JRC JMR-92 Series Field Service Manual page 406

Step 4 Replace the modulator circuit board.
Remove the screws (nine M4 screws) holding the modulator circuit board in place and
disconnect the cables connected to it, then replace. If you are reusing the heat radiation plate on
the modulator, be sure to install the insulation sheet between TR17, TR18, and the heat radiation
plate so that it is straight.
After having replaced the modulator circuit board, reassemble the unit by following the
disassembly procedure in the reverse order. Do not forget to tighten the bolts or screws, and do
not forget to reconnect the cables.
Step 5 Operation check
After having completed the replacement, close the cover, turn On the safety switch and check
operation by following the procedure below.
(1) Turn On the Display unit. After the countdown is completed, start transmission and check
that the radar image appears without error.
Transmit the radar 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 modulator circuit board replacement.
Chapter 4 Replacement procedure
Remove the nine
screws (M4).
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