Computer POST and Beep Codes
The computer POST (power-on self-test) checks a computer's internal hardware for compatibility and connection before starting the remainder of the boot process.
If the computer passes the POST, the computer may give a single beep (some computers may beep twice) as it starts and continue to boot. However, if the computer fails the POST, the computer will either not beep or generate a beep code that tells the user the source of the problem.
If the computer passes the POST, the computer may give a single beep (some computers may beep twice) as it starts and continue to boot. However, if the computer fails the POST, the computer will either not beep or generate a beep code that tells the user the source of the problem.
Contents
Macintosh
| Tones | Error |
|---|---|
| Error tone (two sets of different tones) | Problem with logic board or SCSI bus |
| Startup tone, drive spins, no video | Problem with video controller |
| Powers on, no tone | Logic board problem |
| High tone, four higher tones | Problem with SIMM |
Award BIOS
| Beeps | Error |
|---|---|
| 1 long, 2 short | Video error, the BIOS cannot initialize the video screen |
| 1 long, 3 short | Video card not detected or bad video card |
| Beeps repeating endlessly | RAM problem |
| High frequency beeps while running | Overheating processor |
| Alternating high & low frequency | Issue with the processor, possibly damaged |
Phoenix BIOS
| Beeps | Error |
|---|---|
| 1-1-1-1 | Unconfirmed (reset RAM or replace RAM) |
| 1-1-1-3 | Verify real mode |
| 1-1-2-1 | Get CPU type |
| 1-1-2-3 | Initialize system hardware |
| 1-1-3-1 | Initialize chipset registers with initial POST values |
| 1-1-3-2 | Set in POST flag |
| 1-1-3-3 | Initialize CPU registers |
| 1-1-4-1 | Initialize cache to initial POST values |
| 1-1-4-3 | Initialize I/O |
| 1-2-1-1 | Initialize power management |
| 1-2-1-2 | Load alternate registers with initial POST values |
| 1-2-1-3 | Jump to UserPatch0 |
| 1-2-2-1 | Initialize keyboard controller |
| 1-2-2-3 | BIOS ROM checksum |
| 1-2-3-1 | 8254 timer initialization |
| 1-2-3-3 | 8237 DMA controller initialization |
| 1-2-4-1 | Reset programmable interrupt controller |
| 1-3-1-1 | Test DRAM refresh |
| 1-3-1-3 | Test 8742 keyboard controller |
| 1-3-2-1 | Set ES segment to register to 4 GB |
| 1-3-3-1 | Autosize DRAM |
| 1-3-3-3 | Clear 512 K base RAM |
| 1-3-4-1 | Test 512 base address lines |
| 1-3-4-3 | Test 512 K base memory |
| 1-4-1-3 | Test CPU bus clock frequency |
| 1-4-2-4 | Reinitialize the chipset |
| 1-4-3-1 | Shadow system BIOS ROM |
| 1-4-3-2 | Reinitialize the cache |
| 1-4-3-3 | Autosize cache |
| 1-4-4-1 | Configure advanced chipset registers |
| 1-4-4-2 | Load alternate registers with CMOS values |
| 2-1-1-1 | Set initial CPU speed |
| 2-1-1-3 | Initialize interrupt vectors |
| 2-1-2-1 | Initialize BIOS interrupts |
| 2-1-2-3 | Check ROM Copyright notice |
| 2-1-2-4 | Initialize manager for PCI options ROMs |
| 2-1-3-1 | Check video configuration against CMOS |
| 2-1-3-2 | Initialize PCI bus and devices |
| 2-1-3-3 | Initialize all video adapters in system |
| 2-1-4-1 | Shadow video BIOS ROM |
| 2-1-4-3 | Display Copyright notice |
| 2-2-1-1 | Display CPU type and speed |
| 2-2-1-3 | Test keyboard |
| 2-2-2-1 | Set key click if enabled |
| 2-2-2-3 | Enable keyboard |
| 2-2-3-1 | Test for unexpected interrupts |
| 2-2-3-3 | Display prompt Press F2 to enter SETUP |
| 2-2-4-1 | Test RAM between 512 and 640 k |
| 2-3-1-1 | Test expanded memory |
| 2-3-1-3 | Test extended memory address lines |
| 2-3-2-1 | Jump to UserPatch1 |
| 2-3-2-3 | Configure advanced cache registers |
| 2-3-3-1 | Enable external and CPU caches |
| 2-3-3-3 | Display external cache size |
| 2-3-4-1 | Display shadow message |
| 2-3-4-3 | Display non-disposable segments |
| 2-4-1-1 | Display error messages |
