ISOLATE MALFUNCTIONS TO THE COMPONENT LEVEL
Troubleshooting is a systematic method of isolating malfunctions by means of
tests based on symptoms. It is intended to reduce the amount of time normally required
to locate maladjustments and defective components. It is also intended to restore
equipment to a serviceable condition. When you isolate dental chair malfunctions you
use a troubleshooting guide. Refer to the Dental Chair Model JSR Troubleshooting
Guide in the appendix. Based on the observed problem, the guide tells you a probable
cause, how to test for that cause, and if the test is positive, the corrective action to take.
If the test shown is negative, check for other chair problems and troubleshoot them.
The troubleshooting guide supplements your experience as the repairer. As you gain
experience isolating malfunctions in the chair, you will rely less and less on it. To
perform some of the appropriate tests, you need a digital multimeter.
a. If the chair will not operate (lift), the Dental Chair Model JSR Troubleshooting
Guide shows 13 probable causes from a list of all possible causes. This lesson covers
the first six of those probable causes. See the guide, "Probable Cause" column.
(1) The power cord is not plugged in to the supply receptacle or that the
circuit breaker is off. The testing procedure for this probable cause is to visually inspect
the power cord and the circuit breaker. See the guide, "Testing Procedure" column.
(a) If the power cord is not plugged in or the circuit breaker is off, the
action to take to correct the problem, according to the "Corrective Action" column, is to
plug in the cord or turn on the circuit breaker.
(b) If the visual inspection shows the power cord is not unplugged and
the circuit breaker box is on, you continue to the next probable cause.
The building power supply is faulty.
(a) Use a voltmeter to check for a reading of 115v or 220v, as
applicable, at the power supply receptacle.
(b) If there is no reading, the problem is with the building power supply.
The corrective action is to notify the proper personnel.
(c) If there is a reading, and the chair still won't operate, you go on to
the next probable cause.
(3) The chair power cord is not plugged into the gray cord at the rear of the
lift. Visually inspect the chair power cord.
(a) If the chair power cord is disconnected, connect it.