Tuesday, April 22, 2014

Philips 42PFP5332D/37 dead, power clicking on and off

Today I've seen something that I do not think I've seen once in the past 3-4 years so I decided to show it.

A power supply board SAMSUNG PS-426-PH / LJ44-00143A came in today, from a PHILIPS 42PFP5332D/37 plasma TV.

The customer had actually sent it by mistake because we do have a listing for another power supply board used in a different chassis version of the same TV model:

http://www.coppelltvrepair.com/p/217/magnavox-42mf237s37-philips-42pfp5332d37-power-supply-board-repair-service

Well the board in the above listing is NOT PS-426-PH / LJ44-00143A , but the customer went by the model number and we ended up with a board we have not worked on before.

Here is your Samsung  PS-426-PH / LJ44-00143A for Philips 42PFP5332D/37:
 (the picture is of the actual customer's board; they had their contact info written on it so I had to smudge it a little with Gimp; I am sure there are better ways to do it, but I just smudged it).

It had a blown 4A fuse (F8005 located between the two large capacitors in the middle of the board) and a quick test showed barely a few ohms resistance from the inside part of the fuse to ground - a pretty darn good reason for blowing if you ask me.

Nothing unusual so far, right?

Well, I tested the power FETs and they were good.

I tested the power driver ICs for the Va/Vs transformers (they are separate on that board) and they were also good - nothing remotely close to short.

There aren't many other power components on the other side of that fuse, honest.

After 15 minutes of finding nothing I started desoldering the primary windings connections on the transformers....still nothing.

The only really LARGE and powerful component I have not checked was the filter capacitor
C8054 (220uF/450V) , one of the two large capacitors around F8005 on the picture.


I did not check it for two reasons:

First, it didn't look bulged, worn out or anything unusual, at least from the top; it's a little tight there so it was hard to see it all, but again nothing significant.

Second, I do not remember having ever seen a large capacitor like that short out; I've seen many dry and get infinite ESR, but I haven't seen a shorted one.

Well lo and behold:

A steady low resistance on a capacitor this size and voltage was something I saw for first time in long enough to feel like first time ever.

That turned out to be what killed the fuse.

Just for the record, C8023 was visually swollen and had to be replaced and the Vs output filter capacitor was also bad although still functional. I have not taken its number, sorry, but it was 820 uF/250V and when I pulled it out it was doing the same rattling sound when I was shaking it that the bad one on the picture was doing..only it wasn't shorted.

Hope this helps someone!

Saturday, April 12, 2014

Hisense 50K360G dead with blown main board SAG7.820.5028/ROH

A week ago a customer brought in a Hisense 50K360G LED TV with the complaint of being totally dead.

At first we thought it would be the power supply, but a quick check on it showed this was not the case.

Before the pictures a few quick notes on the brand, times, politics and other important author observations almost certain not to be closely related to the issue at hand.

When I was in China last year (how many TV repair technicians can say that, eh?) my local guide was Cindy, the sales girl for our vendor partner there. Actually at the time she has already left them and they were a bit annoyed that it was exactly her who was my guide. I choose her because she offered it, I did need a guide (and you would likely need one too!) and finally I did not actually know well their new sales person, which is by rule the only person (or people) in a Chinese company that speak English. Now I know Ana better and I would not mind her being my guide next time around, of course if only she offers it.

Not really sure if both offer to guide me, but rest assured if it ever happens I'd blog about it, under a pseudonym if I must :-)

So Cindy told me that in China Hisense is a popular brand that is considered quality.
I guess kind of like MacDonald in US :-)

Looking at board design and construction I could also tell that either Hisense has been either making boards or licensing TVs to some American brands for some years or , at least, has been using the same sub-contractors to do boards for them as well known American brands.

Which kind of puts them at the same high level.

Which is all to say that I do like that I've seen from the brand. And I also liked the slim and elegant - if not ground breaking - design of the 50K360G.

Only it was dead as a brick.

Here's what we found inside:

Dang it, this is the reason why it is so cheap: there's practically nothing in there!
A good 'ole plasma TV would hardly leave enough room for dust and when you open it you'd have the good feeling that there must be millions of things that could go wrong , they all have to be checked and customer would simply have to pay for all of it...because it was big, stuffed and expensive..and not just big, empty and cheap!

Anyhow, we measured the voltages on the power supply board and they were somewhat OK.

