[Elecraft] speaker clicking on K1

[km5ps]

I have just bought a used K1 off of ebay.  I have noticed that when I 
send code I hear a loud clicking noise other than the cw sidetone coming 
out of speaker.  Is this normal for the K1.  From video's off of 
Youtube, I don't notice that on other K1's.  Just curious if this the 
way it is with the K1.  If not what would be some things to check for or 
could it be a bad speaker?

TIA
John
km5ps   new owner of K1 #0930