JRC JMR-92 Series Field Service Manual page 251

Step 3 Replace the modulator circuit board.
Remove the two screws (M4) holding the metal sheet and the radiating plate of the modulation
circuit board and the six screws (M4) holding the modulation circuit board, to replace the
modulation circuit board. If reusing the heat radiation plate on the modulator, be sure to install the
insulation sheet between the TR5-8 and the heat radiation plate so that it is straight. After
replacing the modulation circuit board, assemble the unit in the reverse order of the disassembly
procedure. Do not forget to tighten the bolts or screws, and make sure that the cables are
connected.
Step 4 Operation check
After completing the replacement work, turn On the safety switch and check operation by
following the procedure below.
(1) Turn On the Display unit. After the preheat countdown is completed, start transmission
and check that the radar image appears without error.
Transmit the radio wave in long pulse range mode and open the service engineer menu
to check that the magnetron current stands between the 5th and 7th calibration markings.
This completes modulation circuit board replacement.
Modulation
circuit board
Remove the six
screws.
Remove the two screws.
4-31 Chapter 4 Replacement procedure