samsung i9500 give me trouble plz help

heloo sir i have a i9500 version 5.0.1 with imei 045 i m try to repaier with z3x after repaier imei null or baseband unknown so i m try to repaier again its show ssv not found so i try to downgrade the phone but phone not connect in downlode mode but connect with pc in on mode properly i m also change the charging jack but problem is same plz give the solution

Thx in advance