[Elecraft] Info 080 and KPA100

[Don Wilhelm]

Joe,

No need to 'start with U4' since you have 5 volts at U1 pin 1.  Check my 
conditional statements - U4 and the others were *only* to be 
investigated *if* there was a low voltage at U1 pin 1 - 4.9 volts is 
well within the tolerance for the 5 volt regulator output, so the 5 volt 
rail is fine.  Your problem is either with a break in the AUXBUS signal 
line back to the K2 (do continuity checks) *or* a bad firmware chip in 
the KPA100.

73,
Don W3FPR

Joe Hetrick wrote:
> Thanks Don (and Ken),
>
> On Sep 26, 2007, at 9:13 AM, Don Wilhelm wrote:
>
>> 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.
>
> I started this process before I left for work.  It was pointed out to 
> me that I hadn't dug hard enough in the archives; tried again and 
> found someone talking about problems with U6 causing this sort of 
> behavior.  As an aside, I note one relay clacking when firing up the 
> KPA.  There is a twitch of life.
>
> What I noted is:
>
> KPA U1 P1 has 4.9V
> U6 pins 7 and 8 have 4.9V
>
> I also walked down the MAX to see what I could find, and it has 13.8V 
> on P1.  I didn't bring the list with me, so I'm working from memory.
>
> I can wander down the rest of the AUXBUS chain as I go.  I shall start 
> with U4 as you suggest below.
>
> 73,
>
> Joe, KC0VKN
>
>>
>> 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?
>>>
>
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