TM-9-2350-275-BD Battlefield Damage Assessment and Repair for M113 Family Download
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TM 9-2350-275-BD COMMUNICATIONS SYSTEM Procedural Steps (Cont): P. Set the MODE SELECTOR SWITCH (3) to the receive only (right) Position. q. Depress and hold the TONE CALL BUTTON (25). A tone should be heard in the earphones. Rotate the FREQUENCY TUNING KNOB (27) until a zero beat is obtained. While rotating the FREQUENCY TUNING KNOB (27) the tone should be heard to progress from a high pitch to a low pitch then to a high pitch again. The proper setting of the FREQUENCY TUNING KNOB (27) is the point at which the tone is at its lowest pitch or totally absent. Note the relative positions of the index line and the frequency graduation line through the FREQUENCY DIAL VIEWING WINDOW (5). If the index line is within 1/5 of a frequency graduation (5 KHZ), no adjustment of the index line is necessary Proceed after releasing the TONE CALL BUTTON (25). if the index line is not within 1/5 of a graduation (5 KHZ) the following adjustments must be made: (1) Release the TONE CALL BUTTON (25). Using a screwdriver, remove the INDEX LINE ADJUSTMENT (4) plug. NOTE This adjustment is quite stiff. Care should be exercised to not change the frequency setting while adjusting the index line. (2) Insert the screwdriver into the hole disclosed and contact the index line adjustment. Rotate the adjustment right or left until the index line exactly corresponds to the selected frequency graduation line. (3) Replace the INDEX LINE ADJUSTMENT (4) plug. (4) Check the setting by repeating steps (q) and (r). When no adjustment is required, proceed to the next step. s. Return the MODE SELECTOR SWITCH (3) to the Simplex position (left). t. Set the PRESET CHANNEL/CONTINUOUS TUNE SELECTOR SWITCH (18) to the preset #1 position. u. Set the PRESET CHANNEL BAND SELECTOR (11) to correspond with the desired band. Frequencies between 20.0 and 35.75 MHZ are set on Band I (switch up); frequencies between 35.8 and 51.5 HMZ are set on Band II (switch down). Band selections are indicated by the BAND INDICATOR lights (13). v. Open the PRESET LOCKING SCREW ACCESS COVER (19) on the front panel and loosen the PRESET LOCKING SCREW (6) marked "1" by turning the locking screw counterclockwsie until the slot is at right angles with the red circle. To release the preset locking screw, use the special key (not shown) attached to the case of the radio. 11-35