Tutorial: Audible Error Code - Power On Self Test

[s0nIc]

When a computer is powered up (turned on) a diagnostic routine is completed befire the computer gives way to software control. The hardware diagnostic routine is called Power On Self Test (POST). Errors or faults with hardware may be found during POST and these are reported to the user.

Non Fatal errors are those that, in most cases, allow the system to continue the boot up process. Non fatal error messages normally appear on the screen.

Fatal Errors are those will not allow the system to continue the buut up procedure. Fatal Errors are usually communicated to the user through a series of audible beeps. The are may long beep followed by a number of short beep and the sequence is repeated. Some BIOS routines will vary from thise shown below and some do not use the initial long beep.

Those listed below are usually fatal errors:

Note: these beeps follow the LONG initial Beep..


One Beep --- Refresh Failure --- The memory refresh circuitry of the motherboard is faulty.

Two Beeps --- Parity Error --- A parity error was detected in the base memory.

Three Beeps --- Base 64 Kb memory failure --- Memory failure within the first 64Kb of memory.

Four Beeps --- Timer not operational --- The main timer on the mother board has failed to function.

Five Beeps --- Processor error --- The CPU has generated an error.

Six Beeps --- Gate A20 failure --- This error message means that the ROM BIOS is not able to switch the CPU into Protect Mode. This is not always a fatal error.

Seven Beeps --- CPU exception interrupt error --- This is caused by a hardware conflict when two items of hardware are trying to use thesame IRQ.
(go to this thread for more info on Hardware conflict: http://www.antionline.com/showthread...hreadid=155337 )

Eight Beeps --- Screen Controller --- Display error. The screen controller is missing, not plugged in the mother board correctly or its memory is faulty.

Nine Beeps --- ROM checksum --- The ROM checksum value does not match the value encoded in the ROM BIOS.

Ten Beeps --- CMOS shutdown register --- The shutdown register for CMOS memory read/write has failed.


I hope this tutorial is useful for you...

[THEJRC]

quick addition here....

Compaq deskpro (and presario) boards can easily be troubleshot with the following method:
if you get power but no video or post, remove the cmos battery, and the memory and power up. If you still get no beeps you've got a bad mainboard. As far as I know this works for most boards, but I've seen a few differences so rather than state something that could be wrong... we'll just say compaq!!

Memory errors on deskpro's are usually 1 long beep and two short, with 1 short beep and 2 long being video (bad slot or bad card) or was it the other way around... uh oh....

On the Proliant server market, a bad processor in a server can easily be considered when the unit powers up, but gives no video and the cd rom light is solid. you will not be able to eject the cd.

if anyone has seen the new Ipaq desktop systems (designed for low cost network workstations) they will agree on the annoyance of no floppy or cd, simply a multibay in which a laptop style device is installed. The multibay will match everything from an M700 series or similar (even the older armada 7800's used the same multibay with a nifty plastic adapter) if you want to force the Ipaq to boot from this multibay (LS120 or CDROM only, wont boot to floppy) power on and hold the esc key, the unit will reboot and hit the desired medium.

hope that helps... oh and S0nic----mad props for posting this to begin with!!

~THEJRC~

[s0nIc]

HAHAHA i know.. Compaq computers are quite wierd really.. especially when i opened up one.. it was sooo different to the computers i normally open up..

hehe thanks for reading the tutorial anyway.. hehe..

[Conf1rm3d_K1ll]

I'm currently on a Compaq Deskpro now, RJC, and I gotta say....No sir, I don't like it! Although, it could be the software. It's still running Win 95, 32Mb RAM and a losy 56k modem! I like to boot it up occasionaly to remind myself how good I've got it when I boot one of my other box's.....


Anyway, as far as the beeps go you got it right.....



Sonic, where are you getting all these tutorials? That's way to much info to keep in one human head. You wouldn't be one half of a Simease Twin would you?

[Conf1rm3d_K1ll]

Originally posted by s0nIc
HAHAHA i know.. Compaq computers are quite wierd really.. especially when i opened up one.. it was sooo different to the computers i normally open up..

You've hit the nail on the head, Sonic! That's what I was trying to say....WIERD.

[THEJRC]

wipe the windoze off that deskpro.....

he he (okay so I'm a big compaq advocate... leave me alone!)
anything by compaq is usually good. as long as it's business end (deskpro, proliant)

NEVER buy a presario... man those things are just... ich....

~THEJRC~

[s0nIc]

hmm i want that IBM Netvista!!! lol damn i wish techforless was here in australia.. lolz

[MrLinus]

If I may add a few things, beep codes are dependent on BIOS manufacturer and/or computer manufacturer (in the case of the "Big" ones like IBM, Dell, Compaq, etc.). Also, hearing no beeps can tell lots. But be aware that sometimes a combination of items can result in different beep codes. A trick I used to do with students is to "break" usually RAM and Video cards. The result? no beeps. Most students "assumed" it meant a dead board. You should always keep in mind the following things:

1) Never assume
2) Make notes of everything you do. It helps to eliminate what you've already tried so you aren't repeating things
3) Don't be afraid to replace bad with good or to try bad in a working machine.

Excellent posts, s0nic! =)

[THEJRC]

take that u....

dude I'll just flake out the rate quote or something on the sales order he he international is no big dealsie
IBM's okay.... just not as good as compaq!! so there


~THEJRC~

[angelic_ky]

Nine Beeps --- ROM checksum --- The ROM checksum value does not match the value encoded in the ROM BIOS.

What does that mean?! coz I have a computer and its making that same number of beeps and i cant figure out whats wrong with it and how i can fix it.. can someone please explain this?

Nice tutorial by the way!!!