The black screen of death.                  
                   100% HP centric. (aka: DEAD VIDEO zero data on the screen EVER.)

This page covers mostly true black screens of death, not dead windows, black means no text ever shown on  the screen and means no HP /Compaq logo graphic screens shown, and means the "hit F10 to enter setup" (or ESC) text is MISSING.
The all time #1 failures, for 2010 and older PCs and monitors is, CCFL dead and the wonder of the flash light simple test.
This page is not for only windows dead, that page is here.
I will cover PC  Desktops and Laptops (notebooks/pads) in 2 chapters below.  (I will call them  "DT or LT")  
The HP page for this failure class , is covered here, (20 questions)<< I show this only to scare you !

My pre-conditions are:
The Battery horror of modern  new NOTEBOOKS are now cracker thin as is the silly battery thin, and in the service manual it shows how to remove it, do so and run on AC power only, is the PC now OK? yes, then that large thin battery is bad.)
 

PC's with LCD screens made before magic year 2010 click all screens below, and read about CCFL tube failures.
(Most if not alkll CCFL back lamps are dead, or near or dim/ yellow bulbs, blinking like mad or intermittant as H3LL)
Let me be clear, any 15 year old Laptop used every day the CCFL are now dead and useless.

Mini-Menu: "black screens"
Laptops's Only
All Screens/ Monitor problems
See the  flash light test !
BIOS dead BIOS hot keys dead?.
Desktop's Only GPU Solderballs failed?
circa 2008 !
LapTop  power causes.
Rules of the road.
Basic causes for all  PCs.
The logic list of tests. Desktop PSU fails
Fault Isolation steps.

 

IN GENERAL:
For Blue Screens Of Death? (BSOD, the same is true with windows is only dead or can not log in to Windows.  If you get text on the screen at power on, hit HOME button.
In all cases, we are trying to see if the problem is caused by 3 things, lost power, bad screen, bad MOBO (and all its subdevices including HDD, or shorts inside or dead parts inside)
This page covers only one topic and that is the screen is 100% dead, totally black, no matter what you do, and that includes, the BIOS IS dead too.  (<called "Setup"by HP but it's just good old, BIOS, (38+years old it is)  Example screens here.
Here is an example screen not dead, just to be clear.
The cause is not software, but is hardware, we know that because BIOS is FIRMWARE and always works, so black screens are a hardware failure. (only what? is the question).
BIOS means Basic Input Output System, in a FIRMWARE ROM, ROM is read old memory, that does not FORGET if power is lost (BIOS is in ROM, but it's configuration data is in CMOS NVRAM, with a coin cell at 3volts, to retain said data.)
The LT two big differences electrically, are that huge battery and the internal screen.  (I will not delve in to "All-in once desktops")  The LT also has a   battery charger located on the main motherboard, (MOBO) no, its not inside the A/C line pack at all.
In all cases, we must learn how to test, and discover , is the problem hardware or software caused.?
Try to learn the PCs are simple when they work right, but not so at all when broken,  this is covered well here. A+ Certifications,  read that and learn just how complex computers are, it's no toaster. (sorry)
Just like cars, are simple to drive but not diagnose or fix. (for the same reasons...."complexity") Know to that laptop parts can be very hard to find after 10 long years  pass.
My page below is about testing ,diagnosis , repair and cures. It is not about Guessing at all.  Sure try anothere display on your  dead desktop, but that is test., not a guess.
HOT KEYS: (at power on button and 1second later ,tap tap tap, the hot key, my hot key is "ESC" key. see next photo link)
The screen shows,    THIS !"Press the ESC key for setup !"
The BIOS (setup) is dead if it never talks to you (screen text) ,  the many years of HP progression of the main hot keys from 2002 to now is:  F1, F2, F10 and ESC.  Yes, they changed this 4 times in 15 years. (having fun yet?)
In all cases, remove all USB devices, from PC , as vast things, can short out and cause havoc or "overload". (that includes Esata port to external drives of any kind)
If the BIOS screens and text messages are dead, we listen for the fan, the fan must blow. (or you lost power! or the fan is packed in lent, all do that, packup and overheat, all do , clean it every year and avoid that?)




