[Elecraft] RS-232 Problem

[Don Wilhelm]

Bob,
Since you have tried both the KIO2 (in the QRP cover) and the interface in
the KPA100, it would appear that the fault is likely with the cable.  I
suggest making up a cable like the one described in the KIO2 instruction
manual and try that out.

One other thought to try first - you said you did a master reset, did you
set the K2 secondary menu PORT  to ON?  I believe it defaults to OFF, and
the voltages you report inside the K2 are consistent with PORT being OFF.

73,
Don W3FPR

"Life is what is happening when you are making other plans"
-- Mike Cross

----- Original Message ----- 

Started getting prepared for the CQ WW WPX and discovered that my K-2 would
not communicate with my PC.  I have K-2 with KIO2 and a separate EC-2 with
KPA-100 & KAT-100 installed in it.  Last time I checked, a week or so ago,
everything worked.  No problems communicating with the separate KPA-100 &
KAT-100, so problem has to be with cable or RS-232 circuitry.

I've checked the following:

1. Changed ports on PC & control software.-------No Go
2. Checked connectors & measured continuity on cable-----Found shield
wire on K-2 end loose, resoldered----No Go
3. Moved KPA-100 back into K-2 & used RS-232 in KPA-100------No Go
4. Checked voltages on P-4 on Control Board with eight pin cable
disconnected.  Everything normal except for Pin 1 (TXD->1.64 V vs req 5.0) &
Pin 3 (RXD--->.06V vs req 5.0)
5. Checked  voltage around MCU RXD & TXD inputs & outputs.   5+V on pin
3 of RP7 & 0.06V on pin 4 of RP7, Also 0.06V on pin 26 (RXD of MCU)
6. Reset MCU & went through the woes of resetting filters and other
parameters.---Everything works except RS-232.