Hello,
I am a novice. Used site and youtube videos to diagnose so far.

Was heating a bowl of water with some potatoes in the Microwave. Was cooking for about 15 minutes or so (water and potatoes were hot) when I noticed the microwave was not on. No loud noise noticed or anything simply all microwave power off. Investigated. Microwave blew 15 AMP fuse (first time in 18 years). Replaced, blew again on start up in about 2 seconds.

Removed leads from Magnetron, replaced fuse. Started MW and blew in 2 seconds again.
Removed Diode - did not blow fuse on start up..... with magnetron connect or not connected.

Replaced diode with a WB27X1160 GE KIT with magnetron connectd blew fuse. NOte I am unsure if diode was orientated right - letters on body of diode on ground to body end as replacement diode came with various connectors and not a dedicated ground end or push connector.

I am wondering if the magnetron is bad or capcitor or transformer. Any suggestions. Really just want to fix it rather than continue diagnose.
Best guess from what I read is replace magnetron and diode (and fuse again) .

I have dis-assembled the unit and pulled the magnetron and it seems to have continuity (I bought a cheap multimeter at Harbor Freight). Doides are definiently no good now

The control board is fine.

Thoughts?