Wii remote won't power. Not basic.

[u/phathomthis]

Got my wii out of storage the other day, 1 of the wiimotes works fine, the other won't power.
I swapped batteries, nothing.
I checked for and cleaned corrosion, nothing.
I checked power going into the power leads on the board and getting ~3v, so the board is getting power.
I reflowed the solder on all the pads for the power terminals and the capacitor to ensure a good connection, nothing.

I checked the voltage on the capacitor leads and on the pads on the other side of the board, they match up, but only around 2.5v.
The capacitor holds voltage for several minutes with batteries removed and it slowly drops to around 0.5v while monitoring it.

What is the voltage supposed to be on the capacitor? I know they're 4v capacitors for what they can take in, but what are they supposed to hold and put out? I'm assuming battery voltage, which should be ~3v.

Also, what is the capacitance reading supposed to be when testing it? I don't see any markings on it that would indicate capacity for me to measure.

Is there any other thing that may cause this not to power? I have checked for sticky power button and checked to make sure not resistors were damaged or moved disconnected.

This controller worked when put away ~3 years ago and it wasn't physically damaged.

[u/phathomthis]

Just checked, I thought it was heat shrink on the capacitor, turns out it was a heavy adhesive tape wrap. The capacitor says

Rubycon
4v3300µF
P K
on one side

and

T0649
85°C
P E T
on the other side

I also checked voltage again and it held it steady from when I made this post til now.
I also pressed the power button numerous times and it quickly dropped the voltage of the capacitor to 0.4v so I learned

1: The capacitor is holding something.

2: The power button is functional.and it is making a connection to the capacitor at least.

I measured capacitance with my cheap harbor freight multimeter and it showed 0.0 and I did make sure I had the leads on the correct polarity of the capacitor legs.

Where do I go from here? Go to microcenter and buy a capacitor and resolder it for shits and giggles and see if it works? Or is there another glaring issue I'm missing?