When an IBM compatible computer is first turned on, the hardware runs a Power-On Self Test (POST). If errors are encountered during this POST test, they are usually displayed via an audio beep or in the form of a code number flashed across the screen. With this audio code in hand, you can determine what part of the system is having problems and find a solution.
The pattern of beeps whether its the number of beeps or the length of those beeps will give you an indication of the actual problem. Its a distress signal from the computer in a morse code like pattern. Unless you have a diagnostic card to tell you more about the particular problem, you will have to use the charts below to decipher the computer error and get your machine back up and running.
Standard Original IBM POST Error Codes
1 short beep = Normal POST - system is ok
2 short beeps = POST Error - error code shown on screen
No beep = Power supply or system board problem
Continuous beep = Power supply, system board, or keyboard problem
Repeating short beeps = Power supply or system board problem
1 long, 1 short beep = System board problem
1 long, 2 short beeps = Display adapter problem (MDA, CGA)
1 long, 3 short beeps = Enhanced Graphics Adapter (EGA)
3 long beeps = 3270 keyboard card
IBM POST Diagnostic Code Descriptions
100 - 199 System Board
200 - 299 Memory
300 - 399 Keyboard
400 - 499 Monochrome Display
500 - 599 Color/Graphics Display
600 - 699 Floppy-disk drive and/or Adapter
700 - 799 Math Coprocessor
900 - 999 Parallel Printer Port
1000 - 1099 Alternate Printer Adapter
1100 - 1299 Asynchronous Communication Device, Adapter, or Port
1300 - 1399 Game Port
1400 - 1499 Color/Graphics Printer
1500 - 1599 Synchronous Communication Device, Adapter, or Port
1700 - 1799 Hard Drive and/or Adapter
1800 - 1899 Expansion Unit (XT)
2000 - 2199 Bisynchronous Communication Adapter
2400 - 2599 EGA system-board Video (MCA)
3000 - 3199 LAN Adapter
4800 - 4999 Internal Modem
7000 - 7099 Phoenix BIOS Chips
7300 - 7399 3.5" Disk Drive
8900 - 8999 MIDI Adapter
11200 - 11299 SCSI Adapter
21000 - 21099 SCSI Fixed Disk and Controller
21500 - 21599 SCSI CD-ROM System
AMI BIOS Beep Codes
1 Short Beep One beep = is good! Everything is ok, that is if you see things on the screen. If you don't see anything, check your monitor and video card first. Is everything connected? If they seem fine, your motherboard has some bad chips on it. First reset the SIMM's and reboot. If it does the same thing, one of the memory chips on the motherboard are bad, and you most likely need to get another motherboard since these chips are soldered on.
2 Short Beeps = Your computer has memory problems. First check video. If video is working, you'll see an error message. If not, you have a parity error in your first 64K of memory. First check your SIMM's. Reseat them and reboot. If this doesn't do it, the memory chips may be bad. You can try switching the first and second banks memory chips. First banks are the memory banks that your CPU finds its first 64K of base memory in. You'll need to consult your manual to see which bank is first. If all your memory tests good, you probably need to buy another motherboard.
3 Short Beeps = Basically the same thing as 2 beeps. Follow that diagnosis above.
4 Short Beeps = Basically the same thing as 2 beeps. Follow that diagnosis above. It could also be a bad timer
5 Short Beeps = Your motherboard is complaining. Try reseating the memory and rebooting. If that doesn't help, you should consider another motherboard. You could probably get away with just replacing the CPU, but that's not too cost-effective. Its just time to upgrade!
6 Short Beeps = The chip on your motherboard that controls your keyboard (A20 gate) isn't working. First try another keyboard. If it doesn't help, reseat the chip that controls the keyboard, if it isn't soldered in. If it still beeps, replace the chip if possible. Replace the motherboard if it is soldered in.
7 Short Beeps = Your CPU broke overnight. Its no good. Either replace the CPU, or buy another motherboard.
8 Short Beeps = Your video card isn't working. Make sure it is seated well in the bus. If it still beeps, either the whole card is bad or the memory on it is. Best bet is to install another video card.
9 Short Beeps = Your BIOS is bad. Reseat or Replace the BIOS.
10 Short Beeps = Your problem lies deep inside the CMOS. All chips associated with the CMOS will likely have to be replaced. Your best bet is to get a new motherboard.
11 Short Beeps = Your problem is in the Cache Memory chips on the motherboard. Reseat or Replace these chips.
1 Long, 3 Short Beeps = You've probably just added memory to the motherboard since this is a conventional or extended memory failure. Generally this is caused by a memory chip that is not seated properly. Reseat the memory chips.
1 Long, 8 Short Beeps = Display / retrace test failed. Reseat the video card.