Wednesday, April 27, 2016

Panasonic TC-P55ST30 7 blinks help and repair SC TNPA5351 and buffers

Just finished uploading a video on troubleshooting Panasonic TC-P55ST30 plasma TV that doesn't want to start and blinking 7 times on the front LED.

It was actually broken up in 3 parts you can find on YouTube:

Troubleshooting Panasonic  TC-P55ST30 part 1:
 

Troubleshooting Panasonic  TC-P55ST30 part 2:

Troubleshooting Panasonic  TC-P55ST30 part 3:

Those are not a complete DIY videos and do not show you how to actually do the replacement and repair parts; they are focused more on diagnosing the problem.

We haven't activated the corresponding repair services and repair kits at the site yet, but chances are by the time you hit this posting we already would have had it done. (is that a proper tense?)

Those should help you find them:

http://www.coppelltvrepair.com/search?q=TC-P55ST30

http://www.coppelltvrepair.com/search?q=TNPA5351

Now, I would like to summarize the videos that way:

1) To troubleshoot a TV you need a multimeter. It doesn't have to be a nice Fluke, a generic $30 device would do 99% of the time.

It is worth spending some time watching YouTube videos on how to measure voltage and resistance with the device.
For sake of finding shorts and generally troubleshooting resistance (or continuity, which is the physically and mathematically opposite of resistance) is usually measured using the DIODE symbol on the device's dial for reasons you can find explained elsewhere.

2) You need to take off the back cover of the TV. Some TVs allow it to be taken while the unit is on its feet/pedestal, others require that the pedestal is taken out and the unit is laid flat.
It is quite OK to lay a plasma TV flat on a table.

3) If you see lots of dust in a TV (or any other device) take it out and suck it or blow it out of it. Doing that earlier is better than doing it later when you've picked and / or inhaled large portions of it.
Do as we say , not as we do in this video :-)

4) Most commonly failing power components in plasma TVs are transistors and diodes.
Transistors have 3 electrically different legs and diodes have 2 even though it is possible for a particular component that is a diode to have 3 legs and look like a transistor; this would be when inside there are 2 diodes with one common electrode or simply two of the legs would be the same electrode.
On boards didodes are often marked with prefix D followed by a number while transistors are often marked with prefix Q followed by a number. D101 is a diode, Q101 is a transistor.

5) You check for defective diodes and transistors by testing each possible combination of electrodes for low resistance near to 0. A true failure would have the same low resistance in both direction, e.g. by swapping the places of the meter's probes you should get the same low reading.
Low reading in only ONE direction is usually indication for a GOOD device.

The separation between diodes and transistors is only important for the sake of knowing that in some cases you will find "shorted" electrodes, that are such by design - namely in diodes made with 3 electrodes.

6) Two things to watch for when looking for shorted components:

First, often times components are in parallel; one shorted component may make others appear shorted as well. Which means the first component you find shorted is not necessarily the actually bad one.

And second, sometimes low resistance can be found between two electrodes of a power component by design; this is fairly common with transistors in particular and easily recognizable once you establish the pattern, which is that such resistances have "rounded" values of say 15 or 20 ohm, which are hard to achieve my a failure (not impossible though!) and, most importantly, can be easily tracked to a resistor located nearby.

7) Not just SMD components fail. Check the ones on the heat sinks as well.

In addition, not only components included in repair kits sold by SJ and others fail. Many times companies sell you repair kits that were not even based on actual experience repairing boards.
Do not trust that if you buy a repair kit from SJ or even CTVR it will have all the parts you need!
But naturally I think it stands to reason to trust companies who offer repair services in addition to repair kits.


8) Transistors are sometimes organized in groups of 2, 3 or more working in parallel (one particular electrode labeled G leg is usually connected to the other G-s via small resistors while the other electrodes are directly electrically connected to the same electrodes from the other components in the group).
Determining which one of those has failed is subject of another article for sake of space, but it is a good idea to replace all of them when one fails.
It is not a must in most cases we've seen, but in some cases it is.
For Panasonic TC-P55ST30 it doesn't seem to be, but we still do it.

