Powering up issue

Using my E6400's (2) Both upon initially pressing power button make a 1-2 buzz then dies out.
EOS loads normally. I hear this thru monitors or headphones even if vol is down.
Is it a problem w/ p/s?
Any ideas?
Sturoc
EOS loads normally. I hear this thru monitors or headphones even if vol is down.
Is it a problem w/ p/s?
Any ideas?
Sturoc