12 Troubleshooting
If problems arise while operating the 9140, this section provides somesugges-
tions that may help you solve the problem.A wiring diagram is also included.

12.1 Troubleshooting Problems, Possible Causes,

and Solutions

In the event that the instrument appears to function abnormally,this section
may help to find and solve theproblem. Several possible problem conditions
are described along with likely causes and solutions. If a problem arises, please
read this section carefully and attempt to understand and solvethe problem. If
the problem cannot otherwise be solved, contact a Hart ScientificAuthorized
Service Center (see Section 1.3) for assistance. Be sure to have the model
number, serial number,voltage, and problem description available.
Problem PossibleCauses and Solutions
Incorrect tempera-
ture reading
Incorrect R0, ALPHA, and DELTA parameters. Find the value for R0, ALPHA, and
DELTA on the Report of Calibration.Reprogram the parameters into the instrument
(see Section , Calibration Parameters). Allow the instrument to stabilize and verify
the accuracy of the temperaturereading.
Controller locked up. The controllermay have locked up due to a power surge or
other aberration.Initialize the system by performing the Factory Reset Sequence.
Factory Reset Sequence. Hold the SET and EXIT buttons down atthe same time
while powering up the instrument.The instrument displays shows ‘-init-‘, the model
number, and the firmwareversion. Each of the controller parameters and calibration
constants must be reprogrammed.The values can be found on the Report of
Calibration.
The instrument
heats or cools too
quickly or too
slowly
Incorrect scan and scan rate settings. The scan and scan rate settingsmay be
set to unwanted values. Check the Scan and Scan Ratesettings. The scan may be
off (if the unitseems to be responding too quickly). The scan may be on with the
Scan Rate set low (if unitseems to be responding too slowly).
Improper line voltage.Verify that the voltage reading in the bottom of the unit
matches the source voltage.
Unstable display Wait. Allow the instrument to stabilize for a few minutes.
Proportional band may be incorrect.Refer to the proportional band on the Report
of Calibration.
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12 Troubleshooting
Troubleshooting Problems, Possible Causes, and
Solutions