[Elecraft] RE: MORE CONCISE INFORMATION ON "HAS ANYONE SEEN THIS"

[James T. "Jim" Rogers]

Don, I know what you are talking about. I thought my reply had not reached
you. In my earlier message, down in the body I reported:

	"***Activating the KEYER will while DOT and DASH are held key down, the T8
and R8 voltages switch as would be be expected."

Under key down conditions, (I closed the dot circuit) the MCU supplied
appropriate signals to both switches. Once I went key up on DOTs both
switches (Q1 and Q2) went to OFF and remained so. Key down on DASH gets the
same result. I went back and forth several times to make sure I was not
fooling myself. Checks at the MCU pins 27, and 28 with DOT and DASH key up
were LOW. As a SYSTEM ANANLYST and a programmer of embedded processors in
the past (back when everything talked over a parallel bus)... after, and
only after, the myriad of tests I have made with a scope and DVM, I just
don't know where else to turn.

My first thought was SQUELCH, when that did not check out, I thought TUNE. I
really expected there to be a problem with the TUNE switch circuitry. No
such luck. I turned to the source of the signals to the switches, the MCU,
and searched for any other recognizable signals that could cause what I am
seeing on the switches. I was sure hoping someone would have a solution
because I hate to see problems with the MCU. Occasionally there is just a
bit that doesn't program, it just doesn't stick but there is usually a "read
back" verification. It is really difficult to relent and say MCU.

Building this kit after so many years away from process controllers etc. (I
program in several languages and finished my career as Imaging Coordinator
for the local county government) has revitalized me. I am having loads of
fun. Sure I wanted to be able to "hear" on 40 after reaching this stage in
the construction (I had to have Gary's help with the PLL check out) but the
chase is challenging and educational. The K2 is a wonderful kit and the
ELECRAFT gang, like yourself are what ham radio is really about as far as I
am concerned.

Thanks again Don

Don Wrote:

Well, Looking at the schematic, it is clear that you do not have the RX
signal at the gate of Q4 - we need to find out why and your problem should
be solved - note the K2 is NOT in transmit mode or the voltage at the gate
of Q3 would be +5 v.

Check the source of the RX signal - pin 28 of U6 (the microprocessor).  It
should be properly inserted into the socket (check to be certain it is not
bent under, or sticking outside the socket - in fact carefully check all the
pins on U6 to be safe.

After checking the pins, see if you have +5 volts at pin 28.  If you do,
check the path between U6 pin 28 and the gate of Q2 - follow the trace on
the PC board if you are able, making certain that everything in the path is
properly soldered.
OTOH, if you do not find +5 volts (or even +4 v or more) on pin 28 of U6
(and you have checked to be certain U6 is properly socketed at all pins),
then send a note to parts@elecraft.com explaining the situation and request
a new microprocessor.

Let me know what you find - note that I am having trouble posting to the
reflector for some strange reason - works sometimes and sometimes not
today - I do hope they get it fixed soon.