While error 104 may be indicative of a repairable issue on the 5xxA calibrator family, environmental conditions can also cause the error. These conditions are:
Inconsistent line power (either too high or too low).
Extremely low humidity
If the power varies from the power setting currently selected here:
And while the spec is 10%, getting even close to that variance may cause a problem. If power seems problematic, try using a very stable UPS.
Check the lab's ambient humidity. The recommendation is:
Improper grounding of the incoming power line is another source. Follow the grounding guidelines in the operator's manual:
Monitor line power and lab humidity when the trip occurs, and check grounding.
If the problem persists, determine if a certain output setting or a certain model of Device Under Test ccauses the issue repeatably. Test more than one DUT model at more than one allowble setting. If it seems to occur often and environmental issues or DUT issues have been ruled out, run a self test on your instrument.
Record any error messages that occur and contact email@example.com.