Microwave advise please

[Nevillet]

Hi All,

I am trying to diagnose a faulty microwave oven and have checked the following components.

Transformer – The primary and secondary windings have low resistances and no shorts to earth or between pri/sec.

The high voltage capacitor (1.05uF/2200V) measures fine with no shorts to earth.

The diode is not shorted or open circuit and when connected to a 9V battery drops 4V.

The magnetron has a low resistance across the terminals and has no resistance to earth.

I’ve put a clamp meter around one of the primary lines to the transformer and measured about 4A (240V) when the microwave is ‘on’.

A cup of water in the microwave does not heat in any way.

My gut feeling is that the magnetron is suspect but I’d appreciate any opinions on this.

Many thanks.