HP P.O.S.T BEEP CODES  or Keyboard LED BLINK Error messages.                            
BIOS means Basic Input Output System (a.k.a: ROM BIOS, or BOOT ROM and BIOS FIRMWARE)
Beep/Blink codes
are  super complex and tedious and for sure arcane  and
esoteric! (some  PC's beep, some blink and others do both)
The codes are S. MORSE (like "SOS") like but non standard from one PC maker to the next. (amazing as this seems , some PC have 5 codes other 25 or more!)
The most complex part is there are so  many versions of BIOS for 36 years (1981 IBM PC to now) (and endless revisions )
The sad part, is that its worse today, (wiki UEFI and cry!)
The fact is there is no UI, standards for BIOS, (user inferface or GUI standards) 
There are features, on some PC (lame), that are missing here, even show stoppers!  Like ROM-Extension Bypass turned on, and no place to remove it)
My pet peeve is the lack of  Verbose enable bit to make bios report all bios check points as it boots (call it debug mode) wow !
Back in the 1990s some did, hit the ESC key booting and it did go VERBOSE ! loved it I did.

My Chaos page:

This really IS BIOS P.O.S.T ERRORS power on self tests. , as it discovered bad things (serious too)  , mostly hardware errors discovered or missing or bad hardware (aka: chips or all RAM missing...or shorted)
These errors you see mean, "fix me first", errors.
Some PC will do POST errors for "no boot device found" and worse still (IMO) is when this happens on newer PCs it goes in to and endless boot loop, how stupid that is, no?)
POST means , power on self tests.   (BIOS also runs a preliminary PnP service (plug and play)

This page covers old beep codes and most, modern CAPS LOCK LED key BLINK CODES:   (or my very unique HP workstation ! XW4600  as will a great Z600 ! My favorite)

Flashing means, Flash programing (burning) the SPI BIOS: (So I use the workd BLINK to avoid confusions)

If a PC acts up, we do the  standard HP long  ReSet,

We also know a bad RTC CMOS coin cell will cause any BIOS made  to go dead or to got totally nuts and for sure the PC can not hold time of day or the date, consistently.)

How to use a P.O.S.T card and see all BIOS check points.( and all errors)

If the HP/COMPAQ is older than 2010.  see these caps lock blink codes.

Top hints, on old PCs , take out that Laptop huge battery first, and see if POST errors go away.
  1. The Laptop remove the main battery first to see if  this error clears, batteries main can short and overload critical, power regulators inside.
  2. Replace the dead COIN CELL now.  (below 2.9vdc it's on the death cliff) {a simple voltmeter test ends the wondering}
  3. Remove the HDD next, sure some short. (but one BIOS reports failure to boot, so doing this makes that error more true)  (run F11 restore startup files fixes then no  more boot errors  from BIOS)
  4. Remove the CD/DVD drive.
  5. Remove all up top, 4 RAM sticks (DDR) and test them 1 by 1, in bank 0 slot. (boots now? ok?)
  6. A tech real would then start removing all things on the mobo , knowing that things can short. (CPU last and with CPU out, the poor thing is now brain dead and no beeps now.CPU almost never fail but do shut off too hot.)
When doing the above  note if the beep/blink codes change.? If yes, BINGO !
My Laptop PC has like 6 modules I can pull. ( see it naked here?)

Do not forget to go to the BIOS advanced page and it set BIOS DEFAULTS (and cross fingers it's a fix)
Do not fail to remove all power, from the PC, batteries, and power line, and packs. and then discharge the PC with the power button pushed for say 15seconds or longer... Does it boot now error free? back on AC power only?
The most common code is a dead CMOS BIOS NVRAM battery called the COIN CELL.  (replace it and never flash BIOS for this error ,or you risk bricking the PC)
This is common due to its short life. 2-5 years, less if PC is on shelf for years, parked.

LIKE THE KIDS MOVIE "THE ENDLESS STORY"  Behold endless BIOS changes,  It will blow your mind, nobody standardized this, sad  to say.
This fact alone makes working blink codes a real pain in the ash can. (and archane !)

What I do first is try to learn what BIOS is there, Name and Version, and can get lucky Google searching that alone.
There are vast blink codes  possible today, due to the codes changing every few years, from 1984 to now. (at HP) longer if IBM PC.
There is great confusion on codes, for that reason and 2 more. (not so true 2010 and newer)
  1. Phoenix™ merged with Award™ and error codes get mixed  up and very complex for this fact.
  2. Most top makers of PC now order custom BIOS modified to their needs and sure error codes. (always  get codes  from you actual PC maker) HPs' new BIOS 2015 and newer is here.
AMI is the other maker of BIOS.
It would be wise for all PC owners to enter BIOS setup (power on hit ESC) and see what is there (name of maker and version #) Mine today shows.  HP BIOS, SETUP VERSION; F.06
There are beep sounds codes (Morse code like)
or CAP's Lock LED blink codes.(modern) or power lamp LED flash codes.

