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SL40 problems

funflying

Well Known Member
In January my SL40 went back to Garmin for service because my local avionics shop said it was over modulating. Garmin replaced the circuit board. I had an SWR check done and they said the radio coax checked good and antenna was good. Now the test was to fly and operate the radio.
Yesterday ground and tower didn’t report any problems hearing my transmissions but I was getting a feedback through my headset (Bose A20). Going into a unicomm airport I continued to hear the feedback on transmissions.
I found a post about the internal adjustments of the SL40 and did those with no change in the feedback noise.
Today I spoke to the Garmin rep and he said I need to confirm the ground from the audio plug shield is good. If this ground is good I may need to send the radio back. I left a phone message at Vans but Keith from Stein spent some time with me talking about where this audio ground from the shielded wire from the headset is actually grounded.
It involves accessing behind the panel to get to the back of the radio tray. I’m looking for other things I might check while in there or other grounds that might cause this transmit feedback in the headset. Thanks
 
Tray came out, continuity checked from the radio to the control modular, plug pins checked and cleaned. Reassembled and two ground runs completed with good contacts to tower, and no feedback during transmission.

Time to fly and check again.
 
I had an issue where when I keyed the mike on pilots side, I got a feed back noise, nothing when I keyed the RH mike...turned out to be my intercom volume was maxed out for the pilot side....
 
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