Seasonic FANLESS 400w making crackle noise?

[darknite]

Ok so i've the subject title. Just recently there has been a electrical crackle sound when i first turn the system on. Lasts only a second. Its silent after that. Should I be worried? Plan to replace?

System runs the following
i5 4570T
Corsair H100
3x 4TB Seagate nas drives
1x Samsung EVO 250gb
Asus Z87 Gene
Intel raid card
Asus GTX960 Strix
3x 120mm case fans
2x 80mm pci slot fans

I just don't know what it could be. Blew out a tiny bit of dust, made no difference.

So yeah, should I worry? Should I plan to replace?

 

[darknite]

I get the noise when I turn on from case button.

Lead is fully inserted. Have tried 3 leads just in case was something silly.

 

[darknite]

Really? To cause a crackle from the psu? I'll test that tonight. Got a couple of spare switches. I did wonder if 400w is enough for all the kit. I was planning to add another 4Tb drive soon.