Hi All
Email support from Elecraft is very slow since about the beginning of 2019.
May be due to a system change. Before it was really good!
I own equipment ( 3xK3S, 3xP3, 1xKPA500 etc.)
Therefore I turn to this group to be able to fix my K3S TX by myself.
Sending the unit for repair to Italy is no option because of crazy VAT there
( HB9 no EU).
How is your equipment operating ?
K3S # 10490 factory assembled is now not TX working at all, based on IMD 3
(24dB, basically on all bands) and too low output problems.
I try to troubleshoot/repair it and need further supporting technical info.
I took out the 100W PA , replaced it with an older K3 module I had -> no
improvement.
If only running the 10W module the IMD is bad and I have only limited
output.
Analyzing the output from XVERT out BNC the signal is clean and about
1mW/50Ohm.
1) It would be helpful among others to receive info on the DC voltages (
Bias etc.) in the 10 and 100W module.
In order to analyze the bias voltage/ current technical info is needed.
2) Is there any good way to check the QSK diodes?
I want to make sure the diodes are working well. Should I replace them?
I did measure it at XVTR OUT BNC. Output level about -1dBm to 0dBm into 50
ohms.
Turning on the 2 Tone (Tech MD on ) and watching on the spectrum analyzer HP
8591E ( all functions auto/ cal. ok) with 10 dB 50 Ohm external attenuator
shows a
signal (2 Tone) which looks very clean down to at least 45 dB to almost
50dB on each side. Basically there is no difference on 160 or 80m or 40 .
I can however not see expected side products (IMD3) here. May be the signal
is just very good here ( Span e.g. 10kHz, sweep 10 sec) .
In all measurements the LPA was set to about 11 watts connected to 50 Ohm DL
anyway-probably disabled by SW . After resetting KXV3B to normal IMD3 at PL
output -no 100W engaged - very bad again with about 10dB worst case.
My conclusion there is again a problem in the new LPA (10W).
What is your analysis?
When I happily replaced the 10W/100W module last year (based on returned old
once later , nice service!) all looked fine and then back to same problem.
Thanks for any hints from the group .
Cu, vy 73 Andy
HB9CVQ, DK2VQ, AK4IG
<
https://www.qrz.com/db/HB9CVQ>
https://www.qrz.com/db/HB9CVQ
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