How to uninstall 6871QYH053B and compatible boards from 42'' plasma TV

People often ask me how to uninstall the YSUS board 6871QYH053B (or some of its compatible models - 6871QYH048B for example) from their 42'' plasma TV.

Coppell TV Repair services those boards and the question is natural considered we expect you to send us the board for repair.

This is a really quick tutorial that is board-independent and TV model independent.

It is important to say that while different board models do not have any differences in regards to dismantling procedure, the TV models may make it a bit different as to how do you get to the board.

Again, this short guide is aiming at all models and I will point out where differences are expected.

To uninstall the board, first lay the TV flat on the floor, face down.

Unscrew and remove the base, as most of the time it gets in the way. Sometimes it does not, but we usually remove it when we work on a TV.

After taking all the bolts of the cover (and sometimes ones that we shouldn't take out) and removing the cover we look at something like this:

On all plasma TVs that I have seen the YSUS is on the left and the ZSUS is on the right. They look differently in different makes and models, but they are always left and right and YSUS is always a bit bigger than ZSUS.

Otherwise they share a lot of functionality and, logically, appearance.

Anyway, the trick to pulling out the YSUS is usually getting access to the lower right corner of the board where there's a screw in the corner and - in this case - a very fragile flat ribbon cable connector.

To get to there, you often need to uninstall and move the whole central block assembly containing the main board:

In this case, there were two bolts on each side that were holding the assembly, plus three more on the bottom that were holding an L shaped metal supporting the assembly by tying it to the chassis.

In your case this may be slightly different and in some cases you may also need to remove the vertically standing support bar used for both wall mounting and construction support. At least we've done it a few times but most of the times - possibly always - you can get away without having to do that.

After all the bolts affixing the main board assembly are removed, you can simply pull it up and/or push it to the side:

As I said what you're aiming at is access to the lower right screw of the YSUS board and, of course, the fragile connector P8 just above it.

This is how the beast looks up-close:

Again, it is OK that your cable is white and ours is not. We're the pros, we can afford better cables, wink-wink.

The cable in your TV will likely be white and not orange-brownish as in our picture. Do not pay attention to the color and please do not call to ask if that is a sign of anything. It isn't.

To uninstall the cable, you need to flip the right side of the brown plastic covering the flex cable so that from horizontal it turns vertical. The hinges are at the ends on the left side and are extremely fragile.

I hear there are special tools that let you open it, but I am old school with fingernails and do it this way:

If you can't make a difference between the two pictures, look at how the brown cover is already flipped up on the second one.

The trick for me is to have relatively wide access of the force that pulls up and to also push a little bit inwards in addition to upwards.

Wide contact is necessary so that you actually make the whole length of the cover to wish to turn up. If you apply force only in one point in the middle the brown cover will likely bend and break the hinges.

So if you are using a screwdriver make sure you get one with wider tip.

A great idea is to use two fingers if you can do it - pointing and middle finger work great.

MLT168A power for ILO LCT27HA36 , AKAI LCT2785TA - how to test and more

MGMEET MLT168A is very similar to MLT166A about which I had blogged before.

Here is how it looks from the top:

The power input is the single one at the upper left corner, just below the top edge of the board. Its pins are marked with N and L.

All the outputs are on the right side of the board.

When AC is connected to the board there is a single 5V output and it is on the connector marked CON3.

Those 5V are called standby voltage and are used to tell the power board, through another pin on CON3 to wake up and generate all other voltages needed for the normal TV operation.

Using a voltmeter you can check if you have 5V on the appropriate pins on CON3 as per the following illustration (click to see full image):

So, once again, when power board is supplied AC the only output voltage that should be there is the +5V standby voltage. Using a voltmeter you should be able to measure 5V between either of the two pins as displayed above and the ground (which is any of the Ground pins or the TV chassis).

To turn on the rest of the voltages you need to pass the +5V from the standby to the POWER_ON pin.

If there's a cable plugged in in CON3 you can use a wire to short those two. It's OK to short +5V directly there for reasons we will see in a minute.

