Int-Pip5 External Noise On Twinaxial Cables - IBM iSeries Series Hardware Problem Analysis And Isolation

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?
v Yes: Determine if lightning protection devices are installed on the incoming ac voltage lines where
they enter the building. There must be a dedicated ground wire from the lightning protection devices
to earth ground.
Are lightning protection devices installed?
– Yes: Continue with the next step.
– No: Lightning may have caused the intermittent problem. Recommend that the customer install
lightning protection devices to prevent this problem from recurring.
This ends the procedure.
v No: Continue with the next step.
2. Have an installation planning representative perform the following:
a. Connect a recording ac voltage monitor to the incoming AC voltage lines of the units that contain
the failing devices with reference to ground.
b. Set the voltage monitor to start recording at a voltage slightly higher than the normal incoming ac
voltage.
Does the system fail again with the same symptoms?
v Yes: Look at the recording and see if the voltage monitor recorded any noise when the failure
occurred.
Did the monitor record any noise when the failure occurred?
– Yes: Review with the customer what was happening external to the system when the failure
occurred. This may help you to determine the source of the noise. Discuss with the customer
what to do to remove the noise or to prevent it from affecting the iSeries server.
This ends the procedure.
– No: Perform the next INT-PIP listed in the INT-PIP column.
This ends the procedure.
v No: This ends the procedure.
INT-PIP5 External noise on twinaxial cables: For use by authorized service providers.
DANGER
To prevent a possible electrical shock when adding or removing any devices to or from the system, ensure
that the power cords for those devices are unplugged before the signal cables are connected or
disconnected. If possible, disconnect all power cords from the existing system before you add or remove a
device. (RSFTD203)
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)
Electrical noise on twinaxial cables that are not installed correctly may affect the twinaxial workstation I/O
processor card. Examples of this include open shields on twinaxial cables, and station protectors that are
not being installed where necessary.
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