KX125 question

It has been a few weeks since I added glide slope receiver (KN75) and ILS
indicater (KI209A) to my trusted KX125. All was well, and they track ILS just
fine. But when tracking VOR, com transmission would somehow block off nav
signal and both indicators (KI209A & KN125 built-in) would show "off" flag. It
acts like those old 1&1/2 nav/com radios.

I do not remember if my KX125 acted this way before I added KN75 & KI209A to
it. I tried disconnecting the KI209A from it, but it still show "off" flag on
its built-in indicator when transmitting. I did not try to disconnect the KN75
because it is hard to get to.

Questions:

1. When transmitting from my other com radio, KX125 & KI209A do not lost nav
signal. Does that rule out antenna problem?

2. I also noted that the "comm audio" line is not the shield type. Could this
be the problem?

3. Is it likely the KN75 might be the problem, does it worth the time to
disconnect it from KX125 and see if KN75 is the problem?

Many thanks,

Robin Hou