We didn't have a good connector so we turned the board and soldered a short wire between those two.

Here is how the back of the board looks where the output connectors are:

And here is what it looks like when we passed the +5V to the POWER_ON pin:

While usually it is not recommended to pass +5V directly to anything (just out of precaution) in this case it is easy to see that there is a resistor (R133) at the input of the POWER_ON line. This means it is completely safe to pass +5V directly there.

Once you have signaled (turned on) the power board you should be able to measure all other voltages as indicated at the top side of the board near the connectors - +12V, +9V and +24V.

Note they may be slightly off the printed values. If you get 11V instead of 12V that's OK as long as it is stable.

If it fluctuates or if it is off by more than 10% you've got a problem.

And if you've got a problem you know who to call.

No, AFTER the ghost busters!

Repair, trade-in or buy - comparisons and explanations

Dear coppelltvrepair,

Do you guys have any of these (6871QYH039A 6871QYH039B or 6871QYH039C ) in stock to ship out now or would you have to wait to get mine and then repair it and then ship it back to me?? I need this fixed as soon as possible, I have a customer waiting on it. Thanks a lot :)

- fsm_derek

We often receive questions like that from customers and service technicians alike.

Naturally, everyone likes to get their TV working ASAP.(*).

In fact, I have blogged about that earlier, giving an answer to customers requesting that a board is sent to them before their board reaches us.


Now I'd like to take that a step further and explain how we see things.

When getting a new board a customer has four major options: purchase, repair service, exchange service and trade-in service.


PURCHASE is the typical and most common American operation, along with trashing. I.e. you purchase what you need, wait until you receive it and then dutifully bring to the trash whatever was in its place before that. (**).


The EXCHANGE SERVICE , as the name suggests, suggests that you send something in and get a working version of the same thing in its place. Usually the logic is that the replacement is sent as soon as the exchange is received and most customers really want to do it even only with a proof of shipping or "are used to doing it that way with George Electronics" (***).

Coppell TV Repair used to do exchanges until we realized that 80% of the boards that we were receiving had been worked on, broken, used for parts, shoved in the ground, chewed by dogs and you-dont-want-to-know-what-else.

But you get the point. The majority of the boards we were getting were only good for parts.

There's also another reason why exchange is risky and it is worth for it to be explained, because decent folks who send good boards must also understand why are we rejecting them: boards often have unique components on them.

For example every power board and every plasma sustain board have transformers on them which are uniquely made for that board.

If the transformer burns there is usually no place to get it from. It is made especially and only for that board and since the manufacturer does not want anyone but them to service those boards (****) then the only place to get that component would be another board - working or broken.

As every service center we always have a few broken boards neatly stacked under somewhere around, but problems tends to arise in the same areas of a module and soon we find that all such faulty boards miss the same transformer.

In other words, sometimes we can't restore a board even if it has not been tampered with.

The failure rate is different for the different modules, of course, but the core of the problem is the same: exchange may practically end up meaning sale since what we get back may turn out to be just useless.

Without a source of unique components / broken boards exchange is a risky business for the provider, which is probably why it is not at all popular in this business.

REPAIR SERVICE means that the customer sends in a module, the vendor receives it, repairs it and sends it back to the customer. It's usually the cheapest of all options (*****)  and that is its major benefit.

The drawbacks are that it is slow and also insecure.

It is slow because it takes time from initiation to completion. Module needs to be sent back and forth and that alone kills a good week at best. Then you have service time on top of that.

And this is where insecurity comes - the vendor may be overloaded with work, their testing environment (6) may shatter to pieces (speaking from experience here) or the problem on the board may be tricky and take longer to resolve than usual.

Worst of all, it may turn out to be practically unsolvable - see the explanation for the unique components in the exchange service section.

Without complete sourcing solution for replacement parts repair is never guaranteed.

At the time of writing this article none of the repair services that we offer is completely guaranteed!

