Wierd Red light on my PS3 .. is it a PSU fault indicator?

[Plasma]

Hi folks, I've asked in a few other places but got no reply so thought I'd ask here.

The other day I noticed a strange red light on my PS3 Slim that I've never seen before. The PS3 was turned off when I noticed it, it seems to turn on ok and I can use it, but I'd still like to know what it is. Its to the left of the drive tray, opposite side of the flat bit to the power button. I took a picture which can be seen here ..



When I Google all I get is results with people having the Red / YLOD. My PS3 s not actually that dusty, I think the flash makes it look worse than it is. I'm quite surprised that no one has ever seen this red light before, the PS3 has not been modified inside or anything and the warranty sticker is still intact underneath, although it is out of warrany.

Anyone any ideas? I'm assuming it may be a PSU fault as the light stays on even when its turned off, it does seem to come and go which would indicate an intermittent problem. Happy to buy a new PSU but would rather know that's what it is before I go spending money on it.

Plasma