Sharp LC70LE747 Flickering - darkening gradually to the right side

[SmartSarah]

I'm puzzled why it remains good as soon as it starts good.
Once running fine, I can tap on components and parts, it stays good.
Running bad, it appears to be immune to mechanical interference like tapping or touching band wires. No impact at all.
Ruling out connection issues is too soon, but not likely either.

[nomoresonys]

have a dumb little sceptre does similar, when it starts up, will run for as long as it's on, turn it off and won't start up again, have to mess with it, turn on and off with remote real fast and sometimes will turn on and do the same, won't tune any channels unless I use an external tuner, no response from remote or panel buttons when in bad state, thinking it must be bad memory, ie, eeprom, spi, nand, whatever is present.

[dskall]

Seems like a bad eemc or memory. If you have a programmer that can output print information during boot up. Maybe only way to solve this.

[SmartSarah]

I am on to something. If I apply 12v to the PNL power supply beforehand, the unit seems to start up correctly every time. I am going to use a scope to further investigate whether this voltage reaches the level quickly enough. If I do not find immediately why the power supply fails, I will install if necessary a separate 12v power supply for PNL.