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Computer POST / beep codes

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POST ABCs

The computer POST (Power On Self Test) tests the computer, insuring that it meets the necessary system requirements and that all hardware is working properly before starting the remainder of the boot process. If the computer passes the POST the computer will have a single beep (with some computer BIOS manufacturers it may beep twice) as the computer starts and the computer will continue to start normally. However, if the computer fails the POST, the computer will either not beep at all or will generate a beep code, which tells the user the source of the problem.

The steps of a POST

Each time the computer boots up the computer must past the POST. Below is the common steps a POST performs each time your computer starts.

  1. Test the power supply to ensure that it is turned on and that it releases its reset signal.
  2. CPU must exit the reset status mode and thereafter be able to execute instructions.
  3. BIOS checksum must be valid, meaning that it must be readable.
  4. CMOS checksum must be valid, meaning that it must be readable.
  5. CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
  6. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
  7. I/O bus / controller must be accessible.
  8. I/O bus must be able to write / read from the video subsystem and be able to read all video RAM.

If the computer does not pass any of the above tests, your computer will receive an irregular POST. An irregular POST is a beep code that is different from the standard one or two beeps. This could be either no beeps at all or a combination of different beeps indicating what is causing the computer not to past the POST.

If you're receiving an irregular POST document CH000607 contains all the steps a user can do to resolve the issue or help determine what hardware has failed in the computer so it can be replaced. If you're getting a beep code the remainder of this page contains a listing of each of the major manufacturers beep codes and what they each mean.

Index

Category:
BIOS

Companies:
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Related Pages:
AMI BIOS
Phoenix BIOS

Resolved

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AMI BIOS beep codes

Below are the AMI BIOS Beep codes that can occur. However, because of the wide variety of different computer manufacturers with this BIOS, the beep codes may vary.

Beep CodeDescriptionsDocument
1 shortDRAM refresh failureCH000996
2 shortParity circuit failureCH000607
3 shortBase 64K RAM failureCH000996
4 shortSystem timer failureCH000607
5 shortProcess failureCH000607
6 shortKeyboard controller Gate A20 errorCH000383
7 shortVirtual mode exception errorCH000607
8 shortDisplay memory Read/Write test failureCH000607
9 shortROM BIOS checksum failureCH000607
10 shortCMOS shutdown Read/Write errorCH000239
11 shortCache Memory errorCH000607
1 long, 3 shortConventional/Extended memory failureCH000996
1 long, 8 shortDisplay/Retrace test failedCH000607

AWARD BIOS beep codes

Below are Award BIOS Beep codes that can occur. However, because of the wide variety of different computer manufacturers with this BIOS, the beep codes may vary.

Beep CodeDescriptionDocument
1 long, 2 shortIndicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional informationCH000607
Any other beep(s)RAM problem.CH000996

If any other correctable hardware issues, the BIOS will display a message.

IBM BIOS beep codes

Below are IBM BIOS Beep codes that can occur. However, because of the wide variety of models shipping with this BIOS, the beep codes may vary.

Beep CodeDescriptionDocument
No BeepsNo Power, Loose Card, or Short.CH000312
1 Short BeepNormal POST, computer is ok.No problem
2 Short BeepPOST error, review screen for error code.See screen
Continuous BeepNo Power, Loose Card, or Short.CH000607
Repeating Short BeepNo Power, Loose Card, or Short.CH000607
One Long and one Short BeepMotherboard issue.CH000607
One Long and Two Short BeepsVideo (Mono/CGA Display Circuitry) issue.CH000607
One Long and Three Short Beeps.Video (EGA) Display Circuitry.CH000607
Three Long BeepsKeyboard / Keyboard card error.CH000304
One Beep, Blank or Incorrect DisplayVideo Display Circuitry.CH000607

Macintosh startup tones

TonesError
Error Tone. (two sets of different tones)Problem with logic board or SCSI bus.
Startup tone, drive spins, no videoProblem with video controller.
Powers on, no tone.Logic board problem.
High Tone, four higher tones.Problem with SIMM.

