Okay so I've done a bit more troubleshooting.
Started with measuring the potentiometers:
This is viewed from the front of the TV. The resistance shown is with the potentiometer turned that way, meaning left is counter-clockwise, right is clockwise and middle is... middle-ish, the highest value i measured on those two. Which was kind of strange.
All potentiometers seemed smooth, no sudden jumps or anything.
I've measured all the large, marked resistors, and they all have the correct values.
I've also measured the voltage out from Q901, main power regulator it seems. Voltage was +225V DC, so it seemed to be okay.
While measuring voltages, the large white 20W resistor (R322) got so hot it started smoking, so there is definitely something shorted or gone open circuit, meaning this resistor dissipates too much power. It's almost like a convection heater.
No fuses are broken either.
I'm suspecting that there is an issue in the main power area, seen here:
Or might there be something on the main board shorting the power supply?
It's such a pain trying to diagnose this without the schematic, and I'm quickly losing interest each time I try.
The model CTP3240 yields no results, and 79P-B8BF00 is the chassis number. I get some schematics from searching just 79P chassis, but it seems too different to be of use.
I've checked it thoroughly for cracked solder joints four times now, I see nothing.
Here's a high resolution image of the bottom of the board, if it's of any use:
https://i.imgur.com/XVnwNwG.jpeg
And one from the top:
https://i.imgur.com/0hIUEX3.jpeg
Next thing would probably be to check all the caps. There are some electrolytic caps marked "NP" which I'm guessing is non-polar?