If it is just a dead PSU, then it should be dead caps. But in seeing the video I notice that there are 2 regulators and a fuse. The fuse can blow early on but I doubt the regulators would go. When you recap the PSU, test it with a multimeter. It should be within 1 volt and .5 amps of its rated output. I prefer to use an analog meter for this, as if there is flutter in the circuit, you can see the needle shake. The needle should be rock solid still. If there is a flutter, it could be an aging regulator or the outside environment (like your refrigerator turning on and causing a power dip in the house), you need to figure it out.
There are two Pots (Potentiometers, aka. variable resistors) on the PSU Daughter Board. One adjusts voltage, the other adjusts the amps. But, in adjusting one, you also affect the other, so you need to get it in a balance of the two as close or on rated output as possible. Use plastic tools for this. And if possible, use two meters at the same time to measure each output separately.
I know you can do this. Compared to a logic board, it should be easy. Easier than replacing the caps on a LC PSU like you and I did in the past.
Good Luck.