TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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(4) Adjust the INTENSITY screw clockwise to brighten the wave form, but not to the point where a bright spot occurs at the beginning of the wave form. Caution: Too much intensity can damage display screen phosphor coating. (5) Adjust the ASTIG screw to the sharpest wave form. (6) Adjust the FOCUS screw to the sharpest wave form. (3) Adjust the reflectoscope using the master checking gage. (a) Pour water into the master checking gage, part No. 10935515, to the “FILL” level (five inches from top). Place the marked defect portion of the gage facing the operator. Note. Fresh water should not be used for test. Allow the water to stand twenty-four hours before use. Add approximately one fluid ounce of anti-coalescent agent, such as “Jet Dry”, to each ten gallons (37.85 liters) of water. The water, master gage, and test cylinders should be at room temperature during test. Note. Wipe all air bubbles from the cylinder wall. Bubbles may cause a false alarm signal. (b) Remove the protector from search fixture probe. Place the search fixture on the master checking gage (fig. 6-54), with the UPPER-LOWER switch facing the operator. Place the search fixture UPPER-LOWER switch to “UPPER”. Figure 6-54. Ultrasonic search fixture installed on master checking cylinder. (c) Connect the cable to the search fix- ture, and to the reflectoscope at connector “R”. (d) Rotate the search fixture handle counterclockwise to move the probe to the uppermost position. The wave form on the display screen will be similar to view B, fig. 6-53. (e) Rotate the search fixture handle clockwise to move the probe downward. Rotate the search fixture handle until the echo pulse, or spike (view C, fig. 6-53), is shown on the display screen when the fixture pointer alines with the master checking gage defect. (f) Move the search fixture probe upward and downward until a maximum pulse is ob- tained on the display screen (view C, fig. 6-53). (g) Adjust the PULSE TUNING knob (on pulser / receiver unit) to obtain the maximum pulse height on the display screen. (h) Adjust the SENSITIVITY control knob (on pulser / receiver unit) to provide an echo pulse height of 2-1 / 2 inches (view C, fig. 6-53). (i) Place the search fixture UPPER- LOWER switch to “LOWER”. 6-63