Hello,
Currently trying to repair my monitor without a schematic. I have replaced all the large aluminum electrolytic capacitors, as well as the power mosfet for the backlight. Unfortunately this has not resolved the issue.
Here is a clip of my monitor turning on (sped up and trimmed, it took over 6 minutes to turn on):

When the problem first started to occur it took about 30 seconds to turn on, but has become worse over time. Does anybody on this forum have some ideas as to the particular circuitry that is failing? After the monitor has been turned on and is functioning correctly, I can turn it on and off again quickly without this issue occurring. However, if I leave it off or let it hibernate for longer, the issue comes back. To me, this strongly indicates a capacitor issue, but I'm not sure which cap could cause this, as I've replaced all the large caps on the main board.
Any suggestions would be appreciated!
Monitor: Samsung SyncMaster S22B350
*Quick Edit*
I've also load tested the power supply, virtually no voltage drop at rated load.