Appendix B: Maintenance
18
CDM250 User Manual
Troubleshooting
Electronic maintenance on the CDM250 must be performed by a
trained technician. However, any operator can perform some basic
and routine maintenance. The CDM250 will give some indications
of problems to aid the operator.
No Display with Power On
If the LED Display is not lighted, but the POWER button is pushed
in and the CDM250 Digital Multimeter power cord is plugged into
an outlet, do the following steps:
WARNING.
To prevent electrical shock, unplug the power cord and
disconnect the test leads from any voltage source before checking or
replacing the fuses.
1. Check the line fuse. If the fuse is open, replace it.
2. If the line fuse is good, check the power outlet for proper voltage.
If the outlet voltage is incorrect, call service personnel.
3. If outlet voltage is correct, check power cord continuity. If the
power cord fails the continuity check, replace the power cord.
CDM250 Does Not Read Current (2A)
Check the function fuse. If the fuse is open, replace it.
Display On but CDM250 Not Displaying Reading
1. Check that the function and range button selections are correct.
2. If function and range buttons are correct, check that the test leads
are connected properly.
3. If the test leads are connected properly, check the test leads for
continuity. If a test lead fails the continuity check, replace the test
lead.