9) We've seen different failures on different boards; the video identifies the components we've seen fail.

You can get a repair kit from us or send the board for repair if you wish.

10) When the sustain board fails a buffer board may or may not fail along with it.

When it fails it is usually, but not necessarily the top (SU) buffer board.

The videos show you how to test for failure (short) on a buffer board and how to identify the faulty IC.

The method shown is 99% reliable meaning it leaves about 1% of the times when the board would be bad, but the shown check may not reveal it. The devil is in the details, right?

You can buy the ICs for the buffer board repair or send them to us to have them repaired and tested.

Hope this helps!

Vizio M470NV main board 3647-0302-0150 repair service available

I am happy to announce Coppell TV Repair LLC now offers repair service for the main board 3647-0302-0150 found in Vizio M470NV.

We also offer a board sale with trade-in option, but knowing how people tend to either not return old duds or return ones that have been badly tampered or - let's be honest - in some cases return duds that are perfectly intact and we still fail to repair - I wouldn't be surprised if we run out of working boards as well.

http://www.coppelltvrepair.com/p/1354/repair-service-for-3647-0302-0150-main-board-for-vizio-m470nv-smart-led-tv-totally-dead-blinking-endlessly-or-otherwise-failing-to-start

http://www.coppelltvrepair.com/p/1354/repair-service-for-3647-0302-0150-main-board-for-vizio-m470nv-smart-led-tv-totally-dead-blinking-endlessly-or-otherwise-failing-to-start


Just for the record, in order for us to announce a repair service it means we've been successful repairing a few and have typically seen at least two different issues; of course we are fully aware there's probably a whole lot more we haven't seen yet.

That is one of the reasons we do not promise success for any of our repairs (although for some we've done so many and have so many duds at the end of their life cycle we actually can promise a working board back, even if it means repairing and returning one of those old duds; then again, at this point of the life cycle people usually do not rely to repairs, but just buy cheap working boards off eBay..which is not always wise).

It is also one of the reasons why we do not charge upfront for any repair at www.coppelltvrepair.com .

A failed Vizio M470NV can cause loss of HDMI ports, loss of audio or video or TV that is totally dead, stuck to orange front LED or forever blinking and possibly others.

We also offer the flash memory IC (often referred to as EEPROM) for this and other Vizio models.

Friday, April 22, 2016

Vizio XVT553SV totally dead or HDMI ports not working


Lately we've been doing a lot of Vizio power supply and main board repairs.

As you may know by now the Vizio  TV brand is almost exclusively handled by Sharp and a lot of problems are common for their TVs since they follow the same design and production pattern and transfer the same design and production defects among different models.

One common issue we see is TVs failing to power or starting up with some issues such as HDMI ports not working or the audio output being either too quiet or missing at all.

We started offering the flash memory ICs for some Vizio models as well as repair services for the boards:


http://www.coppelltvrepair.com/p/1355/repair-service-for-3655-0122-0150-main-board-for-vizio-xvt553sv-smart-led-tv-totally-dead-blinking-endlessly-or-otherwise-failing-to-start

Friday, October 9, 2015

Why Y-Main and buffer boards should NOT always be replaced together

In a daily language "experts" are usually people who do something more intense and, preferably, do it for living as opposed to as a hobby or on the side.

"Specialist" is a bit better word in that context and frankly I do not want to go down to semantics as much as I'd like to separate people who develop extensive expertise in a particular area versus all others.

Without being top notch I consider myself an expert in plasma , LCD and LED TV repair due to the fact that i do it a lot and , if anything, my experience and guessing would likely be better than that of an average customer even if I happen not to be the brightest of service engineers out there.

All that said, I am often reminded how bad an expert advice can be.

