[Elecraft] KIO2 stopped working - Wrong!

[Don Wilhelm]

John,

Forget the check on the MAX1406 - that is not involved in the path you are
attempting to reconcile.  The MAX1406 only does the CMOS level to RS-232
conversion for the computer interface out of the KPA100.  You problem is in
one of the non-RS-232 signal lines.

If you want to check the paths the quickest way, try this:
First connect the cable between the KPA100 and the KIO2.  Do not connect the
KIO2 cable to the K2 control board (you are going to be doing continuity
checks through the entire path).  Remove the ribbon cable from the KPA100
board so you can easily get to the KPA100 points.

Make continuity checks on the full path for the following signals - you
should find less than 5 ohms on each signal path:

8R   --- KIO2 AUX board pin 9 -- to KPA100 P1 pin 9
12CTRL --KIO2 AUX board pin 8 -- to KPA100 P1 pin 8
VRFDET --KIO2 AUX board pin 10 - to KPA100 P1 pin 10
ALC ---- KIO2 AUX board pin 7 -- to KPA100 P1 pin 7
AUXBUS - KIO2 AUX board pin 2 -- to KPA100 P1 pin 2
Ground - KIO2 AUX board pin 6 -- to KPA100 P1 pin 6
RS-232 signal Ground - KIO2 AUX board pin 5 -- to KPA100 P1 pin 5.

If all those paths show conductivity from end to end, the connections should
work unless something is shorted to an adjacent pin.

When you make these checks, you are testing the cable, the KPA100
connections and the KIO2 connections all at once - if any of them fail to
show continuity, you will have to find out which part of the 3 contain the
problem connection.

73,
Don W3FPR

> -----Original Message-----
>
> Don -
>
> Checked all the inductors and all showed continuity.
>
> The KPA100 works great when plugged into the K2.
>
> Tomorrow I'll check the voltages on the KPA100's U4, MAX1406.
> But, if the K2
> works via the ribbon cable, I may be barking up the wrong tree.
>
> As always, many thanks for the help.
>
> 73 de K1ESE
> John
>
>
> Don Wilhelm wrote:
> > John,
> >
> > Don't be so quick to conclude it is the KPA100 - the lines used
> for KPA100
> > control are different than the lines used for computer control.
>  Only 3 of
> > the pins in that connector are used for the serial port
> function, the rest
> > are used for K2 functions.  It pains me to hear the entire connecter
> > referred to as a 'serial port' - look at the name on the
> connector, it is
> > AUX I/O, and that means just what it says - an I/O connector
> for Auxiliary
> > functions - the RXD and TXD signals are the only ones used for computer
> > interfacing, and those are not used for KPA100 control when the
> KPA100 is
> > mounted externally.
> >
> > If the KPA100 works with the ribbon cable plugged into the K2, then most
> > everything is OK in the KPA100, but check the tiny inductors in both the
> > KPA100 (next to the DB9 connector) and on the KIO2 - on the
> KIO2, there is
> > one inductor on the AUX board.  Any of those inductors open will cause
> > problems with the KIO2 to KPA100 (or KAT100) interface.
> >
> > 73,
> > Don W3FPR
> >
>
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