Figure 6-54. Ultrasonic search fixture installed on master checking cylinder.

(4) A d j u s t t h e I N T E N S I T Y s c r e w

c l o c k w i s e to brighten the wave form, but not to

the point where a bright spot occurs at the

beginning of the wave form.

C a u t i o n : 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

( f i v e inches from top). Place the marked defect

portion of the gage facing the operator.

N o t e . Fresh water should not be used for

t e s t . Allow the water to stand twenty-four hours

before use. Add approximately one fluid ounce of

a n t i - c o a l e s c e n t 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

c y l i n d e r wall. Bubbles may cause a false alarm

signal.

Figure 6-54. Ultrasonic search fixture

(b) Remove the protector from search

installed on master checking cylinder.

fixture probe. Place the search fixture on the

master checking gage (fig. 6-54), with the

UPPER-LOWER switch facing the operator.

t u r e , and to the reflectoscope at connector "R".

Place t h e s e a r c h f i x t u r e U P P E R - L O W E R

(d) Rotate the search fixture handle

switch to "UPPER".

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

t h e 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-

t a i n e d 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