A quick illustration is a blog article I came upon today, which explains why is it better to replace a plasma sustain board along with buffer boards.

The contents of the article may change after my post, so I'll copy a snippet here without author's permission. I looked for place to comment under the article to tell them what I am telling you, but there was no option to leave comments , so I am instead doing it here.

"This is actually a fairly common problem amongst Plasma TV's. The Y-Sustain Board often times go kaput and you run into the problem of "no picture but still having sound". Everything else seems to work like volume control, changing the channels, and even changing the input from one to next. No problem, you think to yourself. Just replace the Y-Sustain Board and you should be good to go, right? Hold on there, cowboy. Before you go and do that, understand for a moment that Plasma TV's, unlike LCD TV's and LED TV's, is a different type of TV technology and thus, the way it operates is also different. If and when "a part goes out," it works in a domino effect. In other words, when one board goes out, it often times takes out another board with it. 

In a Samsung HPT5054, it uses this Y-Sustain and Buffer Board set: LJ92-01490A & LJ92-01491A & LJ92-1492A. Now, inside your TV, the direction of electrical current travels from left to right and when this set is inside your TV, from where you stand with the base of the "TV Stand opening" facing towards you, it would be from the "bottom up" that the electrical current travels. And in this particular TV model, usually the "short" comes from the lower buffer board (LJ92-01492A) that ends up blowing out the Y-Sustain Board. In other words, when the lower buffer board goes bad, it usually takes out the Y-Sustain Board along with it. And before you go jumping the gun and concluding that maybe it's prudent to replace the Y-Sustain Board and just the lower buffer board without also replacing the upper buffer board as well, this is actually not a good idea. Why? Because if the lower buffer board goes bad and takes out the Y-Sustain Board along with it, it is just a matter of time before the upper board goes bad. And then you run into the same problem except this time, it will be the upper buffer board blowing out the Y-Sustain Board. In this case, it's a lot like how your mechanic recommends that when you replace your tires or shocks and/or strut assemblies, that they should be replaced in pairs, rather than individually because of the same rationale: when one goes bad, it's highly probable that the other one is on its way out even though it appears to the naked eye that nothing seems to be wrong with it. And if nothing else, replacing the Y-Sustain Board together with the Buffer Boards will sufficiently eliminate the possibility that the short was coming from the upper buffer board thus minimizing the chances that you would end up blowing out one of the two working boards that you just bought. Ultimately, it saves you time and money to replace them together as a set rather than replacing two of the three only to have one of the old boards blow out on you and taking out one of the two perfectly good board you had just bought a week ago. And these Y-Sustain Boards don't come cheap nor are they easy to find."


While there is definitely some truth to the above, there is also a fair amount of errors and misconception resulting, at the end, in an incomplete at best, and more rightfully misleading conclusion and recommendations.

Here's why:

1) The article builds a case based on one example and fails to review everyday practice for other possibilities.

Samsung HP-T5054 does have a tendency of blowing a buffer board and taking down the Y-Main board as a result, that is correct.

However I can list tens of TVs - practically all Hitachi models I know and most of the LG based ones as well - where this is NOT the case.

HP PL5060N is a 50'' plasma from about the same time when Samsung HP-T5054 was made. It tends to blow the YSUS and the ZSUS boards however rarely ever the buffer boards are affected.
And the buffer boards are practically never the source of the YSUS failure.

So the case of having to replace all 3 boards together goes down the drain from the sake of cost efficiency and even pure technical requirements.

In case of the Hitachi plasma TVs from the same time frame, buffer boards tend to fail a lot - kind of like with Samsung - but they rarely ever affect the sustain board. 1 in 100 or something to that extent.

We highly recommend that people do not replace the sustain board simply because it is not needed.

In short: Y-Main and buffer boards SHOULD NOT always be replaced together.

2) The article talks about the lower buffer board failing on HP-T5054 and specifies it as LJ92-01492A.

