[aprssig] KPC3+ lost settings

[Andrzej AB9FX]

Few weeks ago, digi SP3KWA-4 working with Kantronics KPC3+ v.9.1 lost all 
settings. I put new battery and put all settings to tnc. After a week tnc 
was reset again. TNC is not connected to any computer nor external device, 
just tnc+radio+power supplay. Did anybody encounter the same problem? Could 
be any packet string messing up tnc? or any other reason?
thanks
Andy AB9FX (SP3LYR)