Desktop black screens of death: (DT only  !)                          JUMP TO LAPTOP NOW, if not a DT?:  

The minium goal here is to get the PC's BIOS to show messages as you turn on the PC.
There are only a few cases of true black screen and all are bad monitor, every one, after all it will in all cases show at least error NO SIGNAL. when it is turned on. (so turn on PC first then monitor last, see that NO  SIGNAL ERROR?) if not the monitor is dead.
The given is you tested the monitor on a known good PC and it works ok. (with the same cables).
The PC makes noises turned on, both fans spin and actually blow air.
The 2 fans all must blow air in all DT PC, and are not packed up in lint. (clean it now)
The PCs power button does not flash error codes. (sold green, not flashing green or flashing amber power button) Some PCs flash keyboard LED for errors some the power button and others set errors on the rear of the PC with 4 LED diagnosis error codes.
You could try another monitor on this PC to see if the PC is dead.
The dead monitor page is here.
The first thing I do on all PCs is carbon date it,  the users manual page 2 usually shows the date the PC was made,  if over 7 years old the RTC coin cell is bad, and on some PC this shuts down the VGA card so as not to  burn up CRT monitor screens.
This is such a simple and super common problem ths RTC coin cells are 5 to 7 year life rated (copper top spec, and pink bunny spec. tells you this fact)
The monitor will also show, text for (no signal, no sync or out of range)  if this error shows, that means the monitor can not receive VGA signals from the PC VGA JACK, but this is not the case the PC screens is all black no text ever.

See  basics tests here first.

The monitor tests good.
In all cases you see this error.
The monitor if turned on LAST shows, "NO SIGNAL or NO SYNC or OUT OFF RANGE" errors.
The below covers why you get any of those 3 error, only.
The no signal, no sync, errors come from the brain in the monitor, and means the VGA (or DVI ,etc)cables are dead from the PC.
Out of range means the PC is sending me illegal resolution signals,  (in most cases new PC , used with very old monitors that max out at 1024x768 or worse (lower)
Lets now see why the PC is dead. The PC is dead  is now the topic and only that. NO SIG.


NO SIGNAL: (or dead sync)
The Power button glows green ,and does not Flash. (if the button shows wrong this is covered only in your real matching user guide)
PCs for over 20 years made now back to year 2000, can send Blink codes in many ways.
I will bullet them. now. (RTM means read the manual, go to HP.com or Dell,com)
  1. Power lamp color not green but amber (yellow) or blinks, RTM read your PC service manual this is covered and is generationally changed.
  2. The PC can beep, some have beeper and can beep out error codes, like Sam Morse codes, but not really them. It is again unique to your generation of PC. BEEP codes
  3. The PCs has  USB keyboard, and it too can blink out codes, CAPS lock blink codes just like the above and tell you what is wrong, or at least 1 clue.
  4. Some PC have  rear quad LED error code diagnostic lamp. (RTM)

NO blink codes found:
Destops have at least 2 VGA jacks (some use DVI or HDMI and even Display Port DP now) But try them all, is my question or if you have 2 VGA jacks, one up top rear, called onboard VGA test that first.
If you have  VGA card in the top Express slot as all good fast machines do, for sure gamming rated PC, then we test only that, because the upper VGA jack is now off line with that PCI-express VGA card present.