That is flat our wrong.

We have about 200 lower buffers L92-01492A available here, result of customers replacing the set of buffers with new ones.

The lower buffer rarely ever fails!

What is the conclusion?

Well, whoever wrote that article is not really a TV service technician. No offense meant.

For my two cents whoever composed the article is fairly intelligent as it is well written (well interpreted from other sources is my exact opinion) and it improvises a bit over the original.

But it lacks what it needs most, which is first hand experience and proper application of logic specific to the issue.

I do not mean to offend the author or the other company in any way.

I want to make a point that one should not believe everything they get from what can be perceived as an expert in a certain area.

That includes our own advices, of course :-)

Take any way you want.

Saturday, October 3, 2015

Issue with customer disputing repair service after granting no warranty repair

Below is an email correspondence I will post without edits other than removing emails for the sake of keeping privacy.

Reading it may not be very easy because of the way Outlook organizes email history, but I want to post it without changes and quickly.

To read it properly start from the bottom and work your way up to the top. That is how email history goes.


Most readers will not find it of interest, but hopefully PayPal will.




Ø Your terms and conditions imply that you do not want ME to fix the board, not others. 

I disagree with that.

And will quote you the requirements once again:

We ask that the board arrives here in good physical condition and without traces of tampering. If someone (other than us, that is) has already attempted to service the board…”

Not only the statement does not talk about you, the customer, in fact it explicitly states someone (other than us, of course).

You may interpret the language any way you want, but that is the reason agreements are read not for what they imply, but for what they say.

And ours most definitely does not say anything about YOU not having worked on the board.

Ø What the prior technician did, and whether or not that constitutes “tampering” with it, is beyond my lay expertise. 

There is nothing wrong with that.

But it is within our expertise, which is the reason we contact you BEFORE we do anything else.


Ø If I have my oil changed at Jiffy Lube, do I need to inform the Toyota dealership that I might have tampered with my car, thus affecting its warranty?

You may want to check your agreement with Toyota about that – I am definitely not informed enough as to speak on their behalf.

But I am quite sure that there are places and services that will void original Toyota warranty.

Again it is up to you to know what they are and I am sure they are in the car’s service terms and conditions.


Ø With tax, I got charged over $100.  (No delivery charge cause he was local.)  When I called back to complain, his phone no longer worked.

Even if he would have answered the phone, I don’t think I would have paid him again to fix it, especially since there’s never any warranty on electronics.  I doubt he would have given me my money back.  AFTER I paid upfront, I noticed he was a “last word” argumentative type of technician.  Kinda arrogant too. 

Sorry to hear that, but I do not see how it is related to us.
We can’t be responsible for what others do and how they do it.

We may sympathize with people, but that doesn’t make our job any easier – it is still harder as we still have to go over what others have done before us.

Hence the requirements in the listing.


Ø Ultimately, I chose you because you claim no up-front fees BEFORE you TRY to fix anything.

Well I must say you are receiving a full benefit from doing that and frankly so are we.

We can’t usually fix a tampered board at the same cost at which we’d fix a factory one with original failure and we know from experience it’s much harder to convince someone in that AFTER you’ve already got paid….hence the no upfront payment policy.

We also wish people could help avoid situations by telling when they board was worked on previously, but as you can see they can’t always do that.

Part of business and we have to live with it as much as those customers have to.

> If need be, and so that I can avoid these types of disputes in the future, I’ll consider buying a whole new board or TV. 

Well I can tell you that if buying a brand new board was an option we would not be offering a repair service for it.

It simply isn’t J

Brand new TV you can always consider buying and we are not at all trying to convince you that you should not.

For the record we believe it has its pros and cons, but ultimately it depends on the personal decision and ability to stay with it.

Ø At least when something’s bought off the shelf, the store has to go out of business at or before the warranty expires in order to break all ties to what it has sold, all while continuing to purport that the customer’s always right since cash is King and therefore boss.

