After dis/reconnecting my HP Pavilion T490 from the mains, the power supply makes a rapid ticking sound (several times a second) and the light on the back of the power supply flashes.
It happened a few months back too, after a vacation, but then, after a few tries, the PSU kicked in. After that time, I disconnected the power several times bu pulling the cord out of the socket. This time, and before going on vacation, I first switched of the Belkin Surgemaster before pulling the cords out of the sockets.
To resolve the issue, I tried disconnecting wires, PCI cards, etc, and the things that seems to do the trick is disconnecting the ATX plug from the motherboard. But that still leaves me clueless as to what is the cause. The motherboard or the PSU. From what I've read, it is either the overvoltage protection kicking in or a capacitator that fails to charge fully. I personally suspect the later, but not sure wheter it would be a capacitator on the motherboard or in the PSU.
Last time I checked with Speedfan, voltages, rpm, temps were all ok. Computer was stable, connected to a Belkin Surgemaster Gold,
I've googled quite a lot, and found people with similiar issues, but never an sollution :-/