Strange GTN 650 Issue

wnplt · #1 12-04-2019, 08:01 PM

So I was flying a couple ILS approaches today and on the second one the GTX 650 would not transmit to ATC. The GMA245 audio panel mic switch light flashed as it was transmitting but no TX indication above the Freq on the GTN, had to switch to com 2 and that was working. I tried rebooting the GTN and the audio panel but still could not get GTN to transmit. It was receiving fine. I decided to fly back to home base and tried it again and the TX annunciated this time and was transmitting again. Radio has been flawless since July. Thought maybe a broken wire or pin issue but it failed and then 10 minutes later was working again and could not duplicate. Not sure if it?s the audio panel not keying the GTN or the GTN just not transmitting. Thinking if it does it again to power off audio panel so to force failsafe and see if the GTN transmits. Anyone have any ideas? Steve do you have any ideas?

Thanks,
Steve

RV8iator · #2 12-04-2019, 08:40 PM

I would make sure it is seated and tight in the rack. Don?t overtighten the allan screw, just snug.

rleffler · #3 12-05-2019, 05:59 AM

I had a similar issue with my 650. Mine turned out to be the PTT switch going bad.

As an intermittent issue, they are tough to isolate. Remember, when you're flying there a lot of vibrations, that aren't present on the ground. Put an ohm meter the the wires and shake them to see if there are any connections that may not be solid.

Tim Lewis · #4 12-05-2019, 06:21 AM

I had a similar experience with a 530W. Turning off/on with power switch didn?t fix it, but pulling *both* breakers and rebooting did resolve it.

Walt · #5 12-05-2019, 06:21 AM

If you're not getting the TX indication on the 650 I would start looking at the key line from the 245 to the 650.

wnplt · #6 12-17-2019, 07:43 PM

Thanks guys... this was a tough one to troubleshoot but it did turn out to be a cold solder sleeve that spliced the mic key and the TX interlock lead to the com 2.

Walt · #7 12-18-2019, 07:18 AM

Quote:

Originally Posted by wnplt

Thanks guys... this was a tough one to troubleshoot but it did turn out to be a cold solder sleeve that spliced the mic key and the TX interlock lead to the com 2.

This has been hashed around in the past but this is a good example of why I would never use a solder sleeve for a splice, solder sleeves were designed to be used as shielded cable terminations not wire splices.

wnplt · #8 12-18-2019, 08:46 PM

Good to know! Thanks...

romaja · #9 12-19-2019, 09:52 AM

Quote:

Originally Posted by Walt

This has been hashed around in the past but this is a good example of why I would never use a solder sleeve for a splice, solder sleeves were designed to be used as shielded cable terminations not wire splices.

What type of splice do you recommend for the smaller gauge wires? Crimp type?
Thanks
Jim

Walt · #10 12-19-2019, 12:10 PM

Quote:

Originally Posted by romaja

What type of splice do you recommend for the smaller gauge wires? Crimp type?
Thanks
Jim

AMP PIDG used with an AMP crimper is my go to, never had one fail yet.
Hand solder with double wall adhesive shrink is #2.