Jump to content
Chris S.

Radio not transmitting

Recommended Posts

Hi,

I've had a gremlin for awhile now in my 2011 CTLS where when I depress the push-to-talk switch I can see that the intercom is registering the switch is down but the COM radio is not transmitting. Usually when this happened in the past it would have fixed itself next time I started up the plane but after a recent annual it got worse. The shop looked and found a frayed wire in the bundle in the front of the cargo area and spliced it. That fixed it for a few flights and now it's back to not working again.

Anyone have ideas of what else it could be? I would assume the splice is bad maybe but when I looked at it it seemed fine (I didn't do anything except look and poke and pull a little). 

 

Share this post


Link to post
Share on other sites
13 hours ago, CTDan said:

I had a bad mic jack once. 
 

The symptoms were very similar. 

I've tried both sets of plugs, would that show if it was the jack? The mechanic who looked at it last said he was surprised that the jacks used spade connectors rather than being soldered.

Share this post


Link to post
Share on other sites
4 minutes ago, Chris S. said:

I've tried both sets of plugs, would that show if it was the jack? The mechanic who looked at it last said he was surprised that the jacks used spade connectors rather than being soldered.

I wouldn't have thought that both jacks would go bad at the same time.

Also, I'd think that you wouldn't hear yourself through the headset if it was the jack.

Have you tried another headset?

Have you adjusted your squelch?

Share this post


Link to post
Share on other sites
18 minutes ago, CTDan said:

I wouldn't have thought that both jacks would go bad at the same time.

Also, I'd think that you wouldn't hear yourself through the headset if it was the jack.

Have you tried another headset?

Have you adjusted your squelch?

Yes, have tried multiple headsets and played with squelch, turned everything on off, etc.

Sounds like it's probably somewhere further down in the wiring then, will try and get some time again with the shop.

Share this post


Link to post
Share on other sites
5 minutes ago, Chris S. said:

Yes, have tried multiple headsets and played with squelch, turned everything on off, etc.

Sounds like it's probably somewhere further down in the wiring then, will try and get some time again with the shop.

Unfortunately, I am only able to offer the simple trouble shooting solutions.

Hopefully one of the more knowledgeable members will be along shortly with some other ideas.

Good luck. Sorry I wasn't able to help more.

Dan

Share this post


Link to post
Share on other sites

This may be a very long shot, and don't know what brand radio you're dealing with.  I recall seeing something somewhere around antenna connector from coax in plane not being mounted internal to tray, but on the back side, and this lead to reduced engagement in the radio connector through the tray and then into the connector.  Maybe re-rack the radio and make sure all is connected up tight with the coax, ditto on the antenna end.

I had a static / poor signal situation this year, cleaned antenna grounds which were not all that bad by eye, and became crystal clear.

Share this post


Link to post
Share on other sites

Radio is a Garmin GTR 225. I can pull one of the panels off and have a look at the back to see if the connectors are loose.

 

Thank you both for the suggestions and help. Will see what the shop says when they get back to me as well.

 

 

Share this post


Link to post
Share on other sites

I think I would start with pulling the radio and re-seating it in the tray. While the radio is removed I would shine a flashlight in the rear of the tray and look at the connectors. Try and see if all of the pins or socket are pushed into the plug like they should be. If the intercom light changes, but the radio does not show the transmit indicator the problem is probably at the connection on the back of the radio. 

Share this post


Link to post
Share on other sites

I agree with Tom on re-seating the radio.   I had a similar instance with my transponder.  I even sent it in for repair and testing all came out it was in working order.   Re-installed and still was intermittent.   Long story short, found out that the re-installation (or re-seating) was off by a mm.  Once good contact  and properly seated - worked perfectly

Share this post


Link to post
Share on other sites
On 10/19/2020 at 11:11 AM, Tom Baker said:

I think I would start with pulling the radio and re-seating it in the tray. While the radio is removed I would shine a flashlight in the rear of the tray and look at the connectors. Try and see if all of the pins or socket are pushed into the plug like they should be. If the intercom light changes, but the radio does not show the transmit indicator the problem is probably at the connection on the back of the radio. 

This fixed it! I pulled the center panel out and unplugged the coax cable from the radio, gave a bit of a turn to the place where it connects on the radio then reconnected the cable. Gave the other connector a good firm push in and wiggled the wires a bit. When I powered the avionics back up the radio was WAY louder and I was able to transmit from both headset jacks. I noticed I also have a really annoying whine on the intercom (goes away when the intercom is switched off) but I can live with that for now. 

Thanks everyone for all the help!

Share this post


Link to post
Share on other sites

Is the whine on the intercom only when the airplane is running? It can be a couple different things. If it started after you removed the panel you likely need to remove and re-seat the plug. The other thing is ground loop noise from electric equipment, most likely the GPS. That can be checked by shutting the breaker off while the airplane is running.

Share this post


Link to post
Share on other sites
1 hour ago, Tom Baker said:

Is the whine on the intercom only when the airplane is running? It can be a couple different things. If it started after you removed the panel you likely need to remove and re-seat the plug. The other thing is ground loop noise from electric equipment, most likely the GPS. That can be checked by shutting the breaker off while the airplane is running.

Good stuff, Tom.

Share this post


Link to post
Share on other sites
3 hours ago, Tom Baker said:

Is the whine on the intercom only when the airplane is running? It can be a couple different things. If it started after you removed the panel you likely need to remove and re-seat the plug. The other thing is ground loop noise from electric equipment, most likely the GPS. That can be checked by shutting the breaker off while the airplane is running.

Whine is happening without the engine running but also pre-dates me fiddling with the radio connectors. I'll try shutting off the GPS via breaker and see if it goes away. It's definitely not a big issue though.

Share this post


Link to post
Share on other sites

Yeah ive got that whine on the intercom too.  Been dealing with that for waaaay to long.   I try to clean contacts etc and it sometimes seems to work but not for long.  I think im gonna give up and buy a new one.     On another note-  I was never able to get the radio on the headset with the intercom powered off.  I thought the wiring was bad or that wasnt an option even though the instruction manual said it was possible.   Years later, i figured out the stereo switch on the headset was the cause of this.  Duh!  

Share this post


Link to post
Share on other sites

a follow up to the whine on the intercom - i removed and inspected and this is what i found ... the pin to #1 (ground) was gone and possibly melted ?? can't tell for sure ...  but if that pin (ground) was completely gone, wouldn't that mean i have no power ?   I am really clueless on this.   To fix, a wire was attached as shown on third photo and the unit thus far works without the whine - can't tell for sure until i  flight test as the whine would happen only in flight sometimes.  Does that wire connection look unsafe ? Thanks in advance for your  inputs 

9F1915A5-BBCD-4CD4-B8FD-B54FE054A15C.jpeg

B52C0FBD-244E-41D8-A4A4-3F12EDEDBE7B.jpeg

D573F1FC-C501-4EB7-AE19-990179C70692.jpeg

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...