Have you had any intermittent problems w/ it before?

I haven’t seen the inside of one yet, but I’m betting there’s either a bad switch or a dead op-amp causing your problem. If you just purchased it (assuming you bought it new), it’s still under warranty and you can contact EH to have it repaired.

When you say you’ve only just got it do you mean today? if so take it straight back to where you got it, like you would anything else you buy that’s defective.

lol, have you checked your cables and things like that? sometimes the problem is something silly you might not have even considered.