[Elecraft] K3 choppy CW

[Robert Mccormack]

At ZM1A (multi-two) during the ARRL DX CW contest we received some reports of "choppy" CW when CT was keying via the 'Key' socket.
Monitoring the signal with a K2 (dummy load in antenna socket) confirmed the reports.   CW sent using the paddle was normal.
Both 'station one' K3 and 'station two' K3 had the same problem - substituting a spare K3 made no difference.   BTW, it's not RF getting into the computer - the keying is just as bad at 5 watts out.

We continued operating, using the K3 memories for CQing and the exchange - luckily it wasn't a serial number.<G>

I don't know when this "choppy" keying problem started because the K3s are only keyed by CT during contests, but today we tried a spare 746Pro which eliminated the problem.

So the problem is specific to our K3s, all of which had  MCU 2.67 installed plus the 'CW rise time' and RS-232 RF immunity mods in early February...

Anyone else had this problem?

73, 
Ken ZL1AIH (ZM1A in contests)