Sharp LC-40LE810UN question

[olegi]

Re: Sharp LC-40LE810UN question

Please check this
http://www.ebay.com/itm/Sharp-RUNTKA...item2ec311b3ab
First contact him to make sure is working board (low feedback)

[tibimakai]

Re: Sharp LC-40LE810UN question

You think that I should buy another one?
I went that route ones and did not work out. I could have asked that store to send me another one.
In my opinion we should look into why the 400V is not turning on.
I have all the right voltages(except the 400V) until the error code is tripped.

[masaudio]

Re: Sharp LC-40LE810UN question

Read this thread with interest, as im working on a similar tv, LC-40LE811E..
We have a working power up but no backlight voltage, maybe similar to what you have experienced..
What you havent been able to grasp is that the 13v etc disappearing is a normal function when the set doesnt power on..
Those voltages are NOT meant to be running permanently.
only the 5v standby will always be on, the others are switched off until required.


Anyway the UK set doesnt appear to get an error code system like your versions..
This one I have only flashes 2 times continuously.. there is no short and long pulse.

From checking the circuit we do not get a startup voltage to IC7601, the DDA002C
tried shorting that opto as mentioned in an earlier post and we do see a sudden spike from the backlight LED drive sockets L1, L2.

We are getting all other outputs from the power supply, just not this LED driver circuit.
Would be nice if we can get this board fixed, as here in the UK the new board is £260 GBP..

[tom66]

Re: Sharp LC-40LE810UN question

Could be same problem lots of new LED TVs have -- shorted LED strips to the chassis. Does LED voltage come up when the LED strips are unplugged?

[tibimakai]

Re: Sharp LC-40LE810UN question

I'm on hold with this TV, since it's way over my head.
Eventually I will get back to it later on.
I would appreciate any input do you have, since I'm not an experienced repair guy.
I wanted for a while to take apart the screen to check the LEDs, but I was hoping that I don't have to go that far with this repair, but I guess that should be my next step.
I'm kind of lazy these days to work on anything.
I have a Toshiba opened up and I should finish that first, and then I will get back to this TV.
How can I check the LEDs, one by one in circuitry?

[tom66]

Re: Sharp LC-40LE810UN question

Never done an LED TV (currently they go for too much for my liking), but it would be like testing christmas tree bulbs. One by one. 100 LEDs to check. A good DMM, like a Fluke, will light up a white LED on the diode test mode.

[tibimakai]

Re: Sharp LC-40LE810UN question

That is a lot of checking and maybe is not even the fault.
I have noticed that the LEDs lit up with my 87V. I have build like 3 years ago some LED lights for my VW Golf 5 and I have to replace some of them. Yesterday I was checking them out.

[tom66]

Re: Sharp LC-40LE810UN question

Well, if you are lazy, you will never fix anything more complicated than a bad capacitor. What do you expect me to do? Even though I know which it is**, it would ruin the game!

**Foreknowledge can only be expressed after the answer has been discovered. Otherwise quantum lock may occur. And that's really bad.

[tibimakai]

Re: Sharp LC-40LE810UN question

I still haven't get over the holiday laziness. I'm working on some PCs and trying to sell them. These can be done inside the house where is warm, not like in the garage where I should be working on TVs.
I also have another project which I'm thinking to get back to, is a carpc.
An minitx Intel Atom, Windows 7 running on a Centrafuse software for the interface. All the media can be run from the PC, I have bluetooth for the phone, Garmin software for navigation, an HD adapter for HD radio, 41HZ.com amplifier kit, 64GB SSD, 4GB memory, build in wi-fi A,G,N board, 7" Liliput touchscreen and all this is in a box of a size of a double din radio.
All this is the basic unit, from here on you can do even fancier stuff, like controlling your windows, heat/A/C, etc.

[masaudio]

Re: Sharp LC-40LE810UN question

After a bit more work i found out you have to press menu to get the extra error flashes, 2 slow then 5 fast if i recall correctly,

Anyway Today i have repaired this fault.. and it was not too difficult at all.

The error code for Panel Power.. is precicely right..
In my case the 12v supply was low, only 7 volts.

Replaced Q7909, a switchable 12v regulator (13v in, 7v out.. definitely faulty)
Part number KIA378R12PI

and now the set has a proper 12v rail again and fired up no problem..

Hopefully this may help some of you trying to repair this fault without the expense of changing the entire power board.

[tom66]

Re: Sharp LC-40LE810UN question

Excellent information. That's the linear regulator for the 12V. Very odd that that would fail unless it got too hot, which is possible. Did it use a heatsink?

[tibimakai]

Re: Sharp LC-40LE810UN question

Thank you, I will look into it, but I don't remember measuring that voltage.
The error code would come up by itself after like 30 seconds, I didn't have to push anything.
I have purchased another power supply from partstore and with that board I was getting the same code.

[budm]

Re: Sharp LC-40LE810UN question

So where is this Q7909 located at? Is it SMD type?

[tibimakai]

Re: Sharp LC-40LE810UN question

I'm not home with the board in front of me, but looking at my first picture it seems that it's at the bottom left corner under that black heat sink.

[tibimakai]

Re: Sharp LC-40LE810UN question

I have just measured that component and I'm getting 13.5V, 12V, 0V, 2.7V.
The 12V comes on late and cuts off fast as the error pops up.
I'm not measuring less then 12V.

[tibimakai]

Re: Sharp LC-40LE810UN question

Can I try to apply external 12V to that pin?

[tibimakai]

Re: Sharp LC-40LE810UN question

Any more input would be appreciated.
I can turn off the TV from the touch button. I guess that eliminates the main board, no?
It seems that the "high voltage" is not turning on to supply the LEDs.

[randtek]

Re: Sharp LC-40LE810UN question

Inspect the panel closely with a flashlight. 2-5 Error on these is often caused by a broken LCD panel. The panel 12 V goes from the power board to the main, where it is sent to the TCon, then loops back to the main where it is detected. If the voltage is lost anywhere in this path it will give the 2-5 error.

The fact that you don't have to press the power button for the error to start is meaningless. Most decent TVs remember their power state when they lose power, and will try to return to that state when plugged in. Also, many TVs power up the supply momentarily at plug in as a self-test. In normal operation, it will be short, usually less than 1 second. Either of these situations will cause the error to be displayed, without having pressed the power button.

[tibimakai]

Re: Sharp LC-40LE810UN question

I have inspected the panel and I couldn't see any cracks.
I have also tried measuring the LEDs. While some were lighting up, some others I couldn't get to them to measure. They were way to small for my meter's probe to get a reading. They are to many too.
I'm thinking of getting a mainboard. Found one at partstore for a bit over $77.

[tibimakai]

Re: Sharp LC-40LE810UN question

Bud, it wouldn't be possible to make a LED tester? An LED and a resistor to replace the strips inside the panel?
Just to exclude the LEDs to be the problem.
The voltage there, should be around 90V, no?
If I could check the LEDs and they would check out good, I would buy the mainboard.

Another thing that I have noticed, that how come only the mainboard is rusted and not the PS? Maybe it was already replaced by somebody else trying to repair it?