There is more to be said about repair services in general, but the take-away from here is that it is cheap because it is not secure. Vendor can always call customer, apologize and cancel (7).

The TRADE-IN SERVICE is well known and widely used. The first that comes to mind is car dealerships: you get raped on the way in and on the way out.

That's how I used to think until I got in the repair business..

Customer orders a board and expects to receive it before the vendor receives their board back.

Customer is OK with the concept of having to pay a bit more upfront, but expect to get that recovered upon their board's arrival.

But for reasons explained above (can't argue with statistics!) it is not only easier, but I'd say a must for the vendor to assume that what they'll get in is a junk. Even if it does look OK, you can only know if it's OK when you do a full service on it - and by then it may be too late as you'd have already spent time and money on trying to restore it.

The bold conclusion is that TRADE-IN and EXCHANGE services CAN NOT cost as much as a REPAIR!


TRADE-IN and EXCHANGE offer less waiting time (no shipping back and forth) and less risks to the customer (board that's coming has been serviced and tested).
In a free market that ultimately translates to a higher price!

How much higher? Well the extreme is the price of the core - the bare defective board. Usually it is less.



This has become another lengthy article with many undefined assumptions and still doesn't say even half of what I want to say on the subject.

But I'll stop here and imagine I am trying hard to learn to express myself more simple and clear in future.

Gosh I love leaving comments under line! (8)

Thank you for reading all the way up to here...your thoughts are appreciated!

- Bobby

________________________________
* Otherwise bad things may happen. Like looking out of the window, reading a book or, God forbid, dropping by unexpected by a friend just to say hi.

** Does not apply to spouses, gym subscriptions and HOA dues. Otherwise would would have been perfect.

*** To which we automatically reply "then why don't you keep on doing it?!". Poor George Electronics!

**** Service?! "We recommend you replace all three modules", says the manufacturer. "And that's a total of $350".  Which is only 80% of the cost of a brand new TV with a year warranty. It's good to be a manufacturer in a world of AOL users!

***** Unless, of course, provided by a authorized/certified/glorified dealer.

6) Sounds more complicated than "TV".

7) "Sorry, dude...it's a bad mess...been working on it for 10 hours and it wouldn't bulge. I give up and you owe me too much, but if you give me $100 I won't press charges for more..."

8) I warned you!

HP PL4260N suddenly lost picture - how to identify failed sustain boards

Synopsis: this article discusses the most popular failure in HP PL4260N (and the bunch of other TVs based on the same plasma display set by LG), the means to diagnose which board has failed and provides links for repairs / replacements for the failed boards.

Question:  I have an HP PL4260N plasma TV  (purchased 2006)  that has suddenly lost picture.  I don't know whether sound is still there since it is run through a home theater receiver.   I have taken the back off and none of the fuses are blown and there is no obvious bulging of any capacitors ( with one possible exception of a large 450v, 330 mf capacitor... it is so very slight that it may not be a bulge at all).  All fuses (there are 5) show continuity.  When the on switch is pressed it turns blue and then back to red.  No picture at all.

I have read your very interesting blogs but have found nothing specific to my Hp model... some say is was actually manufactured by either Samsung or LG.  I realize the information I'm giving you is sparse but from what I've read, I assume the failure of the Y an X boards as well as the power supply involves the failure of their fuses.... as mentioned, no failure noted.  Should I go ahead and replace the suspicious capacitor as the first step?  What can I do to determine the faulty board or combination of boards and what would each cost to repair.  Also, if a board tests OK by you, what would the charge be for the testing?

Answer.  Yes, this is likely a YSUS or a ZSUS board on your PL4260N.

(for those who do not know what YSUS and ZSUS are, here's a quick pictorial guide:)

A blown fuse is the most common and apparent indicator of a failed board, however sometimes a board can fail without blowing a fuse.

So while a blown fuse is a guarantee of a failure, the lack of a blown fuse is still not guarantee of anything.

