I took my 2980 PSU apart to play with it and see if the voltage would adjust some and it will.
Can only get to the small adjustment pots with the cover removed the access panels don't open enough up to get to them.
See Video Voltage Adjustment is 11.9 to 12.9 This is with no load I Don't have all my connectors to make up the pig tails to load test it yet. I have pictures but can't figure out how to post them.
https://youtu.be/7wVcZwyZ6jg