When I turn on my Sharp LC-65Q620U, it shows the SHARP Logo and then turns off seconds later and stays off.
While the SHARP logo is briefly visible the "S" and part of the "H" are partial faded/dim compared to the rest of the Logo.
I have ran into the same problem. Was watching Netflix screen just closed in on itself and turned off. Try turning it back on and it displays sharp logo dimly and turns off and repeats. Found a few threads with this problem that deemed it a bad mainboard after ordering a new one and replacing I am still having this issue. Did you ever end up figuring out the problem ? Has anyone experienced this problem and managed to fix it ?
I have fixed this problem a few hundred times.
First you need to unplug, take of the back, and do a deep-dive visual inspection of the capacitors, especially on the power supply board.
Looking for things like THESE BAD CAPACITORS
THE PROBLEMS YOU ARE TALKING ABOUT WILL NOT BE FUSES.
Any Capacitor without a perfectly flat top is suspicious.
This is one very common problem that happens, if you find any bad ones,
come back here first before replacing them, And make sure you take ESD precautions, or you will make a fixable unit, NON fixable.
If you don't know what ESD is, look it up, and ALWAYS keep yourself grounded right. Not just grounded, but correctly.