(d) Determine if the red radiation emission light and the audible signal
both come on simultaneously and go out simultaneously.
(e) If the indicators come on together but the exposure is noticeably
longer (0.7 to 1.0 second), expose a periapical film. Develop the film.
1 Determine that the X-ray head needs replacement if the
developed radiograph is blank (transparent).
2 Determine that the X-ray head is OK, but that the malfunction is
in the scissors arm wiring, if the developed radiograph is black.
ISOLATE MECHANICAL MALFUNCTIONS
a. If the tube head does not rotate from stop to stop for 540 (1 1/2 turns) there
is a malfunction in the rotational parts. Refer to figure 3-14.
Figure 3-14. Tube head rotational stop.
b. If the X-ray head does not return to 45 by itself when you release it, the
friction pad requires adjustment. Refer to quarterly PMCS procedures in Lesson 1,
paragraph 1-4b(3)(a) through (e).
c. If the tube head drifts, the brake is malfunctioning. Adjust the brake. Refer to
Lesson 1, paragraph 1-4b(4)(a) and (b).