VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 01-10-2019, 04:11 PM
Clparker23 Clparker23 is offline
 
Join Date: Jan 2019
Location: Texas
Posts: 3
Default GMA 345 no radio transmit

Bought from spruce, had them make a harness, wired to brand new GTR 225, I hear myself, Radio indicates coming in but nothing comes through GMA 345. Bluetooth works, mics work, mic key works. No indications when diagnostics are run. Thanks for help in advance.
Reply With Quote
  #2  
Old 01-10-2019, 07:01 PM
g3xpert's Avatar
g3xpert g3xpert is offline
 
Join Date: Sep 2010
Location: Olathe, KS
Posts: 2,310
Post

Quote:
Originally Posted by Clparker23 View Post
Bought from spruce, had them make a harness, wired to brand new GTR 225, I hear myself, Radio indicates coming in but nothing comes through GMA 345. Bluetooth works, mics work, mic key works. No indications when diagnostics are run. Thanks for help in advance.
Hello CLparker23,

Welcome to VAF!

It would probably be best to contact Aircraft Spruce or Garmin directly, but we are happy to try to help.

As you are probably aware, there are 4 dedicated knobs on the GMA 345 that control music and intercom volume for the pilot/copilot. These have no effect on the volume of the COM1 or COM2 radio.



The radio volume is controlled at each radio.
  • Does increasing the volume on the GTR 225 allow you to hear the radio?
  • If you break squelch on the GTR 225, you should be able to hear yourself adjusting the radio volume even when not receiving a transmission.
  • Have you tried enabling both COM1 audio and COM2 audio in case the radio is connected to the other position?
  • Have you made sure that the GTR 225 internal intercom is disabled?

If you have already considered and tried the above steps, then there is probably a wiring problem in your harness that is not allowing the COM audio signal to reach the audio panel.

Thanks,
Steve
__________________
Garmin G3X Support
g3xpert@garmin.com
1-866-854-8433 - 7 to 7 Central Time M to F
Please email us for support instead of using Private Messaging due to the limitations of the latter.
Reply With Quote
  #3  
Old 01-11-2019, 06:43 AM
Clparker23 Clparker23 is offline
 
Join Date: Jan 2019
Location: Texas
Posts: 3
Default

Thanks Steve,
I have tried both comm 1 (GTR 225) and comm 2 (kx170). Neither coming through.

I read about disabling internal intercom on GTR 225 last night. Im headed that way to try that.

I have reached out to spruce and Garmin and waiting for a reply. But just got to the point to reach out to the entire community.

The kx170 is wired with a speaker load. However the lo wires from the GMA 345 to the kx170 are folded over and not connected at all...should they be grounded to the kx170 chassis?

Thanks again!
Reply With Quote
  #4  
Old 01-11-2019, 12:44 PM
g3xpert's Avatar
g3xpert g3xpert is offline
 
Join Date: Sep 2010
Location: Olathe, KS
Posts: 2,310
Post

Quote:
Originally Posted by Clparker23 View Post
Thanks Steve,
I have tried both comm 1 (GTR 225) and comm 2 (kx170). Neither coming through.

I read about disabling internal intercom on GTR 225 last night. Im headed that way to try that.

I have reached out to spruce and Garmin and waiting for a reply. But just got to the point to reach out to the entire community.

The kx170 is wired with a speaker load. However the lo wires from the GMA 345 to the kx170 are folded over and not connected at all...should they be grounded to the kx170 chassis?

Thanks again!
Hello Clparker23,

Not sure what a KX 170 is, but we found a 1976 installation manual for a KX 170A/B.

We see what you mean about the KX 170A/B only having a COM Audio Hi output, and no COM Audio Lo output.

We recommend using the same shielded pair audio wiring shown in the GMA 345 installation manual, with the shield braid terminated only at the GMA backshell. Since the KX doesn't have a dedicated COM Audio Lo pin, you can connect that wire (coming out of the shielded pair) to the KX chassis.

The KX 170A/B has a dedicated 500 ohm COM Audio Hi, so the COM audio should not be provided via a "speaker load".

If you want to email (see below) us the wiring diagrams for your harness, we can provide further review.

Thanks,
Steve
__________________
Garmin G3X Support
g3xpert@garmin.com
1-866-854-8433 - 7 to 7 Central Time M to F
Please email us for support instead of using Private Messaging due to the limitations of the latter.
Reply With Quote
  #5  
Old 01-16-2019, 04:40 PM
Clparker23 Clparker23 is offline
 
Join Date: Jan 2019
Location: Texas
Posts: 3
Default

Steve,
I pulled everything out and looked it over, I removed the kx170 from the audio panel to focus on 1 radio. I have the GMA 345 and GTR 225 only hooked up. I can only hear an extremely faint RX when the GMA is not turned on. When its turned on, absolutely nothing.
Thanks,
Clayton
Reply With Quote
  #6  
Old 01-16-2019, 06:55 PM
g3xpert's Avatar
g3xpert g3xpert is offline
 
Join Date: Sep 2010
Location: Olathe, KS
Posts: 2,310
Post

Quote:
Originally Posted by Clparker23 View Post
Steve,
I pulled everything out and looked it over, I removed the kx170 from the audio panel to focus on 1 radio. I have the GMA 345 and GTR 225 only hooked up. I can only hear an extremely faint RX when the GMA is not turned on. When its turned on, absolutely nothing.
Thanks,
Clayton
Hello Clayton,

There are only 2 wires that bring COM audio from the GTR 225 to the GMA 345 COM1 audio input.

I would start by confirming good connections between those two sets of pins and making sure neither wire is shorted to ground.

Please email us at G3Xpert@garmin.com if you need our assistance in confirming the correct pins on each unit.

Thanks,
Steve
__________________
Garmin G3X Support
g3xpert@garmin.com
1-866-854-8433 - 7 to 7 Central Time M to F
Please email us for support instead of using Private Messaging due to the limitations of the latter.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 11:11 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.