Kitchenaid KHMS2056SSS3 microwave not heating

[tgoods]

Kitchenaid KHMS2056SSS3, TR14712308 microwave not heating. It has a cycling, buzzing sound coming from the relay board (see video). The amperage draw rises to around 5 amps every time it buzzes. I've replaced the inverter board, relay board and control board. I haven't replaced the magnetron but it tests good and it still makes the noise even with it disconnected. I'm out of ideas. It's a 36" microwave that's not available anymore so I'm a little desperate. Thanks.
 

 

[PDuff]

A magnetron can still be faulty, even if the filament tests good and no visible damage to the antenna.

A quick way to test it is to engage a cook cycle for one minute.  De-energize the unit and feel the mag.  If it's warm to the touch, it's most likely getting correct voltage and the magnetron itself is bad.

[tgoods]

A new magnetron fixed it. Thanks for your help.