Just reviewed the manual online-looks fairly simple. I did notice this in the troubleshooting area:
PROBLEM: Will not lock into discharge mode.
SOLUTION:
1) Battery’s rated voltage set improperly. Set battery voltage to exactly match that of
the battery.
2) Tx has diode in charge circuit. Remove battery and connect directly to charger, or
contact your radio manufacturer for details.
3) Battery is already discharged.
4) Defective cell in pack. Replace battery.