If BIOS is dead now, the VGA jack is dead. (we already know the Monitor is good above and shows NO SIG /SYNC errors)
BIOS will be dead if power is dead or weak, in all cases. BIOS works even with the DVD drive and HDD/SSD drive cables pulled. BIOS IS always the FIRST GOAL.
BIOS can go nuts, if the coin cell died at 5-7 years old,  Some BIOS when booted check there NVRAM for CRC errors and if found wrong shut down all VGA ports, to prevent CRT (relic ) monitors from damage.
In most cases , here if not all , the screen is not ever black. Not really, if you tested the monitor correctly you'd have learned the monitor is ok and in all cases shows "NO SIGNAL or NO SYNC or OUT OFF RANGE" errors.(on this PC)
This is the nice thing about desktops the monitor has brain inside and OSD menu's and has live checks running to see of the 5 video pins are dead or running illegal signal rates.
So in almost all cases of any desktop the screen never goes dead. (unless the monitor is DEAD)
The monitor even signs on with a message or  a logo , (HP/DELL/ViewSonic or even "ENERGY STAR certified"  see it is not dead is the monitor) and then shows errors in text.  (all monitors do this, with a DEAD PC)
If the VGA jack at the PC  is dead, the monitor always texts box tells you it did in every case. see red errors above, it sure will.
The monitor goes dead too,  for out of range errors.
If you have  very new PC connected to an old monitor the OUT OF range error can happen, due to the PC running too high a resolution to the monitor.
This is best cured by setting the PC's resolution to 800x600 (yes using newer monitor) until you learn your old monitors max resolution rules.
Some old monitors pre 2010 are now dim , yellow, intermittant or dead. (CCLF LCD back lamps,(tubes) used from year 2000 to 2010 are all dead now)   So do not be fooled by Mr. Intermittent.! Okay? Buy a newer LED monitor and end this pain.
BIOS is what sends the first messages to the screen when a PC is first turned on,  like "Hit ESC to enter " setup,  if you see this the BIOS is NOT DEAD, nor is the PC truely dead. (sure Windows can be dead, as it loves to do)

BIOS dead. 

 I will try to show all possible way, for BIOS to go dead   what we tech's say  is the Van Neumann is busted.
The BIOS message that must be seen is, text, is "Push ESC key to enter SETUP"  this message must be displayed and that KEY  to work right. IF not, this is a DEAD PC, (assumes display is ok) It can be a DEAD PCI VGA card, or is overheated and packed in lint.
  1. The Power Button  pushed now the Fans must spin, and actually blow air, if not fix that first. (see my power page below link)
  2. Power lamp(if blinking green or amber , means standby mode or power failure)  The PSU can be bench tested easy. (the PSU fan dead means  a dead PSU or worse seen here)
  3. If you hear fans work and even see them , push the CD/DVD drive botton, for eject , if this works 5vdc and 12vdc are mostly ok of the 12 power rails,  but there are other voltages from the PSU that must be good too.
  4. OK test 1 and 3  are OKAY., and the VGA jack is 100% dead, that is what we test next. (but which jack, 2 VGA and DVI and HDMI and Display ports  can be seen here, mine has 1 of each)
  5. If only 1 VIDEO jack there, then that jack is dead, if you have 2 VGA jacks the lower one (PCI-e card) is dead,  when the builder put in the advanced PCI card, this shuts down the onboard VGA jack up top.
  6.  (so do not use the onboard jack in this case of 2 VGA jacks as  it will be dead)
  7. The VGA card can be bad,  so replace  ,but  if the on board VGA chip is dead , put in a newer better VGA card in the PCI-express x16 slot (upper slot) and run that. (needs new driver ) A GTX1050  is the best choice here (IMO)
  8.  Once the VGA (or what you run -DVI/HDMI/DP) is working you then need a good HDD and good OS to boot it up.  See here how to get the HDD/SSD booting up properly. The HARD drive of any kind.

Resets lets do resets now...
there are only 3 resets.  (not counting reloading windows from scratch or doing windows restore points)
 #1 is best to do after doing the new coin cell replacment.,  #2 resets sleep/hibernate mode stuck. #3 unscramables the NVRAM.
  1. Go to BIOS screens as the screen told you,(ESC key) and push the key marked, RESET to factory BIOS settings.
  2. Pull the line cord from PC to wall power AC,  Push the power button, hear fans run for 1sec and die, this  drains dead  the charges on the systems large capacitors.  Wait 5minutes and turn back on the PC to test it.
  3. Same as above ,#2 but pull the coin cell, (below 2.9vdc is a bad cell) then let the PC sit for 15min to 1hour.  This will get remaining caps discharged. , Ok put it all back now and repeat the above 2 steps.
Do not flash your BIOS, or risk Bricking it. (It is ok if you learn the ropes first, but most folks do it blind and brick it)

The Off Topic is Blue screens of death. BSOD's we say.
If the PC blue screens of death happen that is a whole other matter.
Windows 10 dead, see this page for and easy fix, (kill dead fast boots and win)
If  windows is dead, or restore points missing are no good , or no cure HP has  Hot Key called F11, (2007 and newer PCs)
Power on, and hammer the F11 key, and the OS reloads from scratch, all your data and apps gone now. (only if HDD is good still and not replaced ever before) The partition is called HP_recovery when un hidden.
Did someone SLAM your PC,  (installed an unsupported OS on it?)

