Diagnose failure in LED driver
It could be a capacitor or other component in the driver, but it could be also a bad LED or a bad solder joint on the LED PCB.

You can try looking at the LED PCB:


If all the LEDs are in series, then one dead LED will open the whole circuit and all LEDs will turn off. You can't know whether the fault is in the driver or in the PCB. Thermal expansion and cooling can make a bad contact intermittent and it can cause blinking.
If they are wired in several series/parallel strings, then one dead LED will only open one series string, and that wouldn't make the whole lamp blink, only part of it. In this case, the fault is most likely in the driver.


In case 1, you need to find out if the fault is in the driver or in the LEDs. Since you already opened the light, simply power it up and probe the wires going to the LEDs with a multimeter. If you got a stable voltage but no light, blame the LEDs. If you got no voltage or unstable voltage, blame the driver, unless the LED board is shorted, but that would be unlikely.

You can estimate voltage by counting LEDs in series. Each white LED is about 3-3.5V.

You can also replace the driver with one from a working lamp to narrow it down.

If the driver is gone, most likely cause is the big capacitor, but it only takes a few minutes to perform these checks.