In the "old days" this could occur when a tube in the audio output developed
"microphonics." That is, a slight vibration of the tube would vibrate an
element inside the tube, causing the mechanical energy to be converted to
electrical energy. In solid state electronics, that's more rare, but still
possible. It can sometimes be traced to a marginal connector, a bad solder
joint or a cracked board, where the components still make contact, but
vibration varies the resistance of the connection.
Randy - K5MW
From: ic7000@... [mailto:ic7000@...] On Behalf Of
notcoldenough
Sent: Sunday, January 27, 2013 3:30 PM
To: ic7000@...
Subject: [IC-7000] I hear audio in the speaker when transmitting
I just purchased a used IC 7000. When I transmit, I hear my voice in the
speaker or headphones. It is a faint crackly reproduction of my voice. The
speaker monitor menu is set to "off", so in theory at least, there should be
no sound during transmitting.
The problem occurs in all bands, on both my antennas, and even while using
my dummy load. The only way I have been able to stop it is to reduce the
transmit power to 10%.
I cleaned the fuses, and even tried the power cable from my Kenwood. No
difference.
I removed the tuner from the antenna circuit. No change.
Added split core ferrites to all leads on the radio. no change.
One odd thing I noticed is that when I lightly touch the headphone plug, the
radio amplifies the sound of my touching the plug and outputs that sound
into the speaker. And yes, I verified that headphone was plugged into the
correct jack on the radio.
I have run out of things to check, so I plan on returning the used IC 7000
to the vendor. I am considering buying a new 7000, but I wanted to ask this
group if other users hear audio while transmitting.
Thanks in advance for your responses.
John
KC0UUT
