Customer Questions and Answers for Magnetron (Microwave) by Whirlpool

Hello Alf, You could test the transformer and the magnetron to see if they are bad. Using multi-meter measure the tranformer with the leads disconnected Primary, secondary and Filament to ground. You should read less than 1 ohm on the primary and secondary. Filament to ground should be 0 ohms. Measure resistance of primary and filament should be infinite. Check the magnetron touch the leads to f and fa terminals should be approximately 0 ohms and measure from filament to chassis and should be 0 ohms. Anything other than these readings means the part is bad. If the parts check ok then you would want to replace the control board. You can test this with a multi-meter TJMA-DMT3. Here is a link on how to use a multi-meter. http://forum.appliancepartspros.com/oven-repair-including-ranges-cooktops/4810-how-check-continuity-ohmmeter.html