I say "somewhat" because they aren't exactly typical for a TV. A typical TV power supply would have a standby voltage of about +5V, a power board signalling pin that wakes up the rest of the output voltages and lots of connectors and pins on them where you can measure those voltages.

On this TV there was no +5V standby, but there was a power-on pin and that is even more confusing because on standard televisions the power-on pin usually takes +2.5V to +5V (logical 1) to wake up.

On this power supply board one didn't even have +5V handy and passing what was available was against, hmm, commons sense and past experience.

What is available is 12V and 15V if memory serves me well.

Luckily the power supply board specifications are printed on the board itself - BTW another sign for a higher end manufacturer.

TO cut the story again, the power supply board indeed does provide +12V in standby mode and indeed takes +5V to activate the rest (which isn't much).

Also, just like most other LEDs, the power supply produces AC voltage for empowering a chain of LEDs as opposed to DC voltage you'd expect if you just think of LEDs.

Here's a close-up of the main board SAG7.820.5028/ROH (click to enlarge):


And here's a close-up of the top of the board that drew our interest:
 
As you can see this is a fairly well smoked component.
This is the voltage stabilizer that takes the +12V standby voltage and makes +5V out of it.

The same +5V you can use to manually engage the power supply BTW.

Here's our advice: do not try to replace it. The same thing is likely going to happen.

Modify the board to incorporate a more powerful stabilizer or send it to us and we'd do the modification.

We were able to repair the board all right, but there is no guarantee this will always be possible.

After all, when that thing fails, it may short the +12V input to the +5V output, sending the next circuits 140% power increase...and some of them may quit.

None of ours has done it, luckily, but this is what we found when we started the TV again:


Either the customer or we have broken the LCD display and now the TV has the value of my old running shoes, even without the odor!

You know what we did?

We paid the customer $150 for that TV because we weren't certain if it was us or her and we figured we can keep it and do repairs on the main board and the power supply board for people like you.

And I am not making this up.

I must say this is the first time something like that has happened. We've bought broken TVs before, of course, but frankly $150 is fairly high for a TV that will never sell.

Meaning we won't be doing it every time someone brings in a broken large screen TV :-)

Thursday, April 3, 2014

"Please use audio 3 input for dvi connection" message on Sanyo TV

From the mail:

Dear Coppell TV Repair, after further testing the TV myself it doesn't have sound. It has great picture. Model is DP50741, chassis P50741-01, main board J4JF and when I switch to any HDMI input it says "Please use audio 3 input for DVI connection.
Can you fix it?"

Turned out we could.

The problem is not going to be limited to this particular Sanyo model, but since I haven't seen it before in this particular form I decided to post that article and let you know about it.

The board would work just fine on all other inputs, including TV, composite and component. Did not actually try the VGA input, but on the rest it would have sound and picture just fine.

Only on the HDMI inputs it would give the quoted "Please use audio 3 input for DVI connection."

We were split between the HDMI multiplexor, the main processor external memory where various configurations are stored and the standby processor external memory where also various configurations, including, for example, the audio muting selection, is stored.

Well long story short, this time it turned out to be the HDMI multiplexor IC.

Granted , it could have been one of the other two. Or something we didn't think of.

If you're not curious to experiment soldering ICs off and on to find out what caused it for you feel free to look at our board repair services at http://www.coppelltvrepair.com .

And if you feel adventurous then well, good luck and hope this was of help!

Sunday, March 23, 2014

The risks of do-it-yourself bad capacitors replacement

We usually refrain from advertising repair services for boards well known for solely developing bad electrolytic capacitors for the simple reason that we believe in the human nature and the ability to do most simple things like replacing them without external help.

Every now and then, though, I am reminded that what may seem very simple and easy to some may not be so easy and simple to others.

(The last time I was reminded of that, by the way, was just the other day when I was asked over $400 for an installation of a simple reverse osmosis filtration system for drinking water under the kitchen heat sink; that was the cost of the labor only , for about 90 minutes of work. Geez!)

Anyhow, while electrolytic capacitor replacement can be considered as easy as component level repair can be, there are some gotchas to watch for.

One thing I've seen in the past is damaging the copper track on the back, front or inside the hole where the leg of the capacitor goes. On some boards there are tracks on both the top and the bottom of the hole and the hole's internal wall is also galvanized and uses as a normal electrical link between the top and the bottom track. Overheating the solder at the bottom and especially under-heating it and ripping out the capacitor would often tear off the galvanized internal layer and when a new capacitor is installed it may not have connection - and if it does it will definitely not be a reliable one - between the top and the bottom track.

