Got a replacement PSU (OCZ ZX Series 1250W '80 Plus Gold' Modular Power Supply) as the former was turned off incorrectly (not by me) which in turn affected the PSU and motherboard (Asus F1A75-V EVO AMD A75 Chipset (Socket FM1) DDR3 Motherboard)
Since installing the replacement PSU into the tower and reconnecting all cables as before, when switched on it clicks twice as the fans try to power on but fail.
Is there something else to check to get the PSU to power on properly, rather avoid having to return another PSU?
Sounds like they either didn't refurbish the unit completely, or there's other parts damaged. I think you can force the PSU to turn on by shorting the green PS_ON wire to a ground. This will make it power up if it can. If that works, then make sure the front panel connectors are set right.