[Elecraft] Re: Elecraft Digest, Vol 28, Issue 5

[PDouglas12 at aol.com]

Hi Folks,
 
I read this list on a reasonably regular basis, and I don't remember seeing  
this problem.  I have a old K2 (serial number 191) with SSB, KI02, and the  
mod for bandwidth improvement on PSK 31.  Along the way, a firmware upgrade  was 
installed.  No, I'm not selling it!
 
The problem is with the KI02, the serial port adapter.  It worked fine  until 
a few weeks ago. Today, as part of the troubleshooting project,  I finally 
got around to trying it with a second computer, and  neither computer can read 
the K2.  No, it's not a program problem, as  I tried the usual stuff, including 
HRD, all of which worked previously.   And yes, the cable has been opened and 
checked at both ends.  No  loose connections.  Yes, too, the "Port" is "on" 
in the menu.  This  tells me the K2 can see it.  However, when I tried to send 
and receive data  using Hyperterminal, a weird thing happened.  Sending 
"SW01;" turns off the  port!  According to my manual, this is supposed to change 
bands, not turn  the port off!  This is repeatable, and happens with both 
computers.   Is this evidence of a damaged IC on the KI02?  Note, I have a load, 
clear  oscillator signal at 16.29.
 
Suggestions?   By the way, I have a vacuum desoldering machine,  so removal 
and replacement of defective through-hole ICs is trivial.  Is  that what I 
need?  A new chip?  The schematic shows that the I/O is  not buffered or 
protected, so I am figuring that's what needs to be done?   What say engineers?
 
72,
 
Preston Douglas WJ2V