[Elecraft] Help!! Complete K2 Catastrophe

[Dauer, Edward]

Tegsting out the newly built K2 tonight.  Everything was working just 
fine.  Then tried the direct frequency entry, at 10000 to see if WWV came 
in.  Everything went dark.   All I hear is a rhythmic popping noise in the 
speaker.  Shut it off and on.  No change.  Unplugged power supply.  No 
change.  Tried to reset to factory defaults.  No change.  With the power 
on it just sits there, dark, making a brief popping noise about once a 
second.  No switch or combination of switches changes anything.

What did I do?  More to the point, how do I undo it?  Any ideas will be 
greatly appreciated.

Ted, KN1CBR