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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