JRC JMR-92 Series Field Service Manual page 488

Check the magnetron current on the test menu during the time and if
operation becomes unstable, bring the radar unit back to STBY mode and
restart transmission after allowing for an interval of 5 to 10 minutes.
(3) After transmitting on a long range for about fifteen minutes, return to the service engineer
menu and adjust the tuning. Perform the adjustment in the service engineer menu until
the tuning display bar on the display unit reaches the 8th calibration mark. With the
service engineer menu open, also make sure the magnetron current is shown between
the 6th and 9th calibration markings.
(4) Finally, initialize the transmission time in the service engineer menu.
This completes magnetron replacement.
Chapter 4 Replacement procedure 4-268