Hey all,
I'm having issues with a new install of a gns430aw.
It was just installed as com/nav 1 and replaced a kx165. The issue is there is very low audio output from the 430 on com and nav. With the volume turned all the way up the audio is barley loud enough to hear. You can open the squelch on the volume knob and get hardly any audio. The installing shop installed 15k ohms of resistors on the audio high output from the 430 to the audio panel and it increased the volume slightly. The issue exists on both the overhead speaker as well as the headset jacks. I had the 430w bench tested before the install and it had excellent audio output on the bench so I feel confident the 430 is not the issue. The plane (C172N 24v) also has an Intervox NAT intercom system (I believe it to be an AA80-001), kma 24 audio panel. The audio panel was swapped with another kma 24 and the issue remained. Com 2 is the kx165 that used to be com 1 and the audio output from it is loud and clear. The installing shop told me nothing was changed on the intercom during the install.
It seems to me that if the 500 ohm high needs 15k ohms to hear anything then there is an issue with the impedance, but I am at a loss as to why. It is grounded at the ground lug on the kma 24. The shop is sure that the connections are good and the pinout is correct. What the heck is going on!?!
Also, I found this in the maintenance manual and I am curious if any one can explain the "microphone intercom" part? "Comm radio audio output will supply 100 mW to a 500 ohm load. This audio is the summation of the receiver, microphone intercom and sidetone."
Any help would be greatly appreciated.
I'm having issues with a new install of a gns430aw.
It was just installed as com/nav 1 and replaced a kx165. The issue is there is very low audio output from the 430 on com and nav. With the volume turned all the way up the audio is barley loud enough to hear. You can open the squelch on the volume knob and get hardly any audio. The installing shop installed 15k ohms of resistors on the audio high output from the 430 to the audio panel and it increased the volume slightly. The issue exists on both the overhead speaker as well as the headset jacks. I had the 430w bench tested before the install and it had excellent audio output on the bench so I feel confident the 430 is not the issue. The plane (C172N 24v) also has an Intervox NAT intercom system (I believe it to be an AA80-001), kma 24 audio panel. The audio panel was swapped with another kma 24 and the issue remained. Com 2 is the kx165 that used to be com 1 and the audio output from it is loud and clear. The installing shop told me nothing was changed on the intercom during the install.
It seems to me that if the 500 ohm high needs 15k ohms to hear anything then there is an issue with the impedance, but I am at a loss as to why. It is grounded at the ground lug on the kma 24. The shop is sure that the connections are good and the pinout is correct. What the heck is going on!?!
Also, I found this in the maintenance manual and I am curious if any one can explain the "microphone intercom" part? "Comm radio audio output will supply 100 mW to a 500 ohm load. This audio is the summation of the receiver, microphone intercom and sidetone."
Any help would be greatly appreciated.
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