Crap, rigged up my Mamba 25 this afternoon and it did the same non-arming thing, it was the motor that kept it from going through. I took the old nuked one back to the store and returned it for a brand new one but still the same KMS 2814/08, I think I'll just run 3s for now with the Mamba 25 until I get the Mamba Max back......hopefully they'll tell me it's still fine too.