JRC JMR-92 Series Field Service Manual page 513

Step 2 Replace the modulator circuit board.
Remove all the cables connected to the modulator circuit board and remove the screws holding
the modulator circuit board (six M4 screws) and the screws holding the heat radiation plate (two
M4 screws) and remove the modulator circuit board.
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
make sure that the cables are connected.
Remove the two cables.
Step 3 Operation check
After having completed the replacement, 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.
Remove the six screws.
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Modulator circuit board
Remove the two screws.
Chapter 4 Replacement procedure