[ICOM] IC-765 Internal Audio Noise

[XJeep Guy]

Hello Kurt , thanks for the reply . Icom America emailed me first this morning ( talk about fast service ) !! The tech says this is a known issue in this rig and the audio emanates from the tuner and the corrective procedure is to re-align the tuner as put out in the service manual . So, I will do this on my next days off and see what those results are .  If that fails I'll take some of your suggestions and try those .

73

Jeff
VE7GMX

________________________________
From: icom-bounces at mailman.qth.net <icom-bounces at mailman.qth.net> on behalf of KD7JYK DM09 <kd7jyk at earthlink.net>
Sent: January 2, 2019 9:18 PM
To: ICOM Reflector
Subject: Re: [ICOM] IC-765 Internal Audio Noise

"Anyone run across this before?"

Yes, with many, many rigs across many decades, some intentional, some
not, depends on design, but both tube, and solid state. Sometimes a
radio physically generates noise with modulation. Sometimes one
component, sometimes several.

Depending on the rig, and cause (aside from monitor/side tone/RF
intrusion), changing settings, or microphones can change/eliminate it.
It may not be the exact issue, or cause in your instance, but in phone
rigs going back almost a century now, it's been a "thing", at times.
AM/SSB rigs the most susceptible, as it's associated with amplitude.

A quick easy test is battery power, short leads, into a load, starting
at lowest power output, away from the shack, and house, such as a park,
or field, away from anything else that may generate noise and be
confusing.  Bring a friend, have that person speak into the mic as far
away from the rig as physically possible, directly into the mic, cupping
a hand/hands over it to prevent you from hearing, increase power
until/if you hear the sound when you place an ear on the radio.  You may
have to listen to different areas of the radio.  The idea is to
completely isolate the radio and associated connected wires, and
feedline, first.  In the past I've also used a tone generator in an
electrically shielded, and mechanically dampened box with about 3" of
shielded wire to inject audio into an isolated rig, self contained, no
potential for stray RF, or microphonics.

Just some random trouble shooting ideas for that particular issue, with
other rigs.

""Name and callsign would be nice.""

I found this never had anything to do with the actual issue, or how to
address it...

Kurt

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