Or if you have a PCI POST card, we can see the binary errors too. (complex and I will not cover this)
There are many fail paths possible. In no order but Coin cell dead ,does win most bets. (it and all batteries have short lives) not one runs for 20 years.
Bad power (AC pack weak, but not dead)
Can't compute (CPU dead) vastly rare.
Bad main battery (shorted out overloading the power bus and or onboard regulators)
Bad coin cell.
Bad RAM. (or GPU chip/card bad or even missing)
Over heating.... all this  its the most common failure on any PC made (those with fans only)
Shorted modules. (we remove them 1 by 1 to find out WHO is shorted ?
Or simply , I can not find a boot device (HDD ,CD, USBstick ,etc) Can't boot the OS. This can cause boot loops, endless booting landing NOWHERE.

Compute failures:
Learn that the BIOS can lie to you, even if all BIOS software(firmware) is 100% perfect.
If the processor can not compute accurately , how can BIOS be telling the truth, answer, IT CAN NOT.  (over heated or bad power in the systems power rails. weak power, low bus voltages or regulators overloads)

This PC like all PC's have a Von Neumann Archetecture., and if any of  these 4 buses fail?, for any reason !, BIOS will LIE. (Think about that carefully)  if the poor thing can't compute error free? , why expect truth?
  • Power bus
  • Address bus
  • Data bus
  • Control bus.
One code tells you it's saying the BIOS ROM code checksum fails or BIOS  corruption errors? (bad COIN CELL) repeat that 3 times for effect !

The long story now,  tests and steps to take.
Make sure the Laptop  main battery is good before flashing it, , if not sure take it out now. (so it can not overload the system power buses)
In all cases,  it may be best to put in a new COIN CELL battery then do the long reset here , reset the system    The DT coin  battery change out looks like these ( LP coin)
Run with no LT battery main present. (even if you have to unplug it deep inside)
Make sure the fans work , all of them so it can not overheat.
Make sure the power pack puts out 19vdc, 65watts min, on  laptop.

( Read this HP page)
I strip the MOBO down: (powering off fully , each step , never hot switch parts, except USB) I use and external USB keyboard to do all tests)
The real internal KBD has  no LED's at all. I get no BLINK code for a  missing keyboard.
In most cases the CPU is OK. (not overheating  )  (no bent pins sure, or dead fan or heat sink fell off or the thermal compound there is not like dried glue and cracked)
Obviously we start from easy to harder. (case splitting last)
I will do a list, from mine, as an examples: (I have full memory loaded, huge, memory to make W10 64bit FLY, with 4 sticks of RAM) My HP 8540w is a 2010 year PC LT.

  1. Main battery pulled,  they can short and cause havoc. (LT only , LapTop )
  2. Make darn sure the power pack is the correct wattage, 65 watts min, 19vdc. (Laptop only) (RTM read the manual?) Mine is 100w due to powerful GPU upgrade and i7 upgrade.  (Put  that DELL pack away)
  3. On the desktop (DT)?, make real sure the PSU is ok. we use a volt meter here. (a whopping $20 tool)
  4. All USB devices removed from PC external ports. (then put back the keyboard or mouse if needed) On any laptop I have the onboard, keboard removed now so I can find "MODULES"
  5. Open all LT case hatches, can be 4 or more there, on the bottom. (see things that unplug there, sure !)
  6. Remove all small modules seen under hatches. (not DDR RAM YET) like WIFI and modem and others. (minor options  bluetooth, and more if seen)
  7. Remove the HDD, and DVD drive now (LT hatches)  (on DT pull its SATA  cables (DT case side off, sure) DT = desktop.
  8. If a DT, remove the PCI slot video card and see if that pesky blink code goes away.(or changes)
  9. My HP 8540w LT has video card too, I pull it too (and is very hard task heat pipe off)
  10. On my PCs I have 4 banks of memory I have them fully populated, I now remove them all and retest each in bank 00 slot. One by One. (if one is bad, you will find it now)
  11. My LT has 2 RAM under the keyboard . I pull them.
  12. My LT with no RAM the FAN IS DEAD, sure no boot, but  the top row (power on panel) of 9 LEDs turn on then off, repeats, and the 4 front LED, power hdd, etc.  they dance a funny pattern.(oddly) No actual codes.
  13. I did pull the CPU on mine and no true codes expected but  the  other Power Processor chip in my LT, blinks the top row of  LED banks, from sound , wifi, etc like this Video shows.
  14. My LT shows no blink codes for NO HDD present. (as some do !, some newer HP LT have power blink codes, others have Cap/num lock codes.)
  15. If a LT ?, I must split the cases per the HP service manual, to reach remove many (6+) modules and  the card reader , see these other modules.
The modern PC with power LED #2 from left blink codes are this
  • 5=MEMory
  • 6= GPU (video card or chip)
  • 7= MOBO main board failures.
  • 8= CMOS battery death (coin CELL)
The modern codes for (2010+) for CAP/NUM LED blinks are
  • 1=CPU
  • 2=BIOS
  • 3=MEM
  • 4=GPU
  • 5=MOBO
  • 6=BIOS AUTHENTICION (or power weak?)  I've no clue on this.  The BIOS Password scrambled or the UEFI protections are messed up?
Some PC have  Flash code called CROWBAR.
This mean the power regulator shut down, or is overloaded,  start removing modules to cure this catastrophic error on power.

