Gotta Love Microwave Ovens!

[tinkerer]

This morning, my wife woke me to the news that her coffee failed to heat in our big Sharp. It's a Micro/convection. I turned it on convect. and got heat, light lit, turntable turned, cooling fan running, so, FUSE OK. No microwaves.

Power Transformer
Diode
Capacitor, or, (shudder)
Magnetron.

I could use a bit more information than my electronics training gotten 50+ years ago provides for me. Specifically, would the characteristics of the Magnetron used not need to be matched to the circuitry, namely the cavity and waveguide?

Reason I ask this, I have substituted several different Magnetrons in several different makes and sizes of ovens, and they all seem to get the job done. seem to, they heat stuff similarly to the original equipment. 

BTW, it did turn out that the Magnetron "bought" it, transformer, diode, and capacitor checked out OK, yanked the Magnetron out of our small G.E.; it's a 0.8 cu. ft., the Sharp is 1.6 cu. ft., a considerable difference, yet the Magnetrons appear to be quite identical physically, even having identical mounting dimensions. The Sharp is functioning again quite well. Now, seventy-five bucks for a replacement Mag.......

Thought I would tack this on, just found it tonight, clarifies graphically in my mind, finally, how a cavity magnetron form resonance:

A resonant cavity in the anode block has the function of a parallel resonant circuit: The opposite anode walls of a slot are the capacitor, the detour around the hole is the inductance (with only one turn).
 

Edited November 23, 2018 by tinkerer