No need to 'start with U4' since you have 5 volts at U1 pin 1. Check my
rail is fine. Your problem is either with a break in the AUXBUS signal
> 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?
>>>
>
> _______________________________________________
> Elecraft mailing list
> Post to:
[hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>
http://mailman.qth.net/mailman/listinfo/elecraft
> Help:
http://mailman.qth.net/subscribers.htm> Elecraft web page:
http://www.elecraft.com>
>
Subscriber Info (Addr. Change, sub, unsub etc.):