TM-9-1240-401-34-P

TELESCOPE MOUNT M146: M118A2 AND M118A3; TELESCOPE MOUNT M145: M145A1; PANORAMIC TELESCOPE: M117 AND M117A2; FIRE CONTROL QUADRANT: M15; PERISCOPE: M42

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

JULY 1993

TM-9-1240-401-34-P - Page 121 of 590

TM9-1240-401-34&P

MALFUNCTION

TEST OR INSPECTION

LOCATION

CORRECTIVE ACTION

CROSS-LEVEL MECHANISM

2. CROSS-LEVEL MECHANISM KNOB(2) IS ERRATIC

AND ROUGH DURING MOVEMENT.

Check for worn wormshaft.

Replace wormshaft assembly

(ref. para 4-13).

3. CROSS-LEVEL MECHANISM KNOB (2) EXCEEDS

0.5 MIL BACKLASH.

Step 1. Check for worn bearings.

Replace wormshaft assembly

(ref. para 4-13).

Step 2. Check for worn or bent wormshaft.

Replace wormshaft assembly

(ref. para 4-13).

4. CROSS-LEVEL MECHANISM KNOB (2) REQUIRES

TORQUE IN EXCESS OF 11 POUND-INCHES

(1 .24 N-M) TO ROTATE.

Check for worn or bent wormshaft

and/or bearings.

Replace wormshaft assembly

(ref. para 4-13).

LEVEL ASSEMBLY

5. NO ILLUMINATION IN CROSS-LEVEL (3) OR

PITCH LEVEL (4).

Observe visually.

a. Replace burned out LEDs

(ref. para 4-15).

b. Replace defective toggle switch

(ref. para 4-15).

c. Clean or replace defective

lens cap (ref. para 4-15).

4-7