ISOLATE TROUBLESHOOTING ALERT MALFUNCTIONS
a. If the radiation visible and audible indicators do not stop when you are testing
the deadman feature you can isolate the fault to a maladjusted or malfunctioning
Dentotime pcb D1.
(1) The deadman feature permits the premature immediate termination of
X-rays. To test this feature you use the following procedure.
Set the object/exposure time selector to 3.2 seconds.
(b) Cover the collimator with a leaded cover cap.
Move at least 6 feet from the X-ray head to avoid exposure to
(d) Make an exposure with the exposure button. Count 5001 (five-
thousand-one) which equals approximately one second. Release the exposure button,
the audible and visible radiation indicators must terminate immediately.
(e) Disconnect the unit from the power supply immediately in the event
the radiation visible and audible indicators do not stop.
(2) Remove and replace the Dentotime pcb D1, and adjust it per procedures
in Lesson 2, paragraph 2-5, before returning the device to service.
b. If the audible signal and red radiation emission light come on together, but the
exposure time is noticeably longer than the time selected, the problem is caused by
either a timer malfunction, defective scissors arm wiring, or a defective X-ray head.
(1) To determine if the malfunction is due to an incorrect exposure time
(improper timer function) refer to Lesson 2, Verification/Calibration of the Inter-oral
Dental X-ray, paragraph 2-5a through f.
(2) To determine if the malfunction is due to defective scissors arm wiring,
or a defective X-ray head, use the following procedures.
(a) Select the shortest exposure time, 0.066 second.
(b) Make an exposure.
Observe the red radiation emission light (visual) and the audible