I have seen customers and even technicians send boards to us which are otherwise functional, but do not work because of a torn link between top and bottom layer when pulling out a component.

Of course this can happen with any other type of component, not just capacitors.

Here is something, however, which happens in particular with electrolytic capacitors replaced with ones of lower breakdown voltage:

The board in this picture is PS-507-PHN  / LJ92-01513A, but the same could happen with any other board where electrolytic capacitors are replaced with ones of lower breakdown voltage.


The traditional way of blowing an electrolytic capacitor is to reverse its polarity, switching the positive and negative legs. It's very easy to do and sure enough even we do it sometimes.
When put to work, the cap starts heating up quickly and the top swallows.

 
The capacitors on this board were properly aligned, though, but severely under-rated.
Original ones were for 50V and they were replaced with ones for 16V.
It must have been a loud and smoky explosion and as you can see this poor guy's internals are all over the place.

This picture is just a reminder that when you pull out a board for service it is also in your own best interest to give it a little cleaning.

When the capacitor has exploded part of the foil from its outer body has wrapped itself around a nearby diode. This may actually result in a shortage and needs to be removed.
Other than that and the mess exploded electrolytic capacitors are actually not much harm for the circuits.
 
 

Friday, March 7, 2014

Upstar P250WT LCD TV turning off or losing display problem

For those who privately or publicly doubt that I only write this blog to promote Coppell TV Repair offers and services: here is a post about something that will hardly ever turn into a commercial success yet is still both useful and fun!

And lets one show off , of course :-)

THE PROBLEM
A customer brought in an Upstar P250WT LCD TV which, he said, was turning on, showing an Upstar red logo and then turning right back off. A nice sleek TV, which he said he liked (and we did too, once we saw it).

We generally do not service anything below 32'' these days for it is cheaper to buy a new one (even though it'll likely last less than a properly repaired old unit), but we must have been high on that day and somehow took it in.

Our hope was that it was a typical bad power supply capacitor problem, but as we quickly found it wasn't: the power supply of that TV is external and the kind you hardly ever see developing such a problem.

So we opened it up and started experimenting.

THE RESEARCH
Unfortunately we didn't take pictures at that point.

We found that despite of its extremely low thickness the TV was actually with CCFL powered back light and not LED or DLED as we thought at first.

The backlight inverter LCD220D-000A is on a separate small board, which is taking power (and , apparently activation signal) from the main board.

We saw traces of heat around one of the transformers and assumed that was the problem, but true to the advices we ourselves give to unhappy eBay customers ("read, do not assume!") we decided to run a few tests before searching for a new inverter board.

What we found out was this:

First, the signals going to the inverter board are extremely simple: ground, 12V (power) and an activation signal telling the board to turn on. No feedback whatsoever.
What that automatically means is that the TV should be able to come on and stay on (even without backlight) if the inverter is disconnected from the main board, thus preventing power overload in case of a problem.
So we did the test and the TV did stay on, ruling out the possibility of a bad main board.

Second, we noticed that when cables were connected normally, the display was actually coming on for a 1-2 seconds, showing "Upstar" before the TV would shut off. (note this may actually vary depending on the failure)
We disconnected one of the two output sets of connectors and the effect was the same, with the display being just slightly more lit.

When we tried the same with the other set of connectors the display did not lit at all.

So it was either the CCFL or one side of the inverter that was causing the issue.

Third, we pulled out the inverter board and swapped place of the output connectors (we can do that since the inverters in most LCD TVs don't know what exactly are they powering, let alone one in a cheap 25'' unit) and ran the same procedure.

This allowed us to find that apparently BOTH sides of the inverter were igniting the lamps and that one of the lamps (or one circuit, we did not know until we opened the backlight assembly) was not working regardless of where it was connected.

Voila, we knew where the problem was - a bad CCFL!

We called customer and told them this is pretty much a lost cause and if they please want to come back and take the TV; he didn't respond and a few days we called again, still to no avail.

Hope he's all good, but eventually we opened the TV to see if we could maybe eventually, hardly-yet-why-not-try-it, fix what's wrong and fix it.

THE EVIDENCE
Long story short we ended up disassembling the backlight.

CCLFs turned out to be extremely thin and there is only two pairs of them - one pair at the top of the display and one pair at the bottom.


