Com 1 not transmitting on my GMA 1347

[PJB]

I have a 2006 Mooney Ovation 3 with 2 non-Waas G1000’s and a GMA 1347 audio panel. I just purchased this aircraft and it has been sitting for 2 1/2 years in an enclosed hangar. 
The trouble I am having is that Com 1 is not transmitting. I can receive on Com 1.  The TX light lights up and I get a side tone. Com 2 operates normally in transmit and receive. 
Can anyone help me troubleshoot this problem? If there might be a loose wire at the antenna, which antenna is Com 1 connected to - the forward or aft antenna?

Thank you,

Paula B

[carusoam]

Welcome aboard Paula!

Sounds like a wire isn’t working the way it should…

What part of the Mooney World are you in?

Best regards,

-a-

[carusoam]

Oddly,

Big G doesn’t share their install manuals….

But, I found this one… it may be close to what you have?

https://static.garmin.com/pumac/GMA1347DAudioPanel_InstallationManual.pdf

Kind of gives a good hint of what the wiring diagrams look like….

Best regards,

-a-

[PJB]

Thanks! It is the unit we have. We’ll check it out today. I hope it’s just a loose wire somewhere. I think the quickest thing to do first is remove the unit and reseat it. My husband disconnected the BNC connector on the rear antenna yesterday. No joy. We’ll have to explore how to access the front antenna today.  The plane only has 432 TT on the engine, airframe and prop so it hasn’t flown that much. However, it sat for 2 1/2 years prior to our purchase. 

[PJB]

12 hours ago, carusoam said:

Welcome aboard Paula!

Sounds like a wire isn’t working the way it should…

What part of the Mooney World are you in?

Best regards,

-a-

The North Texas area. 

[buddy]

I had a similar problem with my #2 comm transmitting, receiving was fine. When transmitting on my #2, ATC would tell me they had a hard time understanding my transition. After checking the antenna connection on my #2 I also tried reseating my GIA-63W boxes to no avail. The last thing I did was bring it to the avionics shop and we switched the GIA-63W boxes around and reprogrammed them and that seemed to solve my problem. This doesn’t mean that my #2 GIA box is problem free, I think once the boxes were switched it just uses a different path when transmitting. If you’d like PM me and I’ll give you a call and explain in more detail.

[PJB]

Ok. Thanks. But, our com 1 won't transmit at all.  All we get is a side tone.  I'll pass your info along to my husband and will get back to you after he does some other troubleshooting today.  

[AVDB]

Are there any red X in System Status Page?
What error messages do you have?

I recommend to use both G1000 Maintenance Manual for Mooney, doc # 190-00638-01 and the one for STANDARD PISTON/TURBOPROP AIRCRAFT, doc # 190-00907-00, which are available for downloading from Garmin official website.
See GIA 63 and GMA 1347 Troubleshooting sections.

From my experience, first of all clean GIA 63 #1, GMA 1347 D-Sub and coax cable BNC connectors by LPS MICRO-X CONTACT CLEANER or analog, and test COM 1 once again.

Please note that COM antenna MUST always be connected to GIA 63 LRU. Transmitting without an antenna can damage VHF COM transmission path of GIA 63.