[TenTec] Century 21 Popping/snapping sound when keyed

[Paul]

I just got the old C21 out of the box and fired it up.  The rig has not 
been on the air in more than 10 years.  I worked through all the 
micro-phonics and dirty contact problems.  Receive and transmit are now 
clean and close to the original specs.

This question has probably been talked about previously on this group.  
So a little direction to its solution is appreciated.

When keying I hear a loud crack or thump sound from the speaker.  Any 
suggestions or direction to previous info will be appreciated.

Paul K.
WA0BAG