SHOW AND TELL? (I have a GTX 1050 card here, super nice card, and to test it we must use GTX#1 jack, (unless using HDMI or DP)
The extreme example, below, to test the video here, you can use the bottom GTX jack DVI #2, because with this card inserted the BIOS shuts down all top jacks autmatically, (on relic PC it must be set manually in the BIOS)
Gamer PC, up to 8 video ports here. (most owners of old PC's have 1 or 2)  A best choice for a PC if ever there was is this.(future proof )

end desktops. (I do not cover ALL_IN_ONE PCs at all) 


LAPTOP black screens of death: (LT)
The laptop moves the screen inside, making it much harder to test.  (and easy to break , in mobile abuse/use)
This section below LT only  is in adjunct to , basics tests here.

The goal, just like above is getting BIOS  screens first working and alive and presenting all BIOS Screens.)  F10 key or ESC key hammered at power button turned on, quickly after.
You are here if the screen never ever shows text , nor the HP  BIOS logo or COMPAQ logo. (it BIOS works with hot keys on demand this page below  is the wrong page, hit the home icon above or your back button, and see Windows boot failures)
The HP page for the long 15second power button reset is here (no battery , no line cord, method , 5 steps)
The laptop (notebook et cetera) has different test steps to learn what is truly wrong.
The Laptop screen is not a standalone device,  so can not be tested on another PC. (sure in a matching laptop and long hours of hard work splitting 2 LT cases ,nah we won't go there...)
The Laptop also shares resources with the actual LT computer, it uses power from the laptop internals. (saves the builder money, but makes diagnosis 2 times harder)

The Laptop can have  CCFL back lamps (2000 to 2010 years) or LED later, both can fail but CCFL takes the cake there.(as does its funky Inverter supply module) Just like external monitors can fail the same way.

See Laptop  DISPLAY TESTS HERE
Here is a list of tests and failure modes.  (power failing tops my list and the 2 ways to get that and more)
  1. NO POWER , the 18.5 to 19vdc does not make it onto the LT motherboard (MOBO) or one if the regulator (still good) are overloaded by shorts anywhere inside. Bad power packs happen. (a $8 to $15 fix too)
  2. Overheated PC,  will not boot, if it overheats or does and dies soon. (some can overheat in seconds) (all vents cleaned, the fan cleaned, the fans Radiator not packed in lint !!!)
  3. The the main huge LITHIUM battery is bad, or worse shoted,  take it out until we make progress, Below.  (you can run on AC pack for ever,  no issues sitting at your home desk)
  4. BEEP CODES:"  The  LT that BEEPS or Blinks secret codes on the keyboard  LEDs on top of the laptop. Tells you what is failing, on mine it Blinks  the Caps Lock LED, keys.  Kinda like "S.O.S"  MORSE code,  but the codes are unique to specifica HP models.
  5. The RTC COIN Cell, old ,dead, or weak will cause BIOS to mad and time -dates to go crazy. (can cause many symptoms, black screens ,and can't boot or can't run BIOS screens and cant keep time of day.
  6. The next tests is the , try my external LCD monitor test,  I just turn it on easy with the VGA toggle hot key for is  here.Fn+F4  (even with the HDD removed this works in BIOS)
  7. Some newer LT only have  a HDMI jack to do tests for Display data(or needs a funny adaptor.)
  8. If the external screen  works now only, then that means the internal screen is bad., or the CCFL is dead.  (see monitor/screen tests here , Laptop)
  9. The goal is only BIOS screen working FIRST,  the OS is not the topic on this page at all.(Windows dead, BIOS ok is here)
  10. Inside the PC are many modules, that can fail, short and  overload power buses, killing power rails dead, as see here.(see tests)
  11. See progressive stripping  down any PC to find the causes of all overloads or any devices that can in fact upset the  4 buses in the PC (power,data,address &control)
Other causes for BIOS to be dead.

