crackling static on #1 comm on xmit when eng running [solved]

[Niteridder64]

You guys have always helped me on other issues and I appreciate all the advice. This is a problem I thought we fixed but has come back. On our 1968 arrow the #1 comm, a kx 155, a loud crackling sound is heard while transmitting, the #2, a garmin, is fine. Sometimes it happens right away and other times a half hour into the flight and only with the eng running. There is no change in pitch when eng rpm is changed. I swapped radios w/ a friends, just yellow tagged unit, no help , swapped antennas still there. Tried the hand mic, different headset, shut off intercom, reracked radio, reracked audio control panel and sprayed down #1 push button switch in acp w/ electronic contact cleaner, no help. One thing not touched is the coax from the back of the rack to the antenna. Unfortunately the coax is fixed to the back of the rack, I cant screw in a temp cable to the antenna. That's all the info I have, any suggestions?

 

[EchoDelta]

 

[viper77]

 

[TEG916]

 

[paul_sherry]

 

[Niteridder64]

 

[EchoDelta]

 

[Tweety]

 

[FLYZONE]

 

[Niteridder64]