TM 11-5840-217-34-1
CHAPTER 6
FIELD ADJUSTMENTS
6-1. +250 VDC ADJUSTMENT
a. Connect the multimeter test leads to pin L(-) and pin G(+) of test point (TP) 1801.
b. Loosen the locknut and adjust +250 ADJ pot R1819 for a reading of 250 +2. 5 VDC on the meter.
c. Tighten the locknut and remove the test leads.
6-2. REP-RATE ADJUSTMENT
Note: Transmitter must be radiating when this adjustment is made.
a. Connect the oscilloscope test probe to PRE-TRIG TP502 and set scope time for . 1M sec.
b. Loosen the locknut and adjust PRF SET pot R517 for a period of 540 ;sec.
c. Tighten the locknut and remove the test leads.
6-3. MAGNETRON CURRENT ADJUSTMENT
Note: Transmitter must be radiating when this adjustment is made.
a. Place the meter switch in the MAG CUR position.
b. Adjust the MAG CUR ADJ knob for a reading of 0.7 (14 ma) on the meter.
6-4. RECEIVER TUNING
Warning: Extremely high voltages are present in these units when the transmitter is radiating; avoid any contact with
the equipment.
a. Turn the LO ADJ screw fully cw and then ccw 4 1/2 turns.
b. Place the meter switch in the AFC AM position.
c. Turn AFC ADJ pot R402 to midrange.
d. Connect the multimeter (-500 VDC range) to TB201-9 and ground.
e. Loosen the locknut and, while holding the AFC switch in the OFF position, adjust pot R401 for a reading of -415
VDC.
f. Release the AFC switch and turn the LO ADJ screw one turn ccw. Crystal current should be indicated. If not, turn
the ATTEN 1 ADJ screw cw.
g. Press the RADIATE switch.
h. Turn the LO ADJ screw cw until the crystal current stops sweeping. Continue turning the screw slowly until the
crystal current peaks. At that time, the klystron should be locked on.
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