About intermittent problems

An intermittent problem can show many different symptoms, so it might be difficult for you to determine the real cause without completely analyzing the failure.

To help with this analysis, you should determine as many symptoms as possible.

The complete reference code is necessary to determine the exact failing area and the probable cause.
Product Activity Log (PAL) information can provide time and device relationships.
Information about environmental conditions when the failure occurred can be helpful (for example, an electrical storm occurring when the failure happened).

Note: If you suspect that an intermittent problem is occurring, increase the log sizes to the largest sizes possible. Select the PAL option on the Start a Service Tool display (see Product Activity Log for details).

Types of intermittent problems

Following are the major types of intermittent problems:

Code (PTFs):
- Licensed internal code
- i5/OS®
- Licensed program products
- Other application software
Configuration:
- Non-supported hardware that is used on the system
- Non-supported system configurations
- Non-supported communication networks
- Model and feature upgrades that are not performed correctly
- Incorrectly configured or incorrectly cabled devices
Environment:
- Power line disturbance (for example, reduced voltage, a pulse, a surge, or total loss of voltage on the incoming ac voltage line)
- Power line transient (for example, lightning strike)
- Electrical noise (constant or intermittent)
- Defective grounding or a ground potential difference
- Mechanical vibration
Intermittent hardware failure