The display's backlight is a solid plastic with several sheets behind in order to disperse the light (sorry if I am using the wrong term...I was writing software in most classes at high school which were not related to math, current or computers and that included most sections of physics too).

What ended up being at fault was one of the two pairs.

Often times with classic CCFLs the problem is actually bad contact between the lamp and the wire/socket and that's often times solvable with nice cleaning and soldering (it is another story that it is not worth doing with today's TV prices).

Here, though, we actually broke the pair of lamps before we could even attempt a repair.

The other half we salvaged and will likely put at our eBay store, but I will make sure the listing warns of the high risk in attempting repair on those and it will be an AS-IS, no returns sale due to same said risks.

While definitely doable if one takes the time and patience to do it, I do not think this is a commercially viable repair service and we will not be offering it.

THE SOLUTION

We ended up with a good display TV that was not quite repairable as lamps were nowhere to be found and installing them would have been a PITA anyway.

The natural course should have been to just sell either the parts or the whole TV on eBay AS-IS, but we opted for something else.

We took an old 26'' Sanyo with broken display and morphed the Upstar P250WT into it.
In the past I've written an article about a similar Frankensteinism with a high-end Sony TV.

This time we had to take out the LCD panel out of the Upstar and put in the place of the broken panel from the Sanyo. They didn't quite match in size, but there are ways to get around that, including using black electrical insulation tape , so we did. Not the most elegant or the most reliable approach, but definitely fast and - so far - working one.

Then we had to do a little research on the main boards, some patching etc. stuff you don't really care for.

The outcome, in a few pictures, is shown below.

I would say it is not worth the time from a commercial standpoint, but if you've given up writing software (even if for a while - 4-5 years perhaps) it is totally worth the fun.








Wednesday, February 5, 2014

Testing BN44-00161A , BN44-00162A and other boards for Samsung HP-T5034, HP-T5064, HPT4234X and others

This is a quick how-to article on how to test power supply board BN44-00161A / BN44-00162A and the number of other boards with the same connector and sometimes functional parameters.
At the end of the article there are links for repair kits, repair service and exchange services available from Coppell TV Repair.

Everything stated here in regards to testing here also applies to Samsung power supply boards BN44-00160A and BN44-00188A , which have the exact same form factor and connectors as BN44-00161A and BN44-00162A.



The list may not be complete, but the principles in testing are going to be pretty much the same for all other boards that look similar and have the same control signals, even if marked slightly differently.

Still, responsibility for transferring the knowledge and experience from here to another power supply board is yours...we only guarantee it to have been tested on the models mentioned here.

Please note that the fact that the boards are tested in the same fashion does not necessarily mean that they are compatible with each other! For example boards for 42'' models are likely going to be overloaded and shut down or burn when loaded on a 50'' model that requires more power.

Some of the TV models that utilize the boards covered here are Samsung  HPT4234X/XAA, HPT4254X/XAA, HPT4264X/XAA, HPT5034 (HP-T5034), HPT5044 (HP-T5044) and HPT5054 (HP-T5054).

The test described here is going to be very useful for owners of the 50'' models which are known to develop a problem with the Y-Main / buffers trio, which is often confused and blamed on the power supply, which actually fails relatively rarely compared to them (apart from a known simple issue with bulging capacitors visible to the naked eye).

On the other hand, the 42'' models have a known widespread problem developing in the Va tract of the board. It does not affect the 50'' models nearly close as bad.

Step 1 - connecting to AC power and obtaining standby foltage
Disconnect all cables from the board. You may run the test while the board is mounted in the TV or taken outside of it. In either case the only cable from the TV you will need is the AC power supply cable.

If you connect AC power to the board now it should not respond in any way you can see or hear, but if it is functional you should be able to measure about 5V DC between the STBY pin and any of the RTN pins on the white connector CN807 at the lower end of the board as shown here:


Instead of using RTN you can use the metal piece on the right side of the connector at the corner of the board, which is supporting the screw used to fasten the bolt to the chassis or you can use any point from the TV's panel or chassis as well if the board is mounted in the TV.

Also, you should get between 2.6V and 5V DC reading on the PS-ON pin (again to RTN).

If you do not get any of those two and are sure you have AC power supplied properly then the standby voltage of your PSU is not functioning and needs service or replacement. Troubleshooting that is beyond the scope of this article, but at the end there are links to our repair services.

Step 2 - activating the power supply board and receiving Vg, Va , audio amplifier voltage etc.

