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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