Don,
Yes the K2 is completely built & I was at alignment & test part 3 when I had
the low o/p power problem. I started the transmit
signal tracing procedure & did the receive testing to check the shared
circuits as instructed in the manual.
I'll carry on with the transmit signal tracing & see where I get to.
Thanks
73 Brian
G0WZX
----- Original Message -----
From: "Don Wilhelm" <d...@w3fpr.com>
To: "Brian Stevens" <br...@stevens7455.freeserve.co.uk>
Sent: Monday, November 04, 2013 1:03 PM
Subject: Re: [Elecraft] K2 #7379 troubleshooting
Brian,
Do you have the K2 completely built? or have you only built it up to the
point where you can receive 40 meters? I guess the point that you said
you had trouble adjusting the 40 meter BPF made me think the 10 MHz
oscillator might not work for you.
If you have it completely built, then the 10 MHz crystal will work. You
must select the 30 meter band.
However, because you have a transmit problem, you should use the transmit
signal tracing rather than receive - you will find the problem source more
easily, and the K2 itself provides the signals require for signal tracing.
Again, stop at the first point where the RF is substantially lower than
the expected value because you have found a failure point.
73,
Don W3FPR
On 11/4/2013 5:01 AM, Brian Stevens wrote:
Don,
I've had another think & the low readings I get at LPF,BPF & T-R sw o/p's
using the 10Mhz oscillator are with the VFO set so that I can hear the
oscillator signal, not at 40m. Should the signal still be attenuated
under these conditions?
The low power o/p problem occurred while trying to peak the 40m BPF
inductors L1/L2 with the VFO at 7.1Mhz.
73 Brian
G0WZX
----- Original Message ----- From: "Don Wilhelm" <w3...@embarqmail.com>
To: "Brian Stevens" <br...@stevens7455.freeserve.co.uk>;
<Elecraft@mailman.qth.net>
Sent: Sunday, November 03, 2013 9:15 PM
Subject: Re: [Elecraft] K2 #7379 troubleshooting
Brian,
If the test oscillator crystal is at 10 MHz, it *should* be very
attenuated by the 40 meter Low Pass Filter.
The K2 40 meter LPF cutoff is in the range of 8.5 MHz, so it cannot be
expected to pass a 10 MHz signal.
If you have a crystal in the 40 meter band, you could substitute it for
the 10 MHz crystal and try those measurements again.
If you do not have such a crystal, go forward in the Troubleshooting
procedure to Transmit Signal Tracing and try those steps. Do not skip
the oscillator checks - VFO and BFO that are in the Receiver Signal
Tracing part of the tests.
One thing about the Signal Tracing steps - work in the order listed, one
point depends on the one before it being OK.
Once you come to the first step where the output is significantly
(greater than 10%) lower than the Expected value, stop because you have
just found the output side of the failure point - it will be fruitless
to go on to other check points.
73,
Don W3FPR
On 11/3/2013 3:53 PM, Brian Stevens wrote:
Hi,
I've hit a snag during 40m tx alignment in being unable to peak L1/L2
to give more than about 500mW o/p with the power setting at 2W. I've
gone through the troubleshooting procedure & all checks out ok until I
get to the LPF,BPF & T-R switch section of the shared circuit testing.
Using the 10Mhz crystal oscillator in the manual with 0.14V at the
antenna i/p I get these readings:
LPF o/p @ W1 = 0.004V (expected 0.13V)
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