I am looking for some input into solving a (potential) problem that I have with
my Omni-C.
history:
I obtained this transceiver some months ago and it had been sitting in a box
for 28 years. Cosmetically immaculate but needed to have all the 100 nF bypass
capacitors replaced since these were all cracked. I next had a few
electrolytics go bad on me so replaced all the electrolytics. With that I made
a boo-boo - I replaced the keying capacitor of 33 uF that was on the PC board
with a value specified in the schematics of 4.7 uF. And then I build the TenTec
keyer. When the rig was left on CW then when powering up it would transmit a
dit before the whole rig ws powered up and this led to an early demise of the
finals. I have replaced those with MRF 454 and all is FB working except for SSB
TX.
I cannot find instructions for adjusting the TX mixer - what is in the circuit
diagram in the manual uses a ring mixer in a IC package and what I have is a
discrete diode ring mixer with two adjustable potentiometers.
Similarly the SSB exiter has an adjustable coil and I cannot find details on
adjustment of that either.
My problem is that after the rebuild the audio is distorted. I wonder if this
is due to some fault in the microphone or in the SSB exiter / TX mixer. CW
works like a charm and output is fine too. Even when transmitting on CW the
current nicely increases / decreases with the modulation, only it is garbled.
I do use this rig mainly on CW so it is not a problem but I do like to fix this
part. Where do I start?
Thanks in advance for your help, Marinus, ZL2ML
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