Chapter 4 91
3-2-1-1 90h Initialize hard disk
controller.
• Check the HDD.
• Check the floppy disk drive(s).
• Check the main board.
3-2-1-2 91h Initialize local bus hard
disk controller.
• Check the HDD.
• Check the floppy disk drive(s).
• Check the main board.
3-2-1-3 92h Jump to UserPatch2. • Check the main board.
3-2-2-1 94h Disable A20 address line. • Check the keyboard.
• Check keyboard controller.
• Check the main board.
3-2-2-3 96h Clear huge ES segment
register.
• Check the main board.
3-2-3-1 98h Search for option ROMs. • Check the main board.
3-2-3-3 9Ah Shadow for option
ROMs.
• Check the expansion cards.
• Check the system memory.
• Check the main board.
3-2-4-1 9Ch Set up Power
Management.
• Check the main board.
3-2-4-3 9Eh Enable hardware
interrupts.
• Treat as an expansion card problem.
• Check the main board.
3-3-1-1 A0h Set time of day. • Check the main board.
3-3-1-3 A2h Check key lock. • Unlock the key lock if it is locked.
• Investigate possible problem with
the key lock switch. If it is either
unlocked already or not present on
the system case.
• Check the main board.
3-3-3-1 A8h Erase F2 prompt. • Check the video card.
• Check the main board.
3-3-3-3 AAh Scan for F2 key stroke. • Check the main board.
3-3-4-1 ACh Enter SETUP. • Check the main board.
3-3-4-3 AEh Clear in-POST flag. • Check the main board.
3-4-1-1 B0h Check for errors. • Check the main board.
3-4-1-3 B2h POST done - prepare to
boot operating system.
• Check the main board.
3-4-2-1 B4h One beep. • Check the main board.
3-4-2-3 B6h Check password
(optional).
• Check the main board.
3-4-3-1 B8h Clear global descriptor
table.
• Check the main board.
3-4-4-1 BCh Clear parity checkers. • Check the main board.
3-4-4-3 BEh Clear screen (optional). • Check the video card.
• Check the main board.
3-4-4-4 BFh Check virus and backup
reminders.
• Check the main board.
Beep Code Post Code Description What to Check (Recommended)
