MM Arming Issue

[Dadx2mj]

I have a well used Mamba Max / 5700 combined with a Spektrum DX3S radio. This set up has been working fine for a very long time until recently. It now takes a very long time to arm. I turn the radio on then plug in the battery, the switch was hard wired long ago, it then gives the initial chimes then takes well over a minute to give the second set of chimes indicating the system is armed. In between the two sets of chimes the steering will respond but no throttle response. The firmware is the latest offered and I have changed the arming time from 1.0 to 1.5, and then back to 1.0 with no difference. This only happens when the truck has set over night , if I switch in a new pack the systems arms in a normal time frame. Is there a setting that might fix this or is my system just getting old and this is a symptom indicating impending doom?