Piper J3
Well Known Member
We have a four year old RV-12 built by Synergy in Eugene, OR. Airplane has dual HDX, autopilot, ADSB-in/out, Lightspeed Zulu3 headset. No problems until a few months ago when Comm radio started slight squeal when transmitting. Problem has gotten progressively worse and so we are attempting to fix. Squeal was noticed in headset as well as by receiving aircraft.
So, we removed the radio and sprayed contact cleaner on antenna connections and 25-pin D-Sub connector on both radio and tray. Re-inserted radio and now squeal is constant. We tried a known-good GTR200 in our airplane and same squeal and also tried our radio in another airplane and it was good there, so radio is not the problem.
Headphone jackets look to be tight and squeal is same if headset is plugged into either pilot or co-pilot side. Also tried another known-good Zulu3 headset and same squeal. Both PTT switches show lighted Tx on face of radio, so both PTT switches are OK.
We examined the female 25-pin D-Sub thinking maybe a socket pin got pushed back in the housing, but it looks OK. The coax antenna connector on the back of the tray seems to “float” and we think that is for alignment to the radio. BNC connector on back of tray looks good and center pin is straight. BNC is tight. BNC connector on belly antenna looks good.
Need help with suggestions as to what would cause squeal that is external to the radio itself.
As always, thanks in advance...
So, we removed the radio and sprayed contact cleaner on antenna connections and 25-pin D-Sub connector on both radio and tray. Re-inserted radio and now squeal is constant. We tried a known-good GTR200 in our airplane and same squeal and also tried our radio in another airplane and it was good there, so radio is not the problem.
Headphone jackets look to be tight and squeal is same if headset is plugged into either pilot or co-pilot side. Also tried another known-good Zulu3 headset and same squeal. Both PTT switches show lighted Tx on face of radio, so both PTT switches are OK.
We examined the female 25-pin D-Sub thinking maybe a socket pin got pushed back in the housing, but it looks OK. The coax antenna connector on the back of the tray seems to “float” and we think that is for alignment to the radio. BNC connector on back of tray looks good and center pin is straight. BNC is tight. BNC connector on belly antenna looks good.
Need help with suggestions as to what would cause squeal that is external to the radio itself.
As always, thanks in advance...