We recommend you do the actions below when the power supply is disconnected from AC power to prevent accidental shortages and problems.

To activate the board one needs to short the STBY pin on CN807 to ground, i.e. RTN.

You can use a wire from a cable as one shown here and which is what we used for this pictorial.
Be careful and make sure you do not short out other pins on the connector!

There is nothing special about this wire and you can get one similar to it from an old unused ribbon cable or order two for a dollar if you want.

You can probably also use a simple jumper used in older IDE hard disks, computer motherboards and other electronics for configuration selections.

So with either a wire or a jumper you short the PS-ON and RTN pins (any of the RTN pins would do) on the connector like this:



When you short the two pins and supply AC power to the board it should click once (or could be twice , really fast, as it has two relays and sometimes one of them may respond with a slight delay...it can still be considered ONE click, though, even if a double one) and then stay silent; if you have a good hearing you may hear a quiet buzz coming from the board.

If you have a voltmeter and more curiosity you can venture into measuring voltages as explained below.

All output voltages except Vs should be present and you can measure, for example 67V or so between Va and GND on CN808 or CN809 and +15V between Vg and RTN on CN809:


Also important, you should be able to measure 18V between the Vamp pins on CN801 and RTN (or chassis). CN801 is the two-row black connector located to the left of CN807 at the low right side of the board and which I did not make picture of, sorry.

The audio power fails very rarely, but if memory serves me well it is not monitored by the board, which means that if is not there the board would remain on, which would lead the TV to turning on and then off as the main board will shut it off noticing the lack of Vamp...yet the symptom would point to a faulty power supply board.

Anyhow, if the board is OK you should hear it click and be able to measure those voltages.

If the board is not OK then it will either remain silent (rarely) or there will be one click (or one double-click) followed, after a second or so, by another click / double-click.

The second click indicates the board's protection has kicked in and shut it down. The board would then need a service or replacement - see the end of the article for that.
Troubleshooting is beyond the scope of this article.

Step 3 - activating Vs

Vs is the highest and most powerful output voltage of the board. It can not be produced if Va is not functional (not without tweaks on the board anyway) and often times the presence of Vs is considered the ultimate test for board's functionality. That can be misleading as noted in the Vamp note above, but for practical purposes is pretty darn good.

Again we recommend performing the step below when the board is disconnected from AC.

To get Vs out of the board you need to have the board activated (PSON to RTN) and VS-ON from CN807 supplied with +5V. You can use the 5.3V from the last two pins on CN807 or the STBY pin.
We use the later for our test:




Nothing different should be seen or heard compared to activating the board in step 2, except maybe a slightly different buzz to the experienced ear.

Upon connecting AC, if the board is good it should again click once and, shortly after, Vs should appear on CN810 at about 207V measured to RTN.

If you do not have a volt-meter you can run the ultimate test by simply shorting the pins shown on the above picture, supply AC power to the board, wait for the click, wait 5-10 seconds and disconnect AC power. If the board clicks on again when you disconnect power (this time to release the relays) then chances are very good that the board is functional.

Note this is not entirely true , in a volume sense, to the 42'' models of the boards: they often develop cold solder joints which may appear to work fine in a single test, but would cause problems in continuous use. Of course the same applies for cold solder joints in any type of board, but the 42'' versions are known to develop it...so a single test is not conclusive in regards to a "sometimes works" symptom. It is , however, fairly good for a "reliably not coming on" symptom.


A second click shortly after the first one is an indication of a problem, which, for the last time,we will not be attempting to troubleshoot in this article.

Useful links:

1) Search for what's available at Coppell TV Repair site by board model or TV model

2) Repair, exchange and DIY repair kits for BN44-00161A at CoppellTVRepair.com

3) Repair, exchange and DIY repair kits for BN44-00162A at CoppellTVRepair.com

4) Repair, exchange and DIY repair kits for BN44-00160A at CoppellTVRepair.com

5) Dedicated attention regarding questions and consulting from Coppell TV Repair

6) Samsung HP-T5034 , HP-T5044, HP-T5064 article on Y-Main and buffers

7) Diagnostic and repair service for LJ92-01490A Y-Main for 50'' Samsung HPT5034, HPT5044

8) Upper buffer board LJ92-01491A for Samsung HPT5034, HPT5044,HPT5064 and others

Hope all this helps!

Friday, December 6, 2013

LG 50PG60 plasma TV not turning on, blinks four times - what is the problem and how to repair

It's been a while since I posted in the blog and it's because we are so busy with work lately.

