cmos signals. BIOS codes and beeps - deciphering the cause of the problem

Sooner or later for most users personal computers Problems may arise when, when you turn on the computer, it produces any sequence of signals other than one short one, which signals successful testing of all computer components. And this time we will look at a situation where the computer emits 1 short and 1 long signal when turned on, but nothing is displayed on the monitor.

Causes

As has been said many times, for each BIOS manufacturer the same sequence of signals can mean different things.

AWARD BIOS

If you have a BIOS from AWARD, then this sequence indicates that you have problems with RAM.

AMI BIOS

In AMI BIOS, one long and one short signal when turned on indicates a problem with the power supply.

How to eliminate 1 short 1 long BIOS signal when turning on?

In order not to bother with determining the BIOS manufacturer, the first thing to start solving this problem is to try to get RAM and install it back, preferably in another slot, after wiping the contacts with a stationery eraser.

One of possible reasons given sequence of signals - RAM

If the problem persists, try replacing the power supply with a known working one, borrowing it from friends or neighbors.

The power supply is one of the possible reasons for 1 short 1 long BIOS signal

If, after all the actions taken, the computer still emits 1 short and 1 long signal, then it is very likely that there are problems with the RAM board itself, the RAM connector on motherboard or the motherboard itself.

It often happens that even an experienced system administrator forgets BIOS codes and signals (especially since new motherboards are already equipped with UEFI), let alone a non-professional. And knowing the signals will help you quickly, and in everyday cases, often free of charge, solve the problem with a computer or laptop that won’t start.

This is what BIOS chips from AWARD AMI and Phoenix look like.

By the way, for reference: BIOS is Basic Input-Output system or in Russian speaking, a basic input-output system. In other words, this is a low-level program that is tightly built into the chip of your computer's motherboard. The BIOS loads when you turn on the computer and is responsible for initializing its hardware components, checking their functionality and startup correctly. Then, the bootloader program starts, launching operating system Windows, Linux or whatever you have installed there...

Here we need to make a small digression and tell you that the signals of this very BIOS may differ depending on the manufacturer. Let's look at the most popular options, there will be three of them - AMI BIOS, AWARD BIOS, Phoenix BIOS.

Below the cut is a table describing BIOS errors.

AMI BIOS beeps

In all versions of AMI BIOS, the successful completion of self-test is one short beep, after which the installed OS is loaded. I indicated other AMI BIOS sound signals in the table:

Sound signal	Description
2 short	RAM parity error
3 short	Protected sector error 64 KB RAM
4 short	Motherboard system timer malfunction
5 short	Malfunction central processor
6 short	Keyboard error
7 short	General motherboard failure
8 short	Video card memory failure
9 short	BIOS checksum error
10 short	Cannot write to CMOS
11 short	RAM error
1 long and 1 short	Power supply failure
1 long and 2 short	Video card error
1 long and 3 short	Video card error
1 long and 4 short	No video card, no video card found
1 long and 8 short
3 long
5 short and 1 long	No RAM
constant signal

AWARD BIOS beeps

With the correct post-test signal, everything is the same as in the previous version - one short AWARD BIOS beep means that everything is OK.

The remaining signals are slightly different - look at the table:

Sound signal	Description
1 short, repeating	Power supply failure
1repetitive, long
3 long	Keyboard error
1 long and 1 short	RAM fault
1 long and 2 short	Video card error
1 long and 3 short	Keyboard error
1 long and 9 short	ROM reading error
1 long and 8 short	Monitor not connected, problems with video card
3 long	Problems with RAM, memory test failed
constant signal	Problems with the power supply, PC overheating

Phoenix BIOS beeps

The third version of signals from Phoenix. BIOS from this manufacturer is becoming increasingly rare, but still.

Here it must be said that with him everything is not the same as with the previous two. Yes, yes, the guys decided to show off and do something different from everyone else; their signals are not double, but triple. In practice, this only means that, for example, a signal about problems with power supply to the video card will look like three short beeps, a pause, three short beeps, a pause, then 4 short beeps. In the table I will write them as 3-3-4. So, let's go...