This is a personal opinion that does not affect us as a business entity and as such I can not give you an official position on it, but on a personal note I’ll point out that a) standard warranty for TVs these days is 12 months and the board in reference is 7 years old - you do the math; and b) not everyone is of the opinion that cash is King and customer is always right; some are of the opinion that presenting rules upfront and managing to contain business within those previously announced rules is more important than making more cash.

Best regards,

Bobby Kolev
Manager
Coppell TV Repair LLC
 
From: Hans Croteau
Sent: Tuesday, August 11, 2015 2:05 PM
To: Bobby Kolev
Subject: Re: Update on case CTSR1508044024 from Coppell TV Repair LLC

Bobby,

I’m not the one who fixed the board before I sent it to you.  When it broke again, I didn’t ask the same person to fix it precisely because of my concern that I might have to fix my TV every two months.  Your terms and conditions imply that you do not want ME to fix the board, not others.  What the prior technician did, and whether or not that constitutes “tampering” with it, is beyond my lay expertise.  If I have my oil changed at Jiffy Lube, do I need to inform the Toyota dealership that I might have tampered with my car, thus affecting its warranty?  With tax, I got charged over $100.  (No delivery charge cause he was local.)  When I called back to complain, his phone no longer worked.

Even if he would have answered the phone, I don’t think I would have paid him again to fix it, especially since there’s never any warranty on electronics.  I doubt he would have given me my money back.  AFTER I paid upfront, I noticed he was a “last word” argumentative type of technician.  Kinda arrogant too.  Ultimately, I chose you because you claim no up-front fees BEFORE you TRY to fix anything.  If need be, and so that I can avoid these types of disputes in the future, I’ll consider buying a whole new board or TV.  At least when something’s bought off the shelf, the store has to go out of business at or before the warranty expires in order to break all ties to what it has sold, all while continuing to purport that the customer’s always right since cash is King and therefore boss.

Hans

From: Bobby Kolev
Sent: Monday, August 10, 2015 7:15 PM
To: Hans Croteau
Subject: RE: Update on case CTSR1508044024 from Coppell TV Repair LLC

Ø I simply sent you the board after it went out again, and after following your directions. 

Good. Directions is not the only thing we give though.
There are also conditions – much like in any other deal.
See listing or see below for a partial quote.
Ø It isn’t the first time this board gets fixed.  (In fact, I think there were at least two prior fixes, but the TV worked fine for at least a couple months.  I also bought the TV used, not new.) 

That is exactly what the below quoted condition addresses.

Ø I did notice a zap on the green round capacitor when I plugged it in according to your instructions on the internet. 

No big problems with that.

Ø Your internet site is evidence that you instruct your customers to determine if the failure is caused by the Y-Main boards, as you state this is a common problem with these 50 inchers. 

A very good evidence for a very good advice.

Nothing to do with the tampered board, though. I am sure we do not instruct customers to replace components, in fact I am sure we request the opposite.
Ø I fail to see how I could be in clear violation of your service terms.

Well here it is, straight from the listing:

Board requirements
We ask that the board arrives here in good physical condition and without traces of tampering. If someone (other than us, that is) has already attempted to service the board then please contact us with a description/pictures and do not directly place an order. We reserve the right to refuse service to boards that have signs of repair attempts.”

Ø As I recall, you advertised some $75 to $80 to try to fix the board. 
That is a good, but not excellent recollection.
It would have been excellent if you had read the listing, including the above quoted section.
Without it you are just remembering the part that you’re interested in, but without the other half we’re not interested in the repair.

Ø I don’t recall if there was an extra charge or not for re-delivery. 
Not sure what are you referring to, but to the best of my own knowledge there is nothing about re-delivery either.

I am not even sure what a “re-delivery” is.

Ø So in essence, you’re asking me for $110 to repair and deliver it back to me, which is $25 to $30 dollars more.

