content: Ok so here's the deal.I repaired all the tconsTested each one for proper voltage.When I connect the ribbon cable going to the right side of the TV I get some white flashes and horizontal lines.When I connect the ribbon cable going to the left side nothing.If I disconnect the ribbon cable on the left side that joins the two horizontal gate driver panels together the left side of the screen goes white and stays white even without a tcon connected.I'm not sure what my next move should be.Do I remove the left or right side gate drivers???Read carefully and give me an opinion please.

author: sleepingAwake
author_rank: Contributor
timestamp: September 27, 2015, 02:22:27 am
content: Never mind.It had at least one blown vertical gate driver and probably some horizontal ones as well.Oh well.I'm going to use it as a desk light and hang it above my bench. No joke.

author: freakaftr8
author_rank: Contributor
timestamp: September 27, 2015, 05:36:27 am
content: Oh man that does suck. I'm sorry..we gave it a valiant effort thou. When a vertical gate driver fails it's game over.Oh well. Like the idea of a desk light. I did this with a 39 inch samsung led that had a cracked screen. Works well.. at least you'll get some use out of the damn thing since it's been so stubborn. Give it hell lol