Error codes from Phoenix:

Sound signal	Description
1 – 1 – 2	CPU error
1 – 1 – 3	CMOS write error, motherboard malfunction boards
1 – 1 – 4	Error in BIOS ROM checksum
1 – 2 – 1	Interrupt timer is faulty
1 – 2 – 2	DMA controller error
1–2 – 3	DMA controller read or write error
1 – 3 – 2	RAM error
1 – 3 – 3
1 – 3 – 4	RAM controller error
1 – 4 – 1	Address RAM error
1 – 4 – 2	RAM parity error
3 – 2 – 4	Error keyboards
3 – 3 – 1	Battery failure CMOS on the motherboard
3 – 3 – 4	Video card malfunction
3 – 4 – 1	Video card malfunction
4 – 2 – 1	System timer malfunction
4 – 2 – 2	CMOS error
4 – 2 – 3	Keyboard problem
4 – 2 – 4	CPU error
4 – 3 – 1	Error in RAM test
4 – 3 – 3	Timer error
4 – 3 – 4	Error in RTC operation
4 – 4 – 1	Serial port problem
4 – 4 – 2	Parallel port failure
4 – 4 – 3	Problems with the coprocessor

I would just like to add that in case of self-repair of a PC or laptop always disconnect it from the power supply and only then you can calmly climb inside, armed with a screwdriver and other necessary tools.

In the next article I will talk about UEFI. What is it, why did she come to us and other interesting points.

P.S. In some cases with memory errors, it helps to remove the memory sticks from the slots, wipe the contacts of the RAM boards with a regular soft eraser, and the memory is back in service! If the memory is not burned out but simply malfunctions, then you can also try swapping the boards with RAM in places across banks, provided that the memory itself that you are swapping is the same.

P.P.S. At the end of this article I simply post tables of codes for three BIOSes in the form of pictures. They can be used as a cheat sheet and saved to your phone, tablet or computer.

Cheat sheets describing BIOS signals for printing

It seems that I wrote everything I wanted to write. I tried clearly and without water, as always. If you have any questions, I answer in the comments.

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Let's look at what speaker signals are and what they notify.
Speaker - a small speaker placed on the base of the motherboard or, less commonly, displayed on the case system unit(connecting to the motherboard with two contacts of the plus - minus type. The speaker signals operation (One short signal when turned on) - malfunction (depending on which node is damaged.)

Let's look at the signals and meaning - for example, the 3 most common systemsBIOS: Award; AMI; Phoenix.

Award BIOS version

	Description of the error
2 short	Minor errors found. Check the reliability of the cables in the connectors hard drive and motherboard.
3 long	Keyboard controller error
1 short, 1 long	RAM error
1 long, 2 short	Video card error (graphics adapter)
1 long, 3 short	Video memory error
1 long, 9 short	Error reading from hard drive
Repeating short	Problems with the power supply;
Repeating long	Problems with RAM
Repeated high-low frequency	CPU problems
Continuous	Problems with the power supply

AMI BIOS version

Sequence of beeps	Description of the error
2 short	RAM parity error or you forgot to turn off the scanner or printer
3 short	Error in the first 64 KB of RAM
4 short	The system timer is faulty
5 short	Processor problems
6 short	Keyboard initialization error
7 short	Problems with the motherboard
8 short	Video memory error - cards
9 short	Incorrect BIOS checksum
10 short	CMOS write error
11 short	Error in the cache located on the motherboard
1 long, 1 short	Problems with the Power Supply
1 long, 2 short	Error (Mono-CGA)
1 long, 3 short	Error (EGA-VGA)
1 long, 4 short	Lack of video card
1 long, 8 short	Problems with the card or the Monitor is not connected
3 long	RAM - Read/Write test completed with error. Reinstall the memory or replace it with a working module.
Missing and blank screen	The processor is faulty. Possibly bent (contact leg broken).
Continuous beep	The power supply is faulty or the computer is overheating

Phoenix version BIOS

Beep codes are represented by a sequence of beeps. For example, 1-1-2 means 1 beep, pause, 1 beep, pause, and 2 beeps.

Sequence of beeps	Description of the error
	Error during processor test. The processor is faulty. Replace the processor
	Error writing/reading data to/from CMOS memory.
	An error was detected while calculating the checksum of the BIOS contents.
	Motherboard initialization error
1-2-2 or 1-2-3	DMA controller initialization error
	Error in initializing the RAM regeneration circuit.
1-3-3 or 1-3-4	Error initializing the first 64 KB of RAM.
	Motherboard initialization error.
	Error writing/reading to/from one of the I/O ports.
	An error was detected when reading/writing bit 0 (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 1st bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 2nd bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 3rd bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected while reading/writing the 4th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 5th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 6th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 7th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected while reading/writing the 8th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 9th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 10th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 11th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected while reading/writing the 12th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 13th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 14th bit (in hexadecimal) of the first 64 KB of RAM
	An error was detected when reading/writing the 15th bit (in hexadecimal) of the first 64 KB of RAM
	Error initializing the second DMA channel.
3-1-2 or 3-1-4	Error initializing the first DMA channel.
	Error initializing video memory.
	There were problems when trying to access the monitor.
	The video card BIOS cannot be initialized.
	Error initializing the system timer.
	Testing is complete.
	Keyboard initialization error.
	Critical error when the CPU enters protected mode.
	Error initializing RAM.
	Error initializing the first timer.
	Error initializing the second timer.
	Error initializing one of the serial ports.
	Parallel port initialization error.
	Math coprocessor error
Long, continuous beeps	The motherboard is faulty.
Siren sound from high to low frequency	Video card is faulty (damaged capacitor)
Continuous signal	The CPU cooler is not connected (faulty).