Since your TV refuses to power on (going blue and then back to red) that would suggest the faulty board is shorted. When the power component on it has failed, a power semiconductor element there (one or more) have melted and has created a permanent (short) connection between power input and ground.

This is one of the possible outcomes of a power component failure and should not be taken for granted in all cases of a failure, but is still a very common one.

The same shortage is the reason why fuses blow in the first place. In your case, as we said, the power supply board has responded faster than the fuse and shut itself off.

Now when powering on it again detects the short before releasing full power voltage in that circuit and shuts off, which is why you see the TV going from blue back to red in a very short time.

When there is no burned fuse on either sustain board there are two major possibilities for a failure:

1) When the TV would not come on at all
That would indicate that a board has failed and shorted a major power line, but did not blow a fuse and as a result when TV is turned on, the shortage is detected by the power board and it automatically shuts itself down.

It is very easy to figure out the failed board since it prevents the TV from coming up: all you have to do is disconnect first one of the boards from power, say the YSUS board, and attempt to turn on the TV.
If the TV comes on and stays on (of course without anything on the screen) then the disconnected board was the one that was stopping it.

If the TV keeps on doing the same then connect the board back to power and disconnect the other one, then try to power on again.

If TV comes on this time then you've found your faulty board and if it still doesn't then the problem is most likely in neither of the sustain boards (although it is theoretically possible that both of them are bad).

Another simple way to find the failed board is to use DMM to measure resistance between Vs and GND pins on the power connector of the board. Zero or low (ohms) resistance in both directions indicate a failed board.
Please note that this is not the only possible short a board may develop, only the most common one.

2) When TV would come on with black screen or , sometimes, very dim, washed out screen
This is actually the more common failure than the above.
Dim and washed out image is most commonly caused by a failed ZSUS board.
If there is nothing on the screen, however, it could be either the YSUS or the ZSUS board that is bad (and very rarely both of them).

The easiest way to test which of the two may be bad is to let the TV run for 5-10 minutes (with dark screen) and then feel the heat sinks on both boards with your hand.

The one that is not hot is probably the faulty one.

If both are hot then the best thing to do is to send both of them for complete test in an actual working unit.

It is worth noting that a good number of times when the board fails it does not end up being short. It is still malfunctioning, but not necessarily short. Even more, sometimes it may have blown the fuse and still NOT be short. So if you replace the fuse you'd be able to power on all right, but still without an image or - sometimes - with a flashing light on the screen or other defects.

Once you figure our which board is bad - or if you can't figure it and need to check both - feel free to send them over to Coppell TV Repair (see section below) or, of course, any other vendor of your choice.

It is also worth noting that the same thing is going to happen on your other sustain board, so you may consider doing a service on both - one because you must and the other one in advance.

Here's a link to another article discussing the pros and cons of servicing one versus both sustain boards:
http://blog.coppelltvrepair.com/2011/05/should-i-replace-repair-one-or-both.html

UPDATE: here are a few tips on disconnecting the Y-sustain board hopefully without damages:
http://blog.coppelltvrepair.com/2011/03/how-to-uninstall-6871qyh053b-and.html

SENDING YOUR BOARD(S) TO US

We have separate offers for repair of the YSUS and ZSUS boards, however should you decide to do both of them simply send both together, that's all.

YSUS repair:
http://www.coppelltvrepair.com/p/164/1032298-hs-ysus-board-hp-pl4260n-repair-service

YSUS exchange:
http://www.coppelltvrepair.com/p/397/1032298-hs-ysus-for-hp-pl4260n-buy-now-then-return-your-old-board-to-get-credit

ZSUS repair:
http://www.coppelltvrepair.com/p/295/hp-pl4260n-zsus-board-repair-service-dark-image-bleeding-colors

Hope that was helpful!

See you soon!

Samsung 214T LS21BRBAB does not power / blinks once

This is a story about pragmatism. A tiny bit of knowledge sneaks it at some point, but for the most part it's just a story. If you expect ground breaking discoveries, mysterious occurrences or erotic adventures then you should move to some of the next posts. You may have better chances there. Bear in mind I am not promising anything.

