Thanks. Morning < optimal coffee intake here.
This leaves the ribbon cable between KPA and K2, or U1 firmware.
> 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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