Sharp LC37D44U Power LED was flashing green. TV would turn on, channel indicator shows in upper right corner, sound good, but screen would be black. Channel indicator disappears but screen is still black. After 5 seconds it shuts down. I press and hold power button the Power LED turns red, same power on as listed above. I found suggestion to press and hold Vol Down and Chan Up keys on unit while unplugging the power. Continue to hold and plug power back in, then release. Now the Power LED is solid green, Channel indicator shows in the upper right corner (just like normal), sound is good, no picture or sometimes you can see faint shadowy images. The TV is 22 months old.

Had the same Model last week. Before you go to expense of changing boards, may just require a "firmware" update. Available from the Sharp website.
If you insert a Memory stick..(USB) into the service slot, and the set comes on, may be as simple as downloading firmware and installing.
I presume if you insert a memory stick, and the set comes on that the internal Memory has been overloaded with "****".

Go to Menu/Digital Setup/Check Identification. If it does not show U0904161, you do not have the latest firmware.
Download a "zip" file from Sharp designated as D44UA113.zip.

Much cheaper then ordering a Main board that was probably updated, before you received it.

Regards..

-Ed- Had the same Model last week. Before you go to expense of changing boards, may just require a "firmware" update. Available from the Sharp website. If you insert a Memory stick..(USB) into the service slot, and the set comes on, may be as simple as downloading firmware and installing. I presume if you insert a memory stick, and the set comes on that the internal Memory has been overloaded with "****". Go to Menu/Digital Setup/Check Identification. If it does not show U0904161, you do not have the latest firmware. Download a "zip" file from Sharp designated as D44UA113.zip. Much cheaper then ordering a Main board that was probably updated, before you received it. Regards.. -Ed-

You know thought of that myself so I looked into it and downloaded the firmware update plugged the usb in and plugged in the tv got the blinking green power light held the power button down for 5-10 seconds until the blinking green light chaned to a solid red light then I pressed the button down to turn on the tv and went to Digital Setup and chose update. The tv found the update on the usb drive and started the update with the screen going black then coming back on for a split second only for the tv to shut down completely with out doing the update... Any ideas You know thought of that myself so I looked into it and downloaded the firmware update plugged the usb in and plugged in the tv got the blinking green power light held the power button down for 5-10 seconds until the blinking green light chaned to a solid red light then I pressed the button down to turn on the tv and went to Digital Setup and chose update. The tv found the update on the usb drive and started the update with the screen going black then coming back on for a split second only for the tv to shut down completely with out doing the update... Any ideas