[Elecraft] Info 080 and KPA100

[Don Wilhelm]

Joe,

The info 080 message means that the K2 cannot communicate with some 
other processor that is attached to the auxbus - in your case, the KPA100.

I would first check to see if there is 5 volts present at pin 1 of 
KPA100 U1.  If you have 5 volts there, then the problem can be found 
somewhere on the AUXBUS signal itself between KPA100 U1 pin 28 and K2 
Control Board U6 pin 40 - this path involves the ribbon cable and its 
connectors, use the schematic to follow the path and check each point.  
It may be that the KPA100 firmware chip has become damaged, and the 
easiest way to determine that is to replace it.

If you do not have 5 volts at U1 pin 1, then there is a problem with the 
5 volt rail in the KPA100.  If you find zero volts, the regulator is 
likely bad.  OTOH, if you have a small voltage instead of 5 volts, the 
usual cause is that something is loading down the regulator output - 
remove U1 and check for voltage again - if that does not restore the 5 
volt output, then one of the other chips is at fault and you will have 
to remove them one at a time to determine which one is bad - the suspect 
list (from most likely to least) is U4, U6 and U5.  The KPA100 will work 
without U4 installed (but will not have computer control functions 
available), but if U5 or U6 are removed, the power control circuits will 
not work and the KPA100 will develop full power output.  If you realize 
that, you should know that you  can still test the KPA100 to see if the 
info080 is gone, but do not expect power control until you replace U5 
and U6.

73,
Don W3FPR



Joe Hetrick wrote:
> Greetings folks,
>
>     If I may interrupt the K3 threads for just a moment...
>
> My K2 SN 4912 developed a fault sometime between last evening and this 
> evening!  Upon jumping to the shack to
> have a few relaxing QSO's before bed I was greeted by an INFO 080.  I 
> figured I'd start by checking pins of RFU1 as in the
> manual and pulled the KPA.  I fired it up without the KPA, and, 
> problem disappears.
>
> Casual inspection of the KPA shows no fault, searching the list turns 
> up no clues, and finally the KPA manual refers INFO 080 back to the K2 
> manual.
>
> If I had to guess, I'd say auxbus short.
>
> With only the KPA connected (nothing external to the AUX RS232) fault 
> remains.  Where should I start digging in the KPA?
>