A local customer called on the phone and asked if we can fix 21'' LCD monitor.

We told him it's probably cheaper to buy a new one these days, but he said he's curious what could it be and is ready to pay our minimal service fee for 32'' LCD TVs for us to take a look.

Monitor was 21'' Samsung 214T [R] S, model code LS21BRBAB/XAA and as customer told us he had looked it up on Google and, upon finding a common failure in the power board caused by bad capacitors, has replaced them to no success. So he wanted us to take a look and even if we can't fix it he'd pay us $55.

For your viewing pleasure, this is how Samsung 214T looks inside:

For the technically challenged and the rest from the normal side of the humanity the brighter thing on the left is a power board and the green thing on the right is the main board.

The power board incorporates in it functionality for providing the special needs of the florescent lamps that provide backlight for the LCD assembly.

Well long story short, the customer has replaced all caps on board and, from the look of it, has done it well.

The monitor was powering on all right, then the display would flash for a split second and instantly turn back again. Monitor would power on and off, just wouldn't stay bright.

Many LCD TVs have the same symptom and the cause us, overwhelmingly, in the circuits that provide power to the back light lamps. In large TVs they are often on a separate board, but smaller TVs and monitors they are sometimes incorporated in the main board just as shown here.

There are several reasons why something like that would happen and before troubleshooting it I took a quick peek at the power board. I was looking for a board label, something that would allow me to look it up on eBay and see what would it cost.
What I had come across was a label NB-20 towards the top of the board.

So I looked that up and a single result showed up offering me a "TESTED, WORKING POWER SUPPLY BOARD NB-20". It was asking $69.95 plus $9.95 shipping. Here's the actual link.(bear in mind it may be invalid by the time you read this).

$80 is a lot of money for a 21'' LCD TV. Way too much in my book.

But then again the link mentions that this is board "IP-58130A", so I searched for that.

Bingo! $26.99 direct from China, 20,000 sales seller, 98.8% feedback.

Reserved as I am , I think this is a no brainer.

I put together the TV as quick as possible and plan on telling the customer to pay me our standard fee less $27 and get a new board from there.

It's not about the money...and I know I can fix the damn board.

I just don't think I can do it the first time for under $27.

If you consider buying parts from China consider this

Next time a customer complains that they received some of our ICs with bent legs I swear I'll send them here to
see some of the REAL problems when purchasing parts.

All of the below are sold to as for "new" and, if you can believe it, prices are as for "new".

After 2 didn't work right out of the box we took the freed to cut them open and then picked another two from the same box and opened them WITHOUT INSTALLING AND TRYING THEM FIRST.

I guess it is not hard to predict what the fourth IC on the image below will look like inside, is it?

 

Rust on ESD components, rust on pin solder connections...

Notice how the original black filling of the IC is covered with a thin layer of a gray one.

There are several take home lessons from this:

1) Buying from China is risky. And it's not because your Chinese partner necessarily wants to trick you. Those parts were received from a company we've been working with for some time with and we do not doubt their honesty.
The problem is they themselves aren't good enough to filter the bad parts that they purchase.
And because we've tried several different vendors we can say this is the common situation out there.

2) It pays for a customer to purchase parts from a company that actually uses them in its own work. If we had sold those parts to customers and we haven't had to use them ourselves we'd probably be doubting our own customers' honesty when they call back and say that apparently brand new working parts do not work.
But since we use them ourselves we act as a first line of quality assurance for customers.
When the product you're buying is not only valuable, but greatly affects the time you spend on a job it does matter to know you're getting quality stuff.

3) Next time you want to save a penny - or even a dollar - by buying directly from China consider all the headaches that a local American company saves you. Not to say all American companies are perfectly well equipped to know the difference between good and bad parts...not at all.
But it's it's still a whole lot easier to hold a company responsible in America than in China.
And frankly, if there was an American company that could offer us the parts we need at decent prices we'd sure be buying them from here!

