[Elecraft] K3 RTTY PROBLEM

[Bert via Elecraft]

I tried to get on the OK DX RTTY contest this weekend using my K3. I used  
N1MM+ with MMTTY and configured MMTTY as usual. Hit the TX button in MMTTY, 
the  K3 went into transmit mode with no output!
I'm using FW version 5.01 on the K3. 
I eventually resolved the problem, but don't know the reason for it! What  
happened is this: in MMTTY Config, I set the Mark (and HAM Default) 
frequency at  2125 Hz, as I've always done. No r.f. output from the K3 with the PC 
(and  interface) putting out the RTTY signal...
The solution was to set the Mark (and HAM default) frequency to 915 Hz (170 
 Hz shift, of course!). That worked! 
I swear I NEVER touched the PITCH button, never mind that I had never  
changed the Mark frequency there...BUT, there it was, big as life, 915-170! Did  
this parameter change on its own from 2125 to 915, or did this change take 
place  with FW updating? 
"Curioser and curiouser..." as Alice would say!
 
73, Bert, N4CW