The AC power pack creates DC power and goes to the LT D.C power jack its 19 volts Direct current that any meter can measure if you want. Below 18vdc is  not good.
A common fault on cheaper LT is the DC power jack .
Some LT (poor grade) have the 19vdc coax jack soldered direct to the MOBO, and all fail every one does fitted out like that.. This is bad news.  (fixing it can be very hard work and  special tools)


The Below shows finding devices in a PC that overload the PC bus structures, (all 4 buses)
Simple ways of progressive stripping down any PC made, for sure to do any fault Isolation.
How to strip a Laptop to find shorted modules or bad memory sticks, etc.
In most cases we do this in order of easy to hard, sure the laptops are pain to work with, why own one  if portable is not needed?
Bad things in electronics can be:
  • Dead
  • Good
  • overheating
  • loose.
  • shorted in 4 ways (if it happens to  power then regulators shut down kill some or all things that compute, including BIOS)If it shorts the other buses, the PC can not compute at all.
  •  intermittent.
  • Soaked in coffee or Cola.  (contaminated) or worse, there is always worse (dropped in lake? or far worse the Ocean?)
  • Some can fail and make noise, electrical noise that closes other things (and it) to go nuts.
The PC is huge collection of chips, CPU/GPU/APU  or SOC or some glue logic , like the great and common ICH9 chip. (one common chip is the Intel CORE 2 chip CPU, and has even more special power needs)
Each chip has power needs,  5v, 3.3vdc and more. (the destkop has 12vdc for fans and the HDD motor , the latop HDD is 5vdc only drive or SSD.)
PC's all have power rails.(aka power buses)
These rails are powered by DC power regulator chips . (the are pretty smart , they protect your Railed chips from blowing up and it protects itself from burning up)
If any rail regulator is overloaded it shuts down or lets voltage drop and go out of spec, and vast numbers of chips start to fail or act oddly (crashing the PC)
Given this simple facts one can remove all modules on the PC 1 at a time, to see if the shorted device, cures the overload. (PC wakes up)
The PC has digital buses too, that must not be shorted, data bus and the adress bus and the control bus....  see Von Neueman magic  is still alive.

The most common trick is to pull all RAM sticks 1 by 1 and then run 1 at at time in Bank 0 slot,  the one that works is ok ,the one that overloads the PC is bad.
Remove all usb devices, and even any eSata devices from PC. Remove the DVD drive and HDD, is easy on all PC's ,but  on desktops it's just a 2 cable pull in seconds work.
I can pull all this modules seen here.(wifi  moduel, and relic modem card, express cards,  and more, all those seen there, off the main board.)

One can go to these 2 extremes , Laptop or Desktop.

The next thing is beeps and blink codes must not be ignored! (   beep codes or blink codes (from caps lock led)  covered here.) at you PC, look at it with the CASE removed,  that is Your PC,  real.
See all those parts there , bingo remove them 1 by 1. (CPU leave it alone the never fail) Never means owner did not do something dumb. (overlocking it to death is not IT'S FAULT, or playing with it and bending pins)
Learn that some LT have 2 banks of memory one bank top , one bank under the main MOBO,  the hint here is to look or RTM (read the manual) first.Mine has 4 memory slots. (for the i7 CPU)

Learn that most PC's the main board (mobo) can be stripped down  to just (power, main, CPU and 1 stick of RAM to test  just that, a minimum system)even using an external screen as my photos above show.

Now the long story.,.. examples can help...

Next are EXAMPLES , real:
The goal here is only BIOS working on this page....
So what can BIOS do.  ? (a short list)
  • It "BIOS" can show many screens. (even tab screens)
  • It can show the INFO page seen below.
  • It can allow you to set any possible Boot-able devices. (and BOOT order or enable them or disable them) It's programmable , all this is, by you the owner.
  • On my Desktop I can even see the fan speeds, (RPM) and all DC  power line voltages, 5v, 12v and more....
  • It has  RAM test and  Hard disk test, both are very rudimentary but If they fail, take that to the bank, as true.
  • The HP manuals cover all this, but our goal here is just getting the 1st BIOS screen ALIVE.
  (BIOS needs no HDD /SDD to work, ever except f11 recovery) BIOS is the minimum intelligence in the system (near); it's a ROM full of machine code, ready to run at any time you want .(eg: Power on hammer F10 or ESC as the screen tells you to do)
I push the  power button and then tap ESC on mine, (tap,tap, tap) until the screen says,  Entering SETUP. (in white text over a black screen)  this message proves its not a black screen of death PC,  see?
I then get the BIOS PAGES on SCREEN now.

