TM-9-1240-401-34&P Technical Manual for M109 Telescopes and Mounts Download
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TM 9-1240-401-34&P I 5-26. M117/M117A2 PANORAMIC TELESCOPE FINAL INSPECTION AND ADJUSTMENT - continued I i. AZIMUTH ERRORS (800-MlL STEPS) AND BACKLASH (AZIMUTH MECHANISM) - continued 5 6 7 8 9 10 11 4 Again rotate azimuth knob (2) approximately one full revolution clockwise. Rotate azimuth knob (2) slowly counterclockwise until telescope reticle is in coincidence with collimating projector reticle. Re- cord readings. Be careful not to overtravel coinci- dence point. If coincidence point is passed, repeat this step. Difference between readings in steps 3 and 4 is amount of backlash and must not exceed 1.0 mil when read on azimuth counter (3) and 1.5 mil when read on reset counter (4). Rotate azimuth fixture ring (1) counterclockwise to 1600 mils. Repeat steps 2 thru 5. Azimuth counter (3) and reset counter (4) should indicate 4800 mils. Repeat steps 6 and 7 above, every 800 mils, until azimuth fixture ring (1) completes two full revolu- tions. Replace azimuth counter (3) (ref. para 5-23) if readings exceed tolerance in step 5. Replace reset counter (4) (ref. para 5-23) if read- ings exceed tolerance in step 5. If backlash in azimuth mechanism exceeds toler- ance, adjust plug (5) or retainer (6). Check for binding or loose gear trains (ref. para 5-23). 5-56