Zeiss humphrey HFA II-i series Field Service Manual page 156

Troubleshooting
Solving Intermittent Non-Duplicable Failures:
These failures present the greatest difficulty to the Field Service Engineer. The most effective
means for resolving these types of problems requires careful thought and the utilization of all
available resources that the Field Service Engineer possesses.
It is important that before replacing an assembly, good solid rationale for its replacement be
developed and a backup plan devised in case replacement of the assembly does not affect
the symptom. It is best NOT to replace any hardware until solid rationale for replacement is
clearly evident.
Once an assembly is replaced by a Field Service Engineer, the customer's expectations are
set for a hardware resolution to the problem. This can prove to be a handicap. A good
sequence to follow for resolving intermittent non-duplicable problems is:
1) Analyze the service history in detail. Look for trends or the possibility of a
previous repair inducing the problem.
2) Query the operator(s) at length for any other clues such as:
P Times of failures;
P More failures with certain operators.
3) Watch the operator set up and use the instrument.
4) Check all Field Service Bulletins.
5) Contact other Field Service Engineers involved in previous repairs.
6) Look at the operating environment ­ static, power, grounding, temperature or rate
of temperature change, humidity, etc.
7) Contact your Technical Support Specialists.
8) Keep a record of everything you've done to solve the problem.
9) Document the customer service report. Record what you feel should happen if
the problem returns. This will help a different Field Service Engineer in the
resolution of the problem.
10) Give the customer a thorough update on the situation.
11) Educate the customer on logging pertinent information that may benefit a Field
Service Engineer should the problem return. Often, engaging the customer in the
pursuit of a solution emphasizes the difficulty of the situation. In some instances,
the customer may welcome the feeling of being involved in resolution of the
problem.
Field Service Guide
Humphrey Field Analyzer II - i
Confidential and Proprietary
5 - 6 52235C1105