Upgrading the 840's stock 120mm exhaust fan to 140mm fan.
Cooler Master 840 ATCS rear 120mm exhaust
I'm holding up a 140mm Cooler Master fan over the stock 120mm grill. "Will it fit without anything obstructing it?"
The location of the 140mm fan resides along the crease on the back plate.
Making the initial cut with Rotary tool and reinforced cutting wheel before using Jigsaw
Using Jigsaw with 18 TPI metal cutting blade
Using rounded side hand file to clean up burrs along the edge of the cut.
140mm opening is cleaned up, next is drilling mounting holes for 140mm fan