JRC JMR-92 Series Field Service Manual page 490

Step 2 Remove the tightening metal fitting.
Loosen the upset head bolt (one M4 bolt), and slide the tightening metal fitting, located between
the modulator and the circulator, to remove it. The magnetron is installed within the modulator.
Modulator
Circulator
Tightening metal fitting
Circulator
Tightening metal fitting
Remove the screws.
Chapter 4 Replacement procedure 4-270