When you boot the PC you see BIOS hints on the screen white words, on black, that is BIOS talking to you,  on lower left corner for 1second "Press ESC key to enter startup menu" this is BIOS. (CPU machine code ROM running, brains !)
eg: my HP8540w LT , If I press F1 my screen goes white, with BIOS INFO page, if it hit F10 at the above ESC prompted I go directly into BIOS setups screens, see your PC is NOT DEAD , is it.?
These hot keys, are different, on each makers PC, and is covered in your service manual,  so check it out. (All PCs, LT or Desktops,etc)
Beyond simple checks we can go deeper...  

Next I go to HP.com and read the BIOS page documents on my exact PC. To learn what KEYS MINE USE,  (varies by generation of PC and makers.)

See how to get to BIOS screens, using the BIOS HOT keys at   POWER  :  

ALL most all PC's made can produce,  Blink codes,  or BEEP codes, newer PCs use Blink codes and HP tops this list. ....
Nothing about any PC is so hard to learn or research than these silly but very important blink/beep codes,  for 2 reasons, HP changed it every 2 years for fun , the deleted online manuals on PC after only 10 years, DELL does better here.
Changing BIOS makers 4 times  or more...
No worse documention exists tham  BIOS, and worse now with rapid UEFI/TPM/SAFEboot changes and no document updates (text/docx/pdf)  A REAL pain this is,but I will try next.
If you have  HP workstation,{WS} (I have 2) turn off all PXE features in BIOS  or the PC will never boot up the HDD.   (WS are extreme quality PCs like my Z600)
See my Blink/ Beep page.

 

Ok,  more tests , deeper!
MORE EXAMPLES :
Laptop Case top off. " DC POWER" checks:   A LAPTOP.
I get to my power connector inside, LT and and with my magic voltmeter it's 19vdc on those 2 pins there,  turned on, telling me power is okay.    We can use a $20 DMM meter from Walmart ,to do this test.
If the 19vdc power  is low, say I measured 15vdc ,I'd try a 2nd pack if its low, then the laptop has shorts. ( I have a 4 ohm 100watt test resistor I use to test my power packs, by them selves. )
I can remove many things off that MOBO. To see if some option there is shorting out power. (video card,wifi,bluetooth card, DVD drive, RAM, card reader card, and more , keep and open mind, anything can short out)
To see if Blink codes  change or  go away as I pull or add things, do not hot switch parts, have the huge LT battery out all the time, and pull the line cord before each test. 
(I wait for 2 -5 minute pass before removing or adding parts at this deep level, letting many internal Capacitors discharge fully and  naturally)
See , me doing magic testing here?  Most folks don't know this. I can run the MOBO naked like this, NO CASE ! AT ALL.
I have almost all things pulled here, but not CPU/GPU, even the fan can be pulled for 1min test to see if BIOS wakes up, keep a wide open mind on what can short (answer is ALL THINGS CAN)
See my A.C.  power line left top? MOBO, See LCD? that just plugs in? See a DELL USB keyboard there, (original key board is not plugged in)
 See fan spin fast? at power on? it must,  See BIOS work?  I could even boot to windows if I added the HDD now.  (no loose Heat sinks allowed)
Do not forget the BIOS has a Hard disk and Memory bank test. Run that now.
I do most my tests on an anti static ground work pad, and cardboard of that. The only rule is to never run the CPU  with out a heat sink. (and a working fan)  That cooper pipe below must be fitted correctly at all time.
My video shows me running it CPU free. To prove lamps Blink even with it missing., in a very odd way !
  2011 made PC HP8540w
This is my most loved LT,   I bought 5  dead ones and rebuilt them +SSD upgrades, for about 1/10th the price of any new HP laptop (not Chrome book)
Below is my 8540,  one can see there are 5 modules you can pull to see if BIOS wakes up.
  • Try both power packs, that is correct never own just one, pack,  it is only $8 part,  so.........
  • All USB devices removed.
  • Screen pulled and VGA monitor screen used external,or run the internal screen only and pull that VGA outrigger card,  thinking it can short too.
  • Pull all RAM but 1, then  try each 1 by 1. In bank 0 slot, only.
  • Pull the  stinking  useless dial up modem and leave it out forever.
  • Express card. out.(but doing so kills dead it's status LED,  but is not problem, to get BIOS working.
  • Wifi pulled.
  • I can even pull the GPU card, to see the PC blink codes for lost GPU; report.
  • Watch out the USB3 ports are dead in BIOS.  only USB2 work at this LEVEL !
  • The CPU never fails but loves to overheat with bad fan, or it's radiator packed in lint or the TIM is bad, (thermal grease)The Intel chip here shuts down at near 90C, so learn not to  let that happen !
The CPU will wake back up when cool (let it)
You can pull any module you want to see if problem ends, and  you will get Blink codes for most pulls.
We do pulls to find shorts. (1 small example say I pull Mister WIFI  module and the GPU wakes up. that means the WIFI was shorting the power or data bus.
Learn that there are two brain chips here,  the CPU, and the main power control processor that can blink LEDs even when the CPU is removed !!!! If this test fails the MOBO IS DEAD. (a dead power control processor)