Phoenix BIOS beep codes

Below are the beep codes for PHOENIX BIOS Q3.07 OR 4.X

Beep CodeDescription / What to Check
1-1-1-3Verify Real Mode.
1-1-2-1Get CPU type.
1-1-2-3Initialize system hardware.
1-1-3-1Initialize chipset registers with initial POST values.
1-1-3-2Set in POST flag.
1-1-3-3Initialize CPU registers.
1-1-4-1Initialize cache to initial POST values.
1-1-4-3Initialize I/O.
1-2-1-1Initialize Power Management.
1-2-1-2Load alternate registers with initial POST values.
1-2-1-3Jump to UserPatch0.
1-2-2-1Initialize keyboard controller.
1-2-2-3BIOS ROM checksum.
1-2-3-18254 timer initialization.
1-2-3-38237 DMA controller initialization.
1-2-4-1Reset Programmable Interrupt Controller.
1-3-1-1Test DRAM refresh.
1-3-1-3Test 8742 Keyboard Controller.
1-3-2-1Set ES segment to register to 4 GB.
1-3-3-128 Autosize DRAM.
1-3-3-3Clear 512K base RAM.
1-3-4-1Test 512 base address lines.
1-3-4-3Test 512K base memory.
1-4-1-3Test CPU bus-clock frequency.
1-4-2-4Reinitialize the chipset.
1-4-3-1Shadow system BIOS ROM.
1-4-3-2Reinitialize the cache.
1-4-3-3Autosize cache.
1-4-4-1Configure advanced chipset registers.
1-4-4-2Load alternate registers with CMOS values.
2-1-1-1Set Initial CPU speed.
2-1-1-3Initialize interrupt vectors.
2-1-2-1Initialize BIOS interrupts.
2-1-2-3Check ROM copyright notice.
2-1-2-4Initialize manager for PCI Options ROMs.
2-1-3-1Check video configuration against CMOS.
2-1-3-2Initialize PCI bus and devices.
2-1-3-3Initialize all video adapters in system.
2-1-4-1Shadow video BIOS ROM.
2-1-4-3Display copyright notice.
2-2-1-1Display CPU type and speed.
2-2-1-3Test keyboard.
2-2-2-1Set key click if enabled.
2-2-2-356 Enable keyboard.
2-2-3-1Test for unexpected interrupts.
2-2-3-3Display prompt Press F2 to enter SETUP.
2-2-4-1Test RAM between 512 and 640k.
2-3-1-1Test expanded memory.
2-3-1-3Test extended memory address lines.
2-3-2-1Jump to UserPatch1.
2-3-2-3Configure advanced cache registers.
2-3-3-1Enable external and CPU caches.
2-3-3-3Display external cache size.
2-3-4-1Display shadow message.
2-3-4-3Display non-disposable segments.
2-4-1-1Display error messages.
2-4-1-3Check for configuration errors.
2-4-2-1Test real-time clock.
2-4-2-3Check for keyboard errors
2-4-4-1Set up hardware interrupts vectors.
2-4-4-3Test coprocessor if present.
3-1-1-1Disable onboard I/O ports.
3-1-1-3Detect and install external RS232 ports.
3-1-2-1Detect and install external parallel ports.
3-1-2-3Re-initialize onboard I/O ports.
3-1-3-1Initialize BIOS Data Area.
3-1-3-3Initialize Extended BIOS Data Area.
3-1-4-1Initialize floppy controller.
3-2-1-1Initialize hard-disk controller.
3-2-1-2Initialize local-bus hard-disk controller.
3-2-1-3Jump to UserPatch2.
3-2-2-1Disable A20 address line.
3-2-2-3Clear huge ES segment register.
3-2-3-1Search for option ROMs.
3-2-3-3Shadow option ROMs.
3-2-4-1Set up Power Management.
3-2-4-3Enable hardware interrupts.
3-3-1-1Set time of day.
3-3-1-3Check key lock.
3-3-3-1Erase F2 prompt.
3-3-3-3Scan for F2 key stroke.
3-3-4-1Enter SETUP.
3-3-4-3Clear in-POST flag.
3-4-1-1Check for errors
3-4-1-3POST done--prepare to boot operating system.
3-4-2-1One beep.
3-4-2-3Check password (optional).
3-4-3-1Clear global descriptor table.
3-4-4-1Clear parity checkers.
3-4-4-3Clear screen (optional).
3-4-4-4Check virus and backup reminders.
4-1-1-1Try to boot with INT 19.
4-2-1-1Interrupt handler error.
4-2-1-3Unknown interrupt error.
4-2-2-1Pending interrupt error.
4-2-2-3Initialize option ROM error.
4-2-3-1Shutdown error.
4-2-3-3Extended Block Move.
4-2-4-1Shutdown 10 error.
4-3-1-3Initialize the chipset.
4-3-1-4Initialize refresh counter.
4-3-2-1Check for Forced Flash.
4-3-2-2Check HW status of ROM.
4-3-2-3BIOS ROM is OK.
4-3-2-4Do a complete RAM test.
4-3-3-1Do OEM initialization.
4-3-3-2Initialize interrupt controller.
4-3-3-3Read in bootstrap code.
4-3-3-4Initialize all vectors.
4-3-4-1Boot the Flash program.
4-3-4-2Initialize the boot device.
4-3-4-3Boot code was read OK.

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