Testing PSU after storm

[Chrismk]

A colleague had a nearby lightning strike yesterday which wrecked his router (being replaced by Plusnet) but also his PC will not turn on.
The PSU is a Corsair VS650 and switching it on lights up the Reset and Power buttons on the Asus P6T Deluxe V2 motherboard. They are switching on and off quite rapidly, roughly 4 times a second.
I've used a test meter on the 20 pin supply cable but cannot get a reading off a red or yellow cable.
This would suggest the PSU is damaged but in which case, why are the motherboard button lights displaying?

 

[pastymuncher]

It does sound like it's had it and I would stop using it as it may damage other components. No surge protector I take it? Use it as a chance to upgrade from a awful psu to something decent.

 

[Mr Evil]

I've used a test meter on the 20 pin supply cable but cannot get a reading off a red or yellow cable.
This would suggest the PSU is damaged but in which case, why are the motherboard button lights displaying?

Red and yellow are 5V and 12V. The LEDs are probably powered by 5VSB (SB as in "stand by"), which is purple. 5VSB is separate from all the other voltages, and could well work even if everything else is broken.

 

[qbazdz]

You haven't got one of those PSU testers around?