Pin 8 of the radio goes to the KN72:
Pin 8 is ILS energize. It switches the external converter (KN-72 in this case, but could also be Sandel or Aspen for example) a discrete signal to indicate if the NAV is operating in VOR mode, or that it is operating in ILS (VOR + GS mode).
Pin H is the composite nav signal, which contains the NAV signal to be processed by the external converter.
Based on your reply, the Sandel has a higher impedance then the KN-72 which could be why the Sandel works, and the KN-72 doesn’t.
“The VOR/LOC Compsite Level may be adjusted to interface with an external converter/indicator. "
By using the KN-72 you have added an additional (external) converter. So you may adjust the signal.
As this composite signal only contains VOR/LOC data the GS should still work.
I have just read on the Socata owners’ group this:
“The KX155A is plug compatible with the KX155 and there are 8.33 KHz versions available”
I cannot find anything on google.
The KX165A is available in 8.33.
Need a 8.33 radio soon I would take one but haven´t found any 155A/8.33 capable “version”, too…
There isn’t an 8.33 version of the KX155A – you have to use the 165A.
The closest could be the TRIG TY96/97 models – but I dont know the tech details.
