ABB Drive Module Fault

We have roughly 400 abb robots, tonight we have replaced 25 drive modules on multiple robots and are currently down due to running out of replacement parts, they are S5 Mig welders 1600 drive, we had a power outage earlier today at 5pm, and every since it came back on we have had this problem constantly, even with brand new drives put in directly from ABB within an hour the robot going into system failure for Drive Module Fault, has anyone ever experienced this problem that can shed light on what may be causing this problem?

Check that your mains supply is within tolerance on all phases.
When you say S5 do you mean IRC5?