Sharp LC-46D64U Image flickers then dies

[Mikey130]

Hello, I have a Sharp LC-46D64U that I recently acquired that is having some weird problems. When I first received the Television set I could not get any signs of life besides the power light, which flashes green at a steady interval. After some research I discovered the reset trick, (Channel down, volume up or the other way around while powering up the set.) After doing the reset I had some signs of life and thought I had fixed the set. My excitement was short lived, the set powered on, flickered 3-4 times then died. I could make out the input selector menu before it died and that was it. If the set is power cycled then the same results will occur. Occasionally it will go back to the power light flashing, which I assume is some sort of error code but I can not find out what it is. I pulled apart the set figuring it might just be a bad cap or something having fixed a couple monitors and sets before with bad caps/boards. To my dismay it had no bad capacitors or anything obviously wrong with the boards. After this I began research and troubleshooting, I've done the following:

-Checked Pre-power board, it is outputting 120 volts as desired.

-Checked all outgoing voltages from the main power board, all are within 1 volt of desired voltage.

-I have unplugged all input/tuner boards and received the same effect so I do not believe it is them.

-If I unplug the TCON board I get similar results before the set shuts off 3 flickers in and throws me a error code, so I do not believe it is the tcon board but I am not sure.

-I have also noticed the mainboard has two red LED's that turn on and off seemingly randomly while the set is on, I don't know if this means anything.


Any thoughts on what the issue might be and how to troubleshoot further? I've read some places I should check the transformers on the inverter board but I do not know how I would go about this. Any help would be appreciated, thank you.

[martyparish]

Re: Sharp LC-46D64U Image flickers then dies

Have you tried unplugging the inverters and then powering up w/ main hooked up?

[randtek]

Re: Sharp LC-46D64U Image flickers then dies

You haven't been very specific about the LED flashing, what error code are you getting? Is the green LED flashing fast or slow? I think you are probably looking at a lamp error, if the green LED is flashing at a steady rate of 1 flash/second. To get the most help, you should submit some good clear photos.

[Mikey130]

Re: Sharp LC-46D64U Image flickers then dies

Marty - Unplugging which cable, the inverters all together?
randtek - It would be hard to display the flashing in a picture, I will post a video tomorrow, I would say 1 flash per second.

[randtek]

Re: Sharp LC-46D64U Image flickers then dies

Marty - Unplugging which cable, the inverters all together?
randtek - It would be hard to display the flashing in a picture, I will post a video tomorrow, I would say 1 flash per second.

Sorry, I was not clear. I meant photos of the boards and the back of the set with everything connected. Clear photos with enough resolution to read lettering on the boards.

[drpj23]

Re: Sharp LC-46D64U Image flickers then dies

1 flash per second is an inverter failure
On Sharps it may be worth it to check for bad CCFLs

[tieny]

Re: Sharp LC-46D64U Image flickers then dies

I'm guessing most likely a loose ccfl lamp connection (could be a bad lamp also). Or a bad inverter board (a bad transfomer on it).

When the set flickers and then goes off, try shining a flashlight and see if you can make out any pictures on the screen. (still could be hard to see) If you can see a faint picture then the problem would be with the ccfl or the inverter board.

[Mikey130]

Re: Sharp LC-46D64U Image flickers then dies

The flashlight test was one of my first tests, I will repeat the test though just to make sure. Also how do I test transformers, can i test the whole board at once or individually? Also where to the CCFL's connect?

[drpj23]

Re: Sharp LC-46D64U Image flickers then dies

If it goes into the error mode (flashing) after the flickering then there will be no visual since the set is shut down.

[tieny]

Re: Sharp LC-46D64U Image flickers then dies

I had a sharp that turned on for a second with a green led but then the screen went dark and the led went blinking red, but I did still see snow on the screen and the input menu. Not sure but I did find it odd. It turned out to be a bad transformer on the inverter board.

You can measure the resistances of the pins of the transformers and compare them with the others.
But sometimes I find it difficult to test transformers... I measured the pins before but it read out of range for my meter. (or it was just open circuit but I wouldn't know)

Or the tedious way, You could tear down the TV down to the backlight ccfl's, (The lcd panel is extremely fragile!, so careful with it and the tab bonds on the sides of it) then plug in the TV and see if you can see if there's a bad ccfl.

[Mikey130]

Re: Sharp LC-46D64U Image flickers then dies

Mmmkay I will try testing the transformers, I take it that I have to take the inverter boards off the TV to test them? Also pictures are being a PAIN to upload for some reason, I will try and upload them tomorrow from a different internet connection.

[Mikey130]

Re: Sharp LC-46D64U Image flickers then dies

Pictures don't want to upload so I will have to use my phone, what pictures specifically will be helpful so I don't use all my data up? Also tested the transformers and didn't get any extremely abnormal results, all are within 10 ohms of each other.