Seeking help on a Sharp TV

[gengtian]

Hi, I got a Sharp LC-48LE653U. Plug in, can see light coming up but no image and the power button not working (won't turn off the tv or turn it on).
So just wondering how to figure out this is the main board problem or PSU not supplying power to main board.
Thanks.
Tiger

[DXseekerMO]

Re: Seeking help on a Sharp TV

The best way to the fastest answer is to remove the back of the TV, take a clear well-lit picture of the layout of all the boards in one picture then take clear well-lit pictures of all the individual boards. Sub-pictures of board markings with voltage values and connector arrangements are very helpful.

Your TV has some sign of power and life so it is presumed the 120V AC fuse is good on the power supply board, but before plugging it in a continuity test can't hurt.

Start by measuring each connector pin on the power supply, positive probe on the pin and negative probe to chassis ground then record and post your voltages in this format: Pin number - voltage stated on the power board - voltage recorded. NC means "no connection", not necessary to post these.

A connector with wires that enter the inside of the panel are for the backlights. The board nearby will likely say something like "LED+" and "LED-" I would worry less about those right now, primary voltages are more important for the time being....but your description sounds like malfunctioning LED's and maybe a button board not hooked up or not working right.

Be careful to look at the power board near each connector to see which pin is number one so when you post the voltages they are for the correct pin.

Be very careful not to short the pins with the tester's probe.

Its also a good idea to check the screws holding the boards down first to make sure they're tight before you first plug it in to do the diagnostic. The boards require chassis ground and must be held snugly to the chassis.

Also a clarification of the symptoms may be in order...."can see light coming up but no picture". Does the light flash once or strobe? Can you see an image on the screen when a flashlight is shined on it? Check carefully and in a darkened area with a clean display panel.

I think Sharp TV's and LED failures go hand-in-hand, just like they best friends!

Hope this gets you rolling!

[Andrew F. Ali]

Re: Seeking help on a Sharp TV

That seems to me to be a Main Bd. problem. Software issue to be precise. Look for a replacement board on e-bay.

[gengtian]

Re: Seeking help on a Sharp TV

Thanks for your detailed instruction. Yesterday after I posted, I opened up the back panel and realized the main board and surrounding area are pretty oily. I guess some time ago the main board went through some overheating and melted the heat sink silicon on the back. I just dumped the TV back to trash where I found it in the first place. The price for a main board replacement is pretty high on ebay.

The best way to the fastest answer is to remove the back of the TV, take a clear well-lit picture of the layout of all the boards in one picture then take clear well-lit pictures of all the individual boards. Sub-pictures of board markings with voltage values and connector arrangements are very helpful.

Your TV has some sign of power and life so it is presumed the 120V AC fuse is good on the power supply board, but before plugging it in a continuity test can't hurt.

Start by measuring each connector pin on the power supply, positive probe on the pin and negative probe to chassis ground then record and post your voltages in this format: Pin number - voltage stated on the power board - voltage recorded. NC means "no connection", not necessary to post these.

A connector with wires that enter the inside of the panel are for the backlights. The board nearby will likely say something like "LED+" and "LED-" I would worry less about those right now, primary voltages are more important for the time being....but your description sounds like malfunctioning LED's and maybe a button board not hooked up or not working right.

Be careful to look at the power board near each connector to see which pin is number one so when you post the voltages they are for the correct pin.

Be very careful not to short the pins with the tester's probe.

Its also a good idea to check the screws holding the boards down first to make sure they're tight before you first plug it in to do the diagnostic. The boards require chassis ground and must be held snugly to the chassis.

Also a clarification of the symptoms may be in order...."can see light coming up but no picture". Does the light flash once or strobe? Can you see an image on the screen when a flashlight is shined on it? Check carefully and in a darkened area with a clean display panel.

I think Sharp TV's and LED failures go hand-in-hand, just like they best friends!

Hope this gets you rolling!

[gengtian]

Re: Seeking help on a Sharp TV

Thanks for your replay. I figured this is likely the problem and on ebay the mainboard cost >100$ and not worth it.

That seems to me to be a Main Bd. problem. Software issue to be precise. Look for a replacement board on e-bay.

[Andrew F. Ali]

Re: Seeking help on a Sharp TV

Sorry to see it go. Thanks for the feedback.