Hi Charlie,
I had a similar issue with my K3s (real one - not upgraded K3): 30 dB
attenuation or so on all received bands. I used a RF generator set to
-10 dBm (100 micro Watt) connected to the RF input (with microphone
disconnected to avoid chance transmitting into the generator). And
traced the signal through the circuits, guided by the available
schematic, with a high impedance (100 kOhms) RF voltmeter. Finally
spotted the cause: a dead PIN diode. Replaced the guy and... had a
cigar! Don't remember the designator, but can retrieve it for you if
needed (however K3 and K3s may be different, and anyway another PIN
diode may also be involved).
You didn't tell us if you estimate having sufficient electronic skills
and/or experience to dig into the rig. And say if you own the described
equipment; if not you may buy a low cost used generator from the bay or
a small synthesizer from Amaz or Ali , and make a home-built sniffer
probe with a Shottky diode + capacitor connected to a low range
voltmeter, preferably electronic, to track the signal. A min 20-30 MHz
oscilloscope may also be used.
HTH,
Christian F1GWR
On 1/27/2025 1:31 PM, n0...@juno.com wrote:
Hi Gents,
My K3 has a problem and it's intermittent. Maybe someone
has had the same issue and knows of a possible remedy.
Here are the symptoms:
1. Switch on radio. Nothing being received except I can
hear the neighbor's electric fencer and I can hear *some* "normal"
powerline noise. NO signals heard on the AM Broadcast Band
which is very unusual. It's like the signals that need to be
processed/demodulated aren't.
2. Radio doesn't transmit when the no receive problem occurs.
3. Turn off radio...
4. Turn radio on and everything is normal, sometimes.
5. It doesn't seem to matter if the radio is warmed up or not.
6. Voltage to the radio is okay at all times.
7. Audio out is okay at all times., i.e it isn't totally dead.
8. Gently "banging" on the radio doesn't help...connections all
okay in back of the radio.
9. I can hear some noise increase/decrease when the RX pre-amp
is switched in/out.
10. The attached P3 sometimes won't update either when the freq
is changed...recycle the K3's power switch and then all okay
with the P3....might be a separate issue.
11. Other bands have the same "no receive" problem.
So...any ideas to help me zero-in on something to check first after
I open the covers?
Thanks,
Charlie, N0TT
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
