IBM i 830, Repair Manual

Page: 346 / 1000

Intermittent Problem Isolation Procedures
Introduction
These intermittent problem isolation procedures instruct you to perform
procedures to help you correct an intermittent problem.
Use these procedures only if problem analysis steps or tables sent you here.
Perform only the procedures that apply to your system.
Read all safety procedures before servicing the system. Observe all safety
procedures when performing a procedure. Unless instructed otherwise, always
power off the system or expansion tower where the FRU is located, (see “Powering
On and Powering Off the System and Logical Partitions” on page 922) before
removing, exchanging, or installing a field-replaceable unit (FRU).
DANGER
To prevent power from switching on automatically during service procedures,
select manual or secure mode on the system unit control panel or disconnect
the cables that connect to J15 and J16 on the frame being serviced.
(RSFTD211)
INT-PIP3 External Noise on AC Voltage Lines
Electrical noise on incoming AC voltage lines can cause various system failures.
The most common source of electrical noise is lightning.
DANGER
To prevent a possible electrical shock during an electrical storm, do not
connect or disconnect cables or station protectors for communications lines,
display stations, printers, or telephones. (RSFTD003)
1. Ask the customer if an electrical storm was occurring at the time of the failure.
This determines if lightning could have caused the failure.
Could lightning have caused the failure?
Yes No
↓
Go to step 3 of this procedure.
2.
Determine if lightning protection devices are installed on the incoming AC
voltage lines where they enter the building.
Note: There must be a dedicated ground wire from the lightning protection
devices to earth ground.
Are lightning protection devices installed?
Yes No
↓
Lightning may have caused the intermittent problem. Recommend that
the customer install lightning protection devices to prevent this
problem from occurring again.
This ends the procedure.
3.
An installation planning representative should perform this step.
a. Get a recording AC voltage monitor. Connect it to the incoming AC voltage
lines of the units that contain the failing devices with reference to ground.
Intermittent PIPs
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iSeries Model 830, 840, SB2, and SB3 Problem Analysis, Repair and Parts V5R1