Mike,
If you do not yet have a proper signal generator, try this - connect a
dummy load to the working K2, and set the power below 12 watts. On the
dead receiver, attach a short wire (not coax) as an antenna about 1 foot
long), and place it close enough to the working K2's dummy load to
produce the proper voltage at the bad K2 input (do not move the wire
after that, and do not change the powering K2's power level). Then
proceed with the receiver signal tracing as indicated in the manual.
You can use the TUNE button to set the working K2 to transmit a signal)
You should remove the KPA100 completely (Physically and electrically)
from the non-working K2 and use the lower panel BNC as the antenna input.
Again, let me know the first stage where the output is decidedly below
normal - stop and tell me where that point is and we can troubleshoot
that stage to the component level. I do not need/want any information
beyond that first failing point because it is not relevant until that
stage is repaired.
73,
Don W3FPR
On 9/8/2025 12:26 AM, Mike Furrey wrote:
Hi Mike and Don,
Thanks for the replies. We took out the 160 meter board and bypassed
it with clip leads.It has s/n 36XX (trying to remember as Jim took it
with him) We also pulled the KPA100 amp and used the BNC antenna jack
to connect to a dummy load to check power output ... around 10 to 12
watts, then to an antenna to listen for signals. I will talk with Jim
tomorrow and we will start developing a plan on the bench. Most of my
all of my test gear is at my TX home and we are currently in TN. I
have a scope here and a test probe and might have enough stuff to
build the crystal oscillator here ... once again plenty of stuff ...
not in TN. Hi.
Now that I just finished in the TNQP we will start a methodical look
at the front end.
We will keep y'all posted
Thanks es 73,
Mike WA5POK
On Sunday, September 7, 2025 at 04:33:37 PM EDT, W3FPR
<[email protected]> wrote:
Mike,
What is the serial number of that K2? If below 100, it is a Field Test
model and is slightly different that those above that SN.
I would not recommending "shotgunning" the problem, there is a
methodical way to go about it which will lead to the problem area
without guesswork.
The best way to troubleshoot a dead receive problem with the K2 is first
to remove the KPA100 completely, and then test the base K2 from the
lower panel BNC connector.
See the Troubleshooting section of the K2 manual (Appendix E). Since you
do not have a signal generator, you could build up the crystal
oscillator shown on page 9 of the Appendix. If you do not have a
'scope, you can use the RF probe also shown on page 9. It does not have
to be 'pretty' for this job, pushing the component leads though
cardboard and soldering them together will work fine for the frequencies
involved here.
The troubleshooting steps begin on the right column of page 10 and
continue thru the left column of page 12. With the proper input level,
you are looking to find the first stage that that has lower than
expected output.
Once you locate that stage, let me know and I can help you with
component by component checks to solve the problem. Dave Van Wallingan
W8FGU can also assist since he is the current /major repair person for
the K2 and other legacy gear that I used to repair.
73,
Don W3FPR
On 9/7/2025 1:07 PM, Mike Furrey via Elecraft wrote:
> At a hamfest a week ago there were two k2s for sale from an estate.
I bought one and a friend (not on here yet) bought the other. His
receiver is dead. The transmitter has full output (110 watts) on all
bands. The receiver ... AF gain works, side tone works, filters work,
and RF gain works. This can be heard in the change of the pitch/volume
of the noise emitted.
> ATTN and Preamp do not work/function. We see no codes. We made a
cursory disassembly and unseated and reseated all the boards. It has
the 160 meter option in, and we bypassed it. Unfortunately I sold my
old signal generator at the hamfest in anticipation of getting a more
up-to-date unit. Hmmm mabe use my old Model 59 GDO as a generator. We
are thinking relay ... haven't yet gone into it that far. One thing
that puzzles me is the RF gain control (R4). Where is it in the
circuit? I see it connected to J1. I see it coming off of P1 and that
is it where it ends!!?? I see R5, R6, R7, etc but I can't find where
R4 connects? I am thinking a relay somewhere in there? loose jumper or
plug I have overlooked? Maybe someone can throw me a bone as to a hint
as to where to look for the missing RF to the receiver.
> Many Thanks, Mike WA5POK
> ______________________________________________________________
>
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