If the F9 key works,  BOOT ON THE FLY CHOICES, I pack USB stick (or DVD) Knoppix and test the system and all memory now.
Run extensive RAM (DDR) tests now,  the more rigorous the better (BIOS RAM tests are toy grade)
We use Linux boot DVD to run deep memory tests, with complex patterns... (wise this) ever seen a DVD called KNOPPIX 7 +?  all you need is there, to run disk and ram tests.

Title NO RAM: (a very short movie)
Here is my HP8540W Laptop video, with many parts missing,  even with NO CPU the power control chip can still tell you (strange blinking) that it is missing. This is the final strip down, one thing at a time to see what codes I get.
This finds the cause of  blink code more easy, when the code ends at say mem stick 2 removed or ANY other module even wifi or modem card, or anything.

MP4 9-Second video demo, no CPU

OGG 9-Second demo , no CPU (Firefox likes this)

LEGACY: older than 2010: (seems nobody wants to support legacy PCs , HP calls them RETIRED)
Other PC's with older BIOS: This section is on LEGACY PC's old and retired, and poor support at HP.
HP has this page on BLINK codes et cetera , covering  newer PC's. Before and after 2010.

The old codes are the most hard to dredge up.... See old Phoenix V4 book here. page 39(pdf page)
On super old PC , BIOS V4 one beep means I'M OK. "One short beep before boot" this means booting NOW.

Even overheat codes from users not cleaning there PC's of lint , tops the all time #1 cause of  failures.  CPU overheat codes ! All PC like cars, need service, and cleaning or will fail.

The Phoenix BIOS ,seen in the above links, has the most codes of all. 50 codes or more !  SHOCKING NO? But may only beep 10 ways. 

AMI BIOS had 8 codes.
Award 6 BIOS does a long beep and then sends messages to the screen.

Most PC 10 years or newer all do BLINK codes now.
Remember to see if codes (beep/blinks) are short or long, and do know they loop,  for example 2 blinks long delay, repeat, endlessly is code 2.
Amazing, HP has a page just for this too.

The beep codes became, and moved to the NUM/CAPS lock keys LED lamps Blinking codes.  (silence is golden?)

I do not have COMPAQ blink codes or beeps, for system this old , Google is your only possible way to find facts on these very old laptops.  15 years old? (scrap it)

HP's new 2015+ blink codes here, nice that it does Desk and LAP tops in one. NEW UEFI rules.

One more from the great year 2002,  COMPAQ OLD. (but sold from HP)
(an old HP PDF, showing all those secret blink codes and beeps for D330/530 COMPAQ 2002-4)

Advanced techniques: Post codes:  This works best with a special tool and data special from the maker of you PC. (talk to them)
I have what are  called POST cards (I have many)  my favorite is my  LCD card, with cable. (1.5)inch screen added to my PC Desktop Asus m5a99x-evo, PCI slot. (and m5a78,  linux box.)
This PC is AMI  BIOS and uses these codes.          Or here.          see also, ASUS Q-codes. (if  code freezes it means that job failed, that BIOS module failed there, be it a chip bad or missing or DRAM all missing or bad)
The above document gives you a clue just how complex BIOS is, and  it runs in a serial process to start, then passes control to the BOOTED operating system last.
(last message shown on the LCD is Int19, this is boot to media interrupt bios subroutines)Just as Linux runs first.
During level 1 boot,  (BIOS runs only) then level 2 happens  the media boot of choice be that the factory installed HDD and op. sys or a usb booted memory or CD/DVD rom boot.
During level one ROM boot, errors can happen. 
Note to how the first document above tells you the higher fail codes are vendor specific,  in this case ASUS, or HP.  (code 61 to 70h and E1 to E8 and EC to EE. and up.
In all cases errors will or can be platform dependant.  (for sure at HP)
My P.O.S.T card can see BIOS progressing so called "check point",  I have  video of my M5a78  booting in to linux. (LAMP)  at the end below.
Some High end GAMING MOBO have  built in POST display, (LED bank)
Code 30/40 are waking from sleep.(newer mobo's do this) is also releated to fastsboot option too.
  • AA Q-Code: PC booted from complete shutdown with no assist, boost or cache
  • 40 Q-Code: Pc was booted / boosted via a Windows controlled method (Usually from deep sleep, restart, Hibernation etc)