Unlike other articles, this one will not be based on personal experience with this particular model.


It's just a question we received and my answer to it for all I know.

The logic here is fairly applicable to many other similar situations.

Question:  
LG 50PG60 TV won't cut on. The power light blinks four times and that is all it does.

Coppell TV Repair's answer:
First things first: I have to say that I have not worked on that particular TV model. 
When I do I'll revise this page to be more specific.

It would be a good thing to know if the power supply clicks when the TV gets powered on or not.

That would say if the power board is functional enough to at least recognize the power on command and process it to the point where it tells the power supply to wake up.

Here are the most likely possibilities based on experience:
1) A bad power supply board EAY43510801 failing to start up as expected

2) A bad main board fails to either wake up the power supply or continue the TV initialization process once power is generated.

3) Another failed board preventing the TV from coming up as being detected by either power or main board and causing it to signal error and shut off.

Let's quickly review the three possibilities and how do you test and eliminate each with what's handy:

1) A bad power supply board EAY43510801 failing to start up as expected  

With the note that I have not worked with this particular board, I've worked with several others that are used in brother and sister models of the LG 50PG60 and I would hazard a guess that the PSU (power supply unit) EAY43510801 can be tested fairly quickly and easily.

I won't type the details again here, but you can read one of the following articles, which explain it:


http://blog.coppelltvrepair.com/2013/09/how-to-test-lg-eay60968801-power-supply.html


http://blog.coppelltvrepair.com/2013/06/question-about-repairing-power-supply.html

http://blog.coppelltvrepair.com/2013/04/lg-50pg20-not-turning-on-is-power-board.html 

They all say basically the same thing, so it shouldn't be hard to apply to EAY43510801at all.

If the test doesn't pass you can contact us for a repair service on your EAY43510801.

Until we gain some hands-on experience with the board there won't be a listing for it, but I can tell you that we can't charge more than $70-$80 for repair for purely practical reasons. If we can't fix the board or it is too costly to fix the only thing you'd end up paying is the return shipping for the board - no parts and no labor.


2) A bad main board fails to either wake up the power supply or continue the TV initialization process once power is generated.
That can be somewhat hard to test and frankly the best thing to do is to leave that option for the last and rule out the others.

Short of hearing or seeing someone who's seen this problem multiple times and telling you what exactly to look for the best way to test a main board for an issue is to have it replaced with another.



3) Another failed board preventing the TV from coming up as being detected by either power or main board and causing it to signal error and shut off.

While this could be any board that is monitored (and the power supply board monitors most if not all of its output voltage lines) the two most likely candidates for that are the two boards that consume most power and those are the two sustain boards - the YSUS (Y-main) and ZSUS (also called X-Main).

The below instructions are only focusing on testing the YSUS and ZSUS boards. That leaves open the possibility of another board causing the failure, so do not forget about it if all tests here pass!

YSUS in 50PG60 is EBR41728701  and ZSUS is EBR50044801, but you won't need those numbers before you suspect any of them as a problem.

A sustain board can be bad in different ways and can cause different misbehavior, but specifically when TV does not come up (meaning front LED not staying in solid "on" state - blue or green or whatever indicates "on") then there is a relatively simple way to see if a sustain is in the way: disconnecting it from the power!

I instantly want to note that this is not true for all TV makes and models. Panasonic plasma TVs usually would not tolerate, but most LG based plasmas and many Samsung ones, especially older ones (I just haven't seen enough of the generations after 2009 to know) would also allow it.

So in a nutshell you just disconnect the YSUS board from the power supply and try to turn the TV on.
If the YSUS (or the buffers after it) were either shorted or just badly overloading the power supply and causing it to shut-off itself, then by removing them you remove the problem and the TV would happily come up, even without a screen.

If so then you know you have a bad YSUS and/or buffer boards.

If so you can search for EBR41728701 and possibly the buffer boards.

If no help, then you usually want to connect the YSUS back to the power and disconnect the ZSUS EBR50044801 for another try.

Disconnecting the power supply only is usually sufficient. Sometimes - rarely yet sometimes - you'd have to disconnect the data signal cable too as a damage can be showing through it and causing the shutdown.

Basically this is how far I can take you this time...testing the power and the two sustains (with some limiting conditions) as the most common sources of problems in plasma TVs.

If those quick tests don't help I'd go for a commercial advice.

Good luck!