AFS4500 problem - VOR OBS keeps resetting to 000 (linked to GNC255)

[mikeeeee]

Hi there

When a VOR is tuned in, every time I change the OBS radial using the CRS selector on the AFS, it stays on new CRS for about 3 seconds, then defaults back to 000 every time.

Anyone else experienced this and know what the issue could be?

Thanks

[amekler]

sounds like a setting issue on either the gnc255 or 4500
I would call tech support from sitting in the airplane
Alan

[Shawn McGinnis]

That sounds like a broken EFIS TX -> GNC255 RX wire. The EFIS is trying to set the value but the 255 isn't hearing the command.