[Elecraft] K3 no TX, no RX, and solved

[Arie Kleingeld PA3A]

Just for sharing.

Case:
K3 #1255 (loaded)
Has all mods during the years and upgrades to K3(s) except for USB port

Problem: no TX and no RX (not on main, not on sub)

Analysis:
1. Connecting a panadapter on the IF out: IF signal of main RX is there 
and and signals are where they should be, so VCO of main RX (as first 
oscillator) is working all right
2. The two pre-amps, attenuator, and antenna switches working fine 
(checked on panadapter)
3. RF gain to minimum moves S-meter to max on Main- and Sub-RX (normal)
4. All RX DSP functions seem to work on the little noise that is audible
5. Audio spectrum analyser connected at audio output shows that IF 
filters do not influence the audio bandwidth, only the DSP does. 
(fiddled with the filtersettings in the K3 utility)

Conclusion:
There's a hick-up between the 8.2MHz IF and the entrance to the DSP, 
seems like 2nd IF of 15kHz is down. No mixing signal form 8.2MHz to 
15kHz? That one sits on the KREF3, where all those TMP-cables come together.


Checking the reflector...
Found this line: 'TMP-cables are a class by itself' , and indeed it is 
so.  :-)

Repair: Refitting all TMP-cables

Result: K3 is playing as normal again and PA3A is a happy man.
(By the way, this is not the first time in the life of #1255 that its 
TMP-cables needed a little push.)


Cheers and 73 to all,

Arie Kleingeld PA3A