Note! If there is no signal: there is no speaker; The built-in speaker is faulty; motherboard defect; BIOS system failure (try and restart).

Instead of an afterword

If you observe one of the above malfunctions in the form of signals (except for a single short signal), seek help from specialists service center for repair and maintenance of computer equipment! Try to be careful, any attempts at self-repair or interference with faulty equipment may aggravate the problem.

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If you hear two short BIOS beeps shortly after turning on your computer, then this is an alarming symptom. Such signals are generated by the system speaker of the motherboard during the PC hardware test (POST) procedure and indicate a detected malfunction.

Since different BIOS encode error signals differently, the meaning given this message in the BIOS, depends on the specific motherboard, or more precisely, on the BIOS chip with which the board is equipped.

In the IBM BIOS, two short BIOS signals indicate a video system malfunction. Award has 2 short BIOS signal code a malfunction that is not critical, that is, a malfunction after which booting the computer can continue. Such a malfunction could be a failure of a hard drive or a BIOS checksum error. Typically, in this case, the BIOS will display a detailed error message indicating the faulty component, and the computer can usually continue to boot, but only after pressing a specific key, for example, F1. Sometimes, to correct an error, the user will need to enter BIOS Setup to make the necessary changes there.

However, it should be borne in mind that even if the computer can be successfully booted after two short beeps are displayed, you should consider eliminating the problem, since it will bother you again later.

The list of AMI BIOS sound code messages also contains two short beeps. But in in this case The error that causes this message is related to the RAM test. If such an error occurs, you should check that the RAM modules are securely installed in the slots.

AST BIOS may also produce 2 short beeps, but this is usually associated with another problem - a keyboard controller testing error. In Quadtel BIOS, two short beeps mean something else - CMOS RAM damage. Finally, the Compaq BIOS emits two short beeps when it detects common error motherboard. 2 short signals have the same meaning in the BIOS that is equipped with IBM laptops ThinkPad.

Today we will talk about the situation when the computer, when turned on, emits 1 long, possibly repeating signal after some time, and does not display anything on the screen.

In this situation, there are clearly problems with the equipment. Depending on the motherboard model and BIOS manufacturer, 1 long signal can indicate various problems.

Phoenix BIOS thus notifies the user about a fan failure in the CPU cooler. In Award BIOS, such a combination indicates problems with the power supply. And for Compaq BIOS this means a violation of the correct functioning of RAM.

The IBM BIOS notifies you of video system problems with one long beep. In some cases, the user can fix such a breakdown on his own. You just need to check how correctly the video card is positioned in the motherboard slot. Perhaps the device needs to be adjusted a little, and the annoying signal will disappear.

AST BIOS in this case indicates a breakdown of the microcontroller. More precisely, the signal indicates an error detected when checking the first DMA channel. Often, to correct this situation, the user has to change the entire motherboard.

Remedies

So, the first thing to do to solve this problem is to try to remove and install the RAM, after wiping its contacts with an eraser. Ideally, take another known working memory and insert it in place of your own.

One possible reason for this signal sequence is RAM

If after this the problem does not go away, check whether the processor fan is connected to the motherboard properly and whether it is jammed. To do this, try scrolling it with your finger. The computer must be de-energized.

Checking that the CPU cooler is connected correctly

The next step in eliminating one long BIOS signal is to install a known working power supply, which you can temporarily borrow from friends or acquaintances.

The power supply is one of the possible reasons for 1 long BIOS signal

The last step in trying to eliminate the long BIOS signal during boot is to try to remove/install the video card by wiping the contacts with an eraser.

Installing/removing a video card to solve the problem of one short and two long BIOS signals when turning on the computer

If after all the described steps you are unable to start your computer, then most likely you will have to replace the entire motherboard.