works but not heating food

kenmore microwave not heating. went through all identified components and tests of same - diode, relay, capacitor, transformers, magnetron, switches, fuses, sensors/thermostats.

diode - 9v battery check with DMM, checks okay not open or shorted.

capacitor - resister check okay, uF checks 1.03 for 1.05uF rated. no defect - but curious no spark or pop when attempt to discharge after each test.

Transformer- resisitance checks okay on primary, secondary, and to ground.

magnetron - terminals and to ground resistance checks okay, nose of antenna okay, visual no defects of burns.

relay - 120 v to transformer and checked on various power scales 1-10.