What was found
FA REPORTED ACRID SMOKE SMELL AFTER PUSH BACK NEAR ROWS 10-12. NO SMOKE DETECTED. RETURNED TO GATE. CHECKED ALL PED POWER OUTLETS, SEAT COMPONENTS INCLUDING UNDER SEAR CUSHION. CHECKED PED POWER UNDER APU POWER AND GROUND POWER . CHECKED CARGO COMPARTMENTS. USED CHARGERS ON ALL AFFECTED ROWS OUTLET. RAN BOTH ENGINES REF A220 AMP 71-00 WITH L/R PACKS ON TO TRY TO DUPLICATE ISSUE, COULD NOT DUPLICATE ACRID SMELL. INSPECTED PED SYSTEM PER A220 AMP 44-20. AIRCRAFT OK FOR SVC. SUSPECT THE ACRID SMOKE SMELL CAME FROM CUSTOMER DEVICE AND NOT AIRCRAFT. (LP# 5868258)