Yes shut off gas supply and disconnect electric cord. Now do not cook on it until you fix everything. Then after removing star burner covers, put penetrating oil at outer margin of all the center brass (venturi nozzle) nuts (5 in total) and leave in for 1-2 days. All 5 have to be removed with appropriate sized socket and wrench. Then just lift the whole pan and support it on both sides to access for work on the inside. There are no much parts inside except gas simmer controller, spark module, wire harness, gas tubes, etc. Make sure you check for good tightness of the green ground wires. Also wipe to dry any remnants of penetrating oil you used before tightening back the brass nozzles. There have been hundreds of complaints about Thermador cooktops. Poor quality. Good luck:)