MLT166A POWER BOARD TEST AND REPAIR - AKAI LCT2701AD and LCT2701TD

A company has sent us a bunch of those boards to repair and we are sharing some of our expertise on how to test and repair them.

Those supplies are used in AKAI LCT2701AD and AKAI LCT2701TD models.

(If you need Coppell TV Repair to repair your power board please first make sure it needs repair as per the below instructions and then contact us to arrange repair. From what we learned odds are good it may indeed be faulty.)



Indeed, this is apparently a poorly made power board because all of the ones that we received had been previously serviced already.

So how do you know if it works?

TESTING POWER BOARD MLT166A
When connected to 110V AC through the main connector CON0 (at the lower right corner on the picture) the board is only supposed to produce 5V standby voltage. This shows up on connector CON2 which is the second white connector from the top on the left side of the board. It is between the two heat sinks and next to the order of three capacitors EC18, EC19 and EC20.

When testing the board we recommend that you disconnect all load from it, i.e. unplug all connectors except the one that feeds AC power in.

The CON2 connector has 6 pins organized in three groups of two pins like this (starting from the top):

* STB (aka PS_ON)
* STB
* GND
* GND
* +5V STB
* +5V STB

The lowest two pins is where you get the standby 5V power. You will need a digital multimeter to measure them. It is OK if reading is 10% off, i. e. anything between 4.5 and 5.5 V will do as long as it is stable.
To measure the voltage you connect one probe to either of the +5V STB pins and the other to either of the GND pins.

To activate the power supply (which is what happens when you pres the POWER ON button on your TV) you need to pass the 5V to any of the two STB pins.
We do that by simply soldering a resistor of about 100 Ohm between the two opposite pins of CON2, but you can as well just short them - in this particular case.

Once you do, the board should start making a humming noise and the rest of the voltages should show up:

CON1 has 3 sections - 3 pins for +12V, 3 pins for GROUND and the rest for +5V:
* +12V
* +12V
* +12V
* GND
* GND
* GND
* +5V
....

CON3 and CON4 each have half of their pins for GND and other half for +24V needed for the inverter boards.

If you get all those voltages then your power board does not need a serious servicing.

COMMON PROBLEMS WITH MLT166A

1) Probably the single most common problem with those boards are bad electrolytic capacitors. You should check and replace those regardless of whether the above test passes or fails. Bad capacitors can change board's behavior under load and can render it useless even if it passes the simple no-load test.


Electrolytic capacitors are the cylinders with shiny tops that can be seen all over the board.

Bad ones can usually be spotted by their bulged tops compared to the other, normally flat ones.


Behind the above mentioned connector CN2, for example, is a trio of capacitors that had to be replaced (or was already replaced) on any single board that we've seen. Those are EC18, EC19 and EC20.
Originally they are rated 1000 uF / 10V each.
If you need to replace them, you should replace them with 105 degrees , 1000 uF or slightly more and at least 10V rated capacitors - the higher voltage, the better (bear in mind they get larger though).

Since EC18 and EC19 work in parallel it is also completely acceptable to replace both of them with a single 2200 uF / 25V capacitor that will work better and last longer.

One one of the boards we serviced we've also had EC11 apparently bulged so we had to replace it as well.

On your board you may have yet a different one that needs to be replaced.

If you need parts, let us know and we can sell and send them to you!

2) The 5V output on CN1 (the lowest 5 pins of the connector) provides power to all the logic functions needed when the TV is working. They flow through a power transistor located at the back of the board which carries both filter and control function.

Simply said, think of it as an operating switch which has 3 connectors - input, output and a controlling (gate) connector which tells it when to activate.

That transistor is apparently badly rated because on many of the boards we received it was bypassed by simply shorting the input and output and completely ignoring the switch control input:

While rude, this solution is a cheap and efficient one if you don't see the 5V at the connector of your board , but you see them on CN2.

If both of those fail to help you, we'll be glad to try our luck diagnosing and fixing your board for $50 or so.
Just send it over!