IBM 7133 D40, Service Manual

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Controller Card Power-On Self-Tests (POSTs)
The controller card POSTs start each time power is switched on, or when a Reset
command is sent from the using-system SSA attachment. They check only the internal
components of the controller card; they do not check any interfaces to other FRUs.
If the POSTs complete successfully, control passes to the functional microcode of the
controller card. This microcode checks all the internal interfaces of the 7133, and
reports failures to the using system.
If the POSTs fail:
v
All the fans are set to full speed.
v
The Controller Card Check light and the 7133 Check light come on.
v
If the failure occurs at the 7133 power-on time, the bypass cards go into Automatic
mode (the default mode) unless they are jumpered for Forced Inline mode.
v
The functional operation of the 7133 is not affected. For example, the customer still
has access to all the disk drive modules.
v
The failure is reported:
– If the failure occurs at system bringup time, the using system detects that the
7133 is missing, and reports an error.
– If the failure occurs at any time other than system bringup time, the hourly health
check reports the failure.
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7133 Models D40 and T40 Service Guide