| 2-4-1-3 | Check for configuration errors |
| 2-4-2-1 | Test real-time clock |
| 2-4-2-3 | Check for keyboard errors |
| 2-4-4-1 | Set up hardware interrupts vectors |
| 2-4-4-3 | Test coprocessor if present |
| 3-1-1-1 | Disable onboard I/O ports |
| 3-1-1-3 | Detect and install external RS232 ports |
| 3-1-2-1 | Detect and install external parallel ports |
| 3-1-2-3 | Re-initialize onboard I/O ports |
| 3-1-3-1 | Initialize BIOS data area |
| 3-1-3-3 | Initialize extended BIOS data area |
| 3-1-4-1 | Initialize floppy controller |
| 3-2-1-1 | Initialize hard disk controller |
| 3-2-1-2 | Initialize local bus hard disk controller |
| 3-2-1-3 | Jump to UserPatch2 |
| 3-2-2-1 | Disable A20 address line |
| 3-2-2-3 | Clear huge ES segment register |
| 3-2-3-1 | Search for option ROMs |
| 3-2-3-3 | Shadow option ROMs |
| 3-2-4-1 | Set up Power Management |
| 3-2-4-3 | Enable hardware interrupts |
| 3-3-1-1 | Set time of day |
| 3-3-1-3 | Check key lock |
| 3-3-3-1 | Erase F2 prompt |
| 3-3-3-3 | Scan for F2 key stroke |
| 3-3-4-1 | Enter CMOS setup |
| 3-3-4-3 | Clear in POST flag |
| 3-4-1-1 | Check for errors |
| 3-4-1-3 | POST done, prepare to boot operating system |
| 3-4-2-1 | One beep |
| 3-4-2-3 | Check password (optional) |
| 3-4-3-1 | Clear global descriptor table |
| 3-4-4-1 | Clear parity checkers |
| 3-4-4-3 | Clear screen (optional) |
| 3-4-4-4 | Check virus and backup reminders |
| 4-1-1-1 | Try to boot with INT 19 |
| 4-2-1-1 | Interrupt handler error |
| 4-2-1-3 | Unknown interrupt error |
| 4-2-2-1 | Pending interrupt error |
| 4-2-2-3 | Initialize option ROM error |
| 4-2-3-1 | Shutdown error |
| 4-2-3-3 | Extended block move |
| 4-2-4-1 | Shutdown 10 error |
| 4-3-1-3 | Initialize the chipset |
| 4-3-1-4 | Initialize refresh counter |
| 4-3-2-1 | Check for forced flash |
| 4-3-2-2 | Check HW status of ROM |
| 4-3-2-3 | BIOS ROM is OK |
| 4-3-2-4 | Do a complete RAM test |
| 4-3-3-1 | Do OEM initialization |
| 4-3-3-2 | Initialize interrupt controller |
| 4-3-3-3 | Read in bootstrap code |
| 4-3-3-4 | Initialize all vectors |
| 4-3-4-1 | Boot the flash program |
| 4-3-4-2 | Initialize the boot device |
| 4-3-4-3 | Boot code was read OK |
| two-tone siren | Low CPU speed, voltage level issue |
AMI BIOS
| Beeps | Error |
|---|---|
| 1 short | DRAM refresh failure |
| 2 short | Parity circuit failure |
| 3 short | Base 64 K RAM failure |
| 4 short | System timer failure |
| 5 short | Process failure |
| 6 short | Keyboard controller Gate A20 error |
| 7 short | Virtual mode exception error |
| 8 short | Display memory Read/Write test failure |
| 9 short | ROM BIOS checksum failure |
| 10 short | CMOS shutdown Read/Write error |
| 11 short | Cache memory error |
| 1 long 3 short | Conventional/Extended memory failure |
| 1 long 8 short | Display/Retrace test failed |
| two-tone siren | Low CPU fan speed / voltage level issue |
IBM BIOS
| Beeps | Error |
|---|---|
| No beeps | No power, loose card, or short |
| 1 short beep | Normal POST, computer is ok |
| 2 short beep | POST error, review screen for error code |
| Continuous beep | No power, loose card, or short |
| Repeating short beep | No power, loose card, or short |
| 1 long and 1 short beep | Motherboard issue |
| 1 long and 2 short beeps | Video (Mono/CGA display circuitry) issue |
| 1 long and 3 short beeps | Video (EGA) display circuitry |
| 3 long beeps | Keyboard or keyboard card error |
| 1 beep, blank or incorrect display | Video display circuitry |
Dell BIOS
| Beeps | Error |
|---|---|
| 1 beep | ROM corruption or failure |
| 2 beeps | Memory (RAM) not detected |
| 3 beeps | Motherboard failure |
| 4 beeps | Memory (RAM) failure |
| 5 beeps | CMOS battery failure |
| 6 beeps | Video card failure |
| 7 beeps | Bad processor (CPU) |
{{ 'Comments (%count%)' | trans {count:count} }}
{{ 'Comments are closed.' | trans }}