MSI KT4AV Power on Reset

Over the past few years I have built 3 PC's using the MSI KT4AV motherboard. I bought one of the boards second hand, and now I know why the guy was selling it. When the system is first powered up, although the fans all start up as normal, nothing else happens. If I leave it power up for 5 minutes and press the reset button, it boots up normally. Switching the power off and then back on after the warm up period also produces a successful boot. So I would guess that there is something wrong with the power-on-reset on the board, which needs a little time to warm up or charge up. Incidentally, I did swap it over with one of my other identical boards in another PC and the fault moved with the board.

I have checked over, visually, all the electrolytic capacitors on the board and cannot see any leaking or bulging, but I guess that is not exactly conclusive. Does anyone have any ideas how I might be able to find this fault?? Thanks for your time.