[TenTec] Why does OMNI V click???

[OTAKEBI at aol.com]

My OMNI V seems to have developed a click that is about half as load as the 
PTT relay and seems to come out of the rear right hand side of the rig near the 
Ant. input.
The click only takes place when I first turn the rig on after it has been off 
for a few hours.
It takes place the first time I hit the PTT on the mike and about a second 
after I hear the relay click to transmit. When I let up on the mike key I hear 
the PTT relay go back to receive. No send click
The click does not happen again. Only one time.
Anyone have any idea what this noise is or what could be making it?
Dan N4VET