I'm posting this in hopes that it will benefit someone in the future. While I ran into this problem, I did many google searches but couldn't find any helpful info. So here it is:
THE SETUP:
My panel is G500, GTN 750 and 650, GTX 330ES, and a GDL 88. I needed to change the tail number (flight ID) on my 330ES transponder.
THE PROBLEM:
In order to change the tail number on the 330ES I needed to go into configuration mode by holding the FUNC key when powering on. But the 330ES will only stay in the configuration mode for a few second. Then it starts a "self test" and takes itself out of the configuration mode.
A local mechanic at my field suggested that I send the unit to Garmin for service.
THE SOLUTION:
I figured that the 330ES shouldn't go into self test while in configuration mode. An external force must be initiating the test. So I pulled the circuit breakers that interfaced with the 330 one by one. Finally I found that the GTN 750 was the issue. When the GTN750 CB was pulled, the 330 would stay in configuration mode. Voila!
THE SETUP:
My panel is G500, GTN 750 and 650, GTX 330ES, and a GDL 88. I needed to change the tail number (flight ID) on my 330ES transponder.
THE PROBLEM:
In order to change the tail number on the 330ES I needed to go into configuration mode by holding the FUNC key when powering on. But the 330ES will only stay in the configuration mode for a few second. Then it starts a "self test" and takes itself out of the configuration mode.
A local mechanic at my field suggested that I send the unit to Garmin for service.
THE SOLUTION:
I figured that the 330ES shouldn't go into self test while in configuration mode. An external force must be initiating the test. So I pulled the circuit breakers that interfaced with the 330 one by one. Finally I found that the GTN 750 was the issue. When the GTN750 CB was pulled, the 330 would stay in configuration mode. Voila!
