What was found
LOST ALL POWER TO AIRCRAFT AT THE GATE WITH APU ON WHEN THRUST LEVERS PULLED TO SHUT OFF. BATTERY MASTER WILL NOT TURN ON. PERFORMED OPS CHECK OF MAIN BATTERY AND APU BATTERY IAW CRJ 700 AMM. OPS CHECK GOOD AT THIS TIME. PERFORMED THREE START/STOP SEQUENCES OF THE APU IAW CRJ 700 AMM. OPS CHECK GOOD AT THIS TIME. PERFORMED THREE ENGINE START/STOP SEQUENCES IAW CRJ 700 AMM. OPS CHECK GOOD AT THIS TIME. NO DEFECTS NOTED.