If I pull my whole Memory  bank (DDR3) I get error #3F and beep code Dah,dit,dit. ( Morse code "D" for DRAM BAD?)
Keep in mind some PCs loaded BIOS to RAM first,  the executed from there first. (and some mobo use DRAM bank , and steals memory for the onboard GPU chip) so if RAM is gone, then you might get
video ram failure, or shadow ram failures. (and confuses  anyone.)  If the ram fails it can or will cause corrupted BIOS shadow RAM machine code.
Keep in mind only your mobo maker knows all codes,  so ask them if HP , them, if ASUS, them. easy no?
First pick  (click to zoom)Basic choice, (1st time words are in Chinese ! eek so pick line 1 first then pick line 3 ,2nd photo) Installed in a PCI slot, of Asus M5a99x-evo .

First pick English. 
line 3 will be new words in Chinese, for word the English, (eek 2) as seen here)(down arrow 2 times and hit enter)
See Linux boot below.  int19 , is the jump vector to the  boot drive.

See the above card rattle through all BIOS check points then boot to lamp Linux. Below.  The codes are in hexadecimal format (0 - F) So decimal 10. is Hex "A" and "F" = decimal 16.
Each maker of BIOS has  secret document (factory) for these hex codes.  (ask them directly and get it, you will..)

My live boot Video: (MP4 POST CARD device 1)   MKV    and  OGG.   and MP4 (one will work ! cross fingers.?)

Here is another POST card of  different type. (there are also USB POST cards and PORT 80 cards and others mostly useless today)  This Post card shows EE error for memory, AMI says that is OEM code for error 31,  bad memory.
Mine sows 00 for OK.  On good boot. No idea what 7F(hex) is.

What the H3LL is beeping?, this ! it is called a Piezoelectric sonic beeper,  Replacing the COIN cell is a  GOOD 1st  MOVE !  The COIN can die at 5 years. (5-7 is average) 10 is upper end of the bath tub curve.
If the coin cell goes dead, BIOS goes NUTS.( and the time clock to called RTC)

Last and not the least is to do a full reset,
Power off, unplug PSU or power packs (DT or LT)
If Laptop, the big battery main must come out or unplug it now.
Now push the power button to discharge all caps.   count to 10 seconds, then...
Wait time,  5min to  1hour your call there, try to imagine electrons, draining off capacitors large.., now, they are!
Ok go back to normal with no laptap battery (main) Always do tests on failed laptops with this removed, they love to fail, even after only 2 years. Some short and overload the POWER BUS structures.
or repeat all the above with the COIN cell PULLED  ( new coin cell is not a bad idea,  a $3 fix if over 5 years old)
That is what I call a DEEP reset.
Put all that back now.

I then go to BIOS screens, and push "reset BIOS to factory defaults" It does just what it says. (no more) "this is resetting Settings, or configurations settings into the BIOS CMOS NVRAM BANK.
The Super double dog reset, is all the above and re-Install windows, F11 way or from HP media. (and cross those fingers...)  Power on, hammer F11,  if the HDD is ok and  was not slammed F11 works.

The CMOS EEPROM floating gate, holds a charge (called data retention) for 100 year now, (and sane room temperatures, not in outer space at 100C)
The this time lag of 100 years is the super high qulity of the insulation under that gate using some kind of  pure Silicon Oxide, the makers of these chips go to great ends to control this quality factor, and do test for it and do reject whole lots of parts based even for this being wrong.  (ISO9000 stuff)
So try not to think , the chip just sits there and forgets its bits. I'm sorry It does not do that, and if it did your  mobo is now useless. 
One secret chip maker, maker has internal chip test features that allow the quality engineer to check float gate cell charges,  after  stress test as high temperature, they can do this before and after the stress test (heat) and see the drop if any.
This allows them to know just how good gate insulation really is. (hint : it must be perfect, or the product is CRAP)
How many times you can program the chip is a whole other matter, some are 100,000 times, or more. (even a million today)

CMOS NVRam works like this.
Very very old legacy BIOS. (2002 old !)
HP does have documents that are very very hard to find on older PC's I found this with a Google "Site:" search,  (an old HP PDF, showing all those secret blink codes and beeps for D330/530 COMPAQ 2002-4)

version 2.  6-4-2017