David B Charleston , SC October 21, 2017 Appliance: Whirlpool Microwave Hood Combo WMH73L20AS0 Whirlpool Microwave Wmh73l20as0 / : Grill vent on microwave broke at attachment points. How to replace Grill-Vent. Installed new vent, simple fix using the 2 screws that had held original vent. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes