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Chapter 10. SSA Problem Determination Procedures
Problem determination procedures are provided by power-on self-tests (POSTs),
service request numbers (SRNs), and maintenance analysis procedures (MAPs).
Some of these procedures use the using system service aids that are described in
“Introduction to Service Aids” on page 7-3.
Disk Drive Module Power-On Self-Tests (POSTs)
Attention: Disk drive modules are fragile. Handle them with care. Follow all
ESD-sensitive (electro-static discharge) parts procedures when handling disk drive
modules. For ESD information, see “Handling Static-Sensitive Devices” on page 5-3.
The disk drive module POSTs start each time the module is switched on or when a
Send Diagnostic command is received from the SSA adapter. They check whether
the disk drive module is working correctly. The POSTs also help verify a repair after
a FRU has been exchanged.
There are two power-on self-tests: POST-1 and POST-2.
POST-1 runs immediately after the ‘power-on reset’ line goes inactive and before the
disk drive module motor starts. POST-1 includes tests of the:
Microprocessor
ROM
Safety circuits
If POST-1 completes successfully, POST-2 is enabled.
If POST-1 fails, the disk drive module check light stays on, and the disk drive module
is not configured into the SSA network.
POST-2 runs after the disk drive module motor has started. POST-2 includes tests
of:
Motor control
Servo control
Read and write on the diagnostic cylinder (repeated for all heads)
Error checking and correction (ECC)
If POST-2 completes successfully, the disk drive module is ready for use by the
using system.
Chapter 10. SSA Problem Determination Procedures 10-1