The BIOS is the “Basic Input/Output System” of a computer. It is a piece of firmware that is saved on a tiny chip in the mainboard of almost every computer. The basic function of the BIOS is to enable communication between the operating system and the hardware components. Every time the system is started up, the BIOS runs a sort of self-test. This test is called the “POST”, which stands for “Power-On Self-Test”
If an error occurs during the POST, the BIOS emits a specific signal (a beep code) via the system loudspeakers to alert the user of a specific problem. How you open the BIOS depends on your computer – different manufacturers use different methods. The BIOS update procedure also varies depending on the manufacturer. Read on to find out what the most common computer beep codes mean.
| 1x short | No errors detected during the self-test |
|---|---|
| 2x short | Non-specified error; more details displayed on screen |
| Continuous beep | Memory or graphics card not detected |
| Repeated short beeps | Insufficient power supplied to the motherboard |
| 1x long | RAM error |
| 1x long, 1x short | Motherboard error |
| 1x long, 2x short | Graphics card error |
| 1x long, 3x short | Keyboard controller failure; graphics card error (in later BIOS versions) |
| 3x long | Communication error between keyboard and motherboard |
| 1x short | Incorrect interaction between RAM and motherboard |
|---|---|
| 1x long | No errors detected during the self-test |
| Continuous beep | Power supply error |
| 1x long, 1x short | Fault on motherboard |
| 1x long, 2x short | Graphics card not detected |
| 1x long, 3x short | Video memory error |
| 2x short | Parity error in the first 64 kB of memory |
| 2x long, 2x short | Video memory error |
| 3x short, 3x long, 3x short | Defective RAM; RAM must be replaced |
| 5x short | Problem with processor |
| 6x short | Cannot enter BIOS in safe mode |
| 7x short | Processor or graphics card error |
| 8x short | Display memory error in graphics card |
| 9x short | CMOS battery error |
| 10x short | Error in shutdown register of CMOS RAM |
| 11x short | Error in external cache memory |
| 1x short | No errors detected during the self-test |
|---|---|
| 2x short | Error during the POST; more details displayed on screen |
| No beep | Power supply/system board/processor error; often related to power supply |
| Continuous beep | Power supply/system board/keyboard problem |
| Repeated short beeps | Power supply or system board problem |
| 1x long, 1x short | System board problem |
| 1x long, 2x short | Graphics card problem (Mono/CGA video error) |
| 1x long, 3x short | Graphics card problem (EGA video error) |
| 3x long | Keyboard problem |
Dell beep codes are all the same length. You need to listen for how often a beep is repeated after a short pause. This is indicated by the figures and dashes in the following table. For example, “1 – 2” means “Beep – Beep Beep”. The beep codes in the table below are used by Dell-OptiPlex systems. Other Dell systems such as Inspiron or Vostro incorporate flashing LEDs to communicate error messages.
| 1 – 1 – 2 | Microprocessor register failure |
|---|---|
| 3 – 2 – 4 | Keyboard controller test failure |
| 3 – 3 – 1 | NVRAM power loss |
| 3 – 3 – 4 | Video memory test failure |
| 3 – 4 – 1 | Screen initialization failure |
| 4 – 2 – 2 | Shutdown failure |
| 4 – 4 – 4 | Cache test failure |
| One beep, repeating every 5 seconds | No RAM installed |
|---|---|
| 3x short, 5-second pause, 3x short | RAM did not pass data integrity check |
| 1x long while you hold down the power button | An EFI ROM update is in progress (only applicable to computers manufactured before 2012) |
| 3x long, 2x short, 3x long | EFI ROM error or Mac is in EFI ROM recovery mode |
MR systems use low and high beeps. These are shown in the table as “L” and “H” respectively.
| LH-LLL | BIOS failure (replacement may be required) |
|---|---|
| LH-HLL | DMA page register failure (possible board fault) |
| LH-LHL | Keyboard controller self-test failure |
| LH-HHL | RAM seated incorrectly (e.g. after replacement) |
| LH-LLH | Mainboard failure |
| LH-LLLL | Memory bank 0 pattern test failure |
| LH-LHLLH | CMOS RAM read/write test failure |
| LH-HHLLH | Real-time clock failure |
| LH-LLHLH | BIOS/RAM failure with graphics card, error in video card address line |
| LH-HLHLH | Keyboard controller failure |
| LH-LHHLH | RAM parity error |
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