Don,
Thanks. Morning < optimal coffee intake here.
This leaves the ribbon cable between KPA and K2, or U1 firmware.
Probably best to call Elecraft and get a replacement to verify this,
then.
Joe, KC0VKN
On Sep 26, 2007, at 10:21 AM, Don Wilhelm wrote:
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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