Repair Magsafe 2 Charger?

Hi all,

I searched around for this, but most charging-related questions lead to troubleshooting the DC-IN, battery, etc and I couldn't find this issue specifically.

I'm an Apple Tech who doesn't have a background in electrical engineering - and made the mistake of daisy chaining a couple surge protectors together. They were like this for a number of months. This caused a few of my Magsafe chargers to go out. I'm curious whether the chargers can be repaired.

The symptoms:

• The charger does not light up when connected to a machine (regardless of the machine).
• The system battery icon shows that it's charging, but the status is "Battery is not charging." If I leave the cable connected overnight, the machine will usually charge up.
• Hence, it seems the charger is providing power, but at a much reduced rate from what it should.

Is there a way to restore it to its former functionality?