William M Glen Rose , TX June 12, 2014 Appliance: Jenn-Air Electric Downdraft Surface Unit JED8430ADB Jenn-Air Cooktop Jed8430adb: Broken stove top. How to replace Cooktop Glass Top. Turn off elec. Disconnect undercounter vent pipe . Raise range top a few inches and support from below . Remove screws under edge of top using screw holes in new top as guide [not all screws need to come out] .Remove two screws from center of lip of downdraft opening . Lift off old top . Install new top in reverse order . 13 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 1-2 hours