No, in essence we say that if we proceed with the repair and if we are successful then you will end up paying more.

Assuming we will be successful equalizes my statement with yours.
Ø As I recall, you sell $100 boards with a DUD exchange of $50.  Whether you want to try to fix it, or whether you just prefer to keep it as the DUD and sell me an already repaired $100 board with a $10 delivery cost doesn’t really matter to me. 

I believe you have not read our sale/trade-in offer in its full either.

Please do so.

You will find that it contains the same clause which prevents customers from receiving full credit for returning boards that have been tampered with.

It’s there for a reason and that reason is not to make us money. We are VERY aware people do not like price changes.

I wish people were equally aware it doesn’t cost the same to repair an original board with a failure and one that has been tampered with.

If not that I wish people were at least aware of our requirements that are there in plain English.

Ø I’m willing to pay you the $110 to get a working board delivered to my home, irrespective of how that gets done.
All you had to say was “I will go with option 2.”
Will do.

Best regards,

Bobby Kolev
Manager
Coppell TV Repair LLC
 
From: Hans Croteau
Sent: Monday, August 10, 2015 8:30 PM
To: CoppellTVRepair
Subject: Re: Update on case CTSR1508044024 from Coppell TV Repair LLC

Dear Coppell TV,

I simply sent you the board after it went out again, and after following your directions.  It isn’t the first time this board gets fixed.  (In fact, I think there were at least two prior fixes, but the TV worked fine for at least a couple months.  I also bought the TV used, not new.)  I did notice a zap on the green round capacitor when I plugged it in according to your instructions on the internet.  Your internet site is evidence that you instruct your customers to determine if the failure is caused by the Y-Main boards, as you state this is a common problem with these 50 inchers.  I fail to see how I could be in clear violation of your service terms.

As I recall, you advertised some $75 to $80 to try to fix the board.  I don’t recall if there was an extra charge or not for re-delivery.  So in essence, you’re asking me for $110 to repair and deliver it back to me, which is $25 to $30 dollars more.  As I recall, you sell $100 boards with a DUD exchange of $50.  Whether you want to try to fix it, or whether you just prefer to keep it as the DUD and sell me an already repaired $100 board with a $10 delivery cost doesn’t really matter to me.  I’m willing to pay you the $110 to get a working board delivered to my home, irrespective of how that gets done.

Hans S. Croteau
From: Coppell TV Repair LLC
Sent: Monday, August 10, 2015 10:06 AM
To: Hans Croteau 
Subject: Update on case CTSR1508044024 from Coppell TV Repair LLC

Dear Hans Croteau,
Just finished inspecting the board you sent us.

It has clear signs of a previous repair service attempt, which is in direct violation of our requirement in the listing.

We offer flat rate repair services addressing a number of problems we have already seen and developed know-how for addressing, allowing small room for occasional complications which tend to get less and less over time.

Human interventions cause complications and delays in 8 out of 10 times...sure enough we've seen enough of those to have a statistic about it too.

In those 8 out of 10 times the project ends up costing us money rather than generating profit.

Hence the condition in the listing.

Based on that and the condition of your board here are the options we offer:

1) You can get the board back for the sole cost of the return shipping charges ($14)

2) If we proceed with the repair and the board is bad and we succeed repairing it you will pay $110.00 including return S&H

3) If we proceed with the repair and we fail to fix the board you will have to pay $25 plus return S&H

Additional notes:
none

Let us know what would you like to do!


Friday, September 18, 2015

272217100569 / 2300KEG031A-F transformer burning, raising children and economic riddles

I'll put it right there with the clear understanding that many may call it selfish, wrong, or, likely in the case of certain family members who are not my husband, just typical:

Customers sometimes want too much while offering too little.

There, you can quote me on that.

I'll present my argument in this form of true email communication from earlier today:

Question:

"REPAIR SERVICE for power supply board 272217100569 / 2300KEG031A-F

Question, I had a tv that was doing this that you mention------>>>>>TV powers on, possibly with an image for a second, then the display gets dark, but the TV remains on.

Ok so I replaced the likely capacitors that have degraded over time, and I also re-soldered a lot of  the power components including around the transformer T701 and I have a fully functional working TV with no more going dark.  

My problem is there is a slight smell coming from that Transformer and it is hot.  What is the root cause of that transformer being so hot and eventually causing the burn out that you mention "burning around the transformer T701 at the top left side of the board"?  Did you guys ever figure that out? Is that transformer undersized? How do you all implement a permanent fix?   Any help would  be greatly appreciated. "

Answer:
"I will answer your questions and then ask one in return.

Transformer may be getting hot for different reasons. 

  • The most common one is an arcing between the copper wire and the leg it is soldered to which is a result of a degradation of the solder that joins them.
  • Yes we did figure that out.
  • No the transformer is not undersized.
  • A permanent fix to this problem is a solid joint between the copper wire and the copper track under the board.

Now for my question: do you happen to know how to transform appreciation to food?
Because neither of my kids wants appreciation for dinner.
I tried."

Your 2c?

P.S. A day after posting this we got the following question on eBay for one of our repair services:

"I'm sure you won't tell me how to fix my own main board, would you?"
 

Thursday, July 2, 2015

Toshiba 42XV540U backlight and no image on screen repair

It's been a while since I blogged component level repair, so here's something.

A customer brought a Toshiba 42XV540U LCD TV after we've serviced the power supply PE0580A for him.

He said the TV started responding and clicking after our repair, but the display remained dark.

We agreed on returning the money for the board repair and taking the TV instead as he said he didn't want to invest more time with it.

So summarize:
TV model: Toshiba 42XV540U

Failure symptoms: TV responds to power on command, fans start turning and back light comes on (we could see from the back of the TV and a glow could be seen from the front, but only in a dark room).
We could not make the TV output sound by blindly trying to change inputs; if you know how to do it perhaps you can do it , thus eliminating the main board as a top suspect.

Solution:  The TV was responsive to on and off commands, which suggests the main board was good.
(failed main boards usually fail to do one or both of those operations). Plus backlight was coming up, which means the main board's processor was up and running to the point of activating the backlight.
On the other hand we couldn't get sound out of it.
We checked the voltage going to the T-CON board and it was there - 12V DC.

So the options were the main board (less likely), the T-CON or the video accelerator PE0578 (about equally likely) or the display itself (unlikely, it rarely ever fails to all dark screen).

Luckily it turned out we had eBay listings for both the T-CON and the accelerator board.

Testing with them it turned out the problem was in the accelerator board PE0578.

Knowing that we've put the bad and the good one side by side and started hunting:



Found the problem in the voltage stabilizer from 12V to 3.3V.
As you can see there was a significantly lower resistance there and, more importantly, it was the same in both directions on the bad board:


On the good board it was a good diode read - 0.5 - 0.6 kOhm in one direction and infinite or very high in the other:

(The measurement can be made on several points and there are several components there that could be causing it; there were a few inductors we removed in order to eliminate the circuits after that as well as a few diodes that were in parallel and could have been causing the shortage).

The only passive component we found to have been bad was diode  D592 on the back of the board. It was fairly well shorted, having about 4-5 Ohm in both directions:



Used generic diode for replacement, such as the ones used in our repair kits for BN44-00161A power supply. Almost any diode will likely do, including even zener diodes (assuming it's properly soldered in regards to its polarity, of course).

Long story short, we traced it down to the actual DC converter/stabilizer IC (AOZ1017AI).

But since we didn't have a replacement handy and our US vendor didn't have it either (had to ether use another US vendor or our Asian vendor), we took matter in our hands and just hacked a stabilizer of our own:



The solution worked out well and the TV is presently operational.

While I don't give out everything I hope this helps someone save a buck or two :-)

Good luck!