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Product Description
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Removal & Replacement
TROUBLESHOOTING
Clearing CMOS
Power-On Self Test (POST)
Power-On Self
Test (POST)
Configuration
POST is a series of diagnostic tests that run automatically when the system is turned on. After the
Diagnostic error
computer is turned on, POST checks the following assemblies to ensure that the computer system is
codes
properly functioning:
Troubleshooting
without
diagnostics
POST also detects the type of mass storage devices installed in the computer.
If POST finds an error in the system, an error condition is indicated by an audible and/or visual
message. The table below gives explanations of the error codes and a recommended course of action.
Click a link below to find the probable cause and recommended action for a given error message.
Diskette Drive A or B Error
Extended RAM failed at
offset nnn
Failing Bits nnn
Fixed Disk 0 or 1 Failure
Fixed Disk Controller Failure
Incorrect Drive A Type
Invalid NVRAM Media Type
Error message
Diskette Drive A or
B Error
Extended RAM
failed at offset nnn
Failing Bits nnn
Fixed Disk 0 or 1
Failure
Fixed Disk
Controller Failure
Incorrect Drive A
Type
Invalid NVRAM
Media Type
Keyboard Controller
Error
Keyboard Error
Operating System
Not Found
Parity Check 1
Parity Check 2
Real Time Clock
Error
System Battery is
Dead
System BIOS
Shadowed
System Cache Error
System CMOS
Checksum Bad
System RAM Failed
at Offset, nnn
System Timer Error
UMB Upper Limit
Segment Address
nnn
Video BIOS
Shadowed
Maintenance and Service Guide
Compaq Presario 7300 Series Computers
Keyboard
System board
Memory modules
Video memory
Diskette drives
Hard drive
Power supply
NOTE:
An external speaker must be installed into the speaker output connector to
hear audible beeps during POST.
Drive A: or B: is present, but fails the
BIOS POST diskette tests
Extended memory not working or not
configured properly
nnn is a map of the bits at the RAM
address which failed the memory test
Hard drive is not working or not
configured properly
Hard drive is not working or not
configured properly
Type of diskette in drive A: not
correctly identified
Problem with NVRAM (CMOS) access
Keyboard, I/O keyboard controller (on
system board), or mouse error
Keyboard, I/O keyboard controller (on
system board), or mouse error
Operating system cannot be located on
either drive A: or C:
Parity error found in the system bus
Parity error found in the I/O bus
Real-time clock fails BIOS test
RTC battery is dead
System BIOS copied to Shadow RAM
RAM cache failed the BIOS test
CMOS is corrupted or modified
incorrectly
System RAM failed
DMA, timers, etc.
Displays the address nnn of the upper
limit of Upper Memory Blocks,
indicating released segments of the
BIOS
Video BIOS successfully copied to
shadow RAM
Troubleshooting
Jumper & Switch Information
Keyboard Controller Error
Keyboard Error
Operating System Not
Found
Parity Check 1
Parity Check 2
Real Time Clock Error
System Battery is Dead
POST Messages
Probable Cause
Illustrated Parts Catalog
Specifications
System BIOS Shadowed
System Cache Error
System CMOS Checksum Bad
System RAM Failed at Offset, nnn
System Timer Error
UMB Upper Limit Segment
Address nnn
Video BIOS Shadowed
Recommended Action
1. Run Setup.
2. Replace the signal cables.
3. Replace the drive.
1. Replace the
memory
2. Replace the
system
board.
1. Run Setup.
2. Replace the
system
board.
1. Run Setup.
2. Replace the signal cable.
3. Replace the hard drive.
1. Run Setup.
2. Replace the
system
board.
1. Run Setup.
2. Replace the
diskette
drive.
Replace the
system
board.
1. Replace the keyboard.
2. Replace the mouse.
3. Replace the
system
board.
1. Replace the keyboard.
2. Replace the mouse.
3. Replace the
system
board.
Run Setup.
1. Run Setup.
2. Replace the
memory
3. Replace the
system
board.
1. Run Setup.
2. Replace the
ISA board
Replace the
system
board.
1. Replace the
RTC
battery.
2. Run Setup.
Status message. No action required.
Run Setup.
Run Setup.
Replace
memory
modules.
Replace the
system
board.
Status message. No action required.
Status message. No action required.
modules.
modules.
(modem).
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Troubleshooting