Keep in mind GOAL #1 get BIOS screens working and then GOAL 2, get something anything to boot.
On mine I can pull, modem, wifi , VGA outrigger card, the whole Express card assembly comes out. This card Express has the power status LEDs so if pulled you lose this information.
This PC loves to Blink the caps lock keys, or Numlock key LED's in fancy codes. but not if the CPU is missing.
I can even pull,  GPU video card seen here, Keeping 1 RAM stick (DMM3) and one CPU,  this mobo even has a Blink code for CPU missing, (yes)
We pull things why? Answer to find things that are bad shorting out critical power buses.  Shorts happen. we find them this way. (learn that ALL THINGS can short out)
What do shorts cause , answer, it overloads the power bus system and kills key functions in the computer.  (or worse)
See the DVD drive pulled, HDD pulled.
No two Laptops are the same, parts locations, (there is no standards here) Only you can read the HP service manual and see what is there, and not.
Taking any LT apart like this takes, skills.  It is not a casual practices like it is on any simple standard DESKTOP. Some LT are very difficult to take down and must be done in the correct order, and not breaking fragile parts.
Most Laptops, have no GPU card like above, on mine the GPU was upgraded by me.(easy) Seen above as GPU. card.  (I buy laptops that have a card here, or don't buy that model)
Keep in mind that some USB3 ports will be dead, until the correct HP drivers for it are installed. (that means use the left  USB2 ports to boot from any LIVE CD BOOT sticks (Linux or Windows PE)
That also means testing USB keyboard at boot time, use the USB2 ports ONLY,  not my 2 USB3 ports seen on the top right. My BIOS does not use them.
One can test out most of the PC with any live boot disk, even with HDD removed.  (costs you , the price of one CD or USB stick) (to burn a CD find a working PC with a CD or DVD burner and burn away)
I have 2 boot USB sticks or UDISK as HP calls them one is Live LINUX , and one is LIVE WINDOWS PE (I have w7/8/w8 at the ready) I can boot this way from STICK or CD or DVD.
The burn software is free, Imgburn, (Google it)  I avoid CD like media now, it's slow and time wasting, I only use boot able USB memory sticks, totally, today.
I use RUFUS, to program the USB sticks from and ISO file, (Linux or live windows PE) Best is always have this stick ready for testing. (in advance)

If the BIOS works now, and the HDD/SDD will not boot, and  the boot from Live Linux, and tests ok ,LIVE boot tests work,  then that  OS on you HDD is corrupted/infected ,  reload the OS, is the cure.
The HP hot key for RELOAD the OS is , F11 on mine, power on , tap, F11 (older PCs use F10) MY OS IS windows 10, what is yours, know what you have first.
Go to HP.com and get the Media kits to reload the HP software, on any HDD that was dead or replaced.  Hit the back button  (or here)  for more facts on Blue screen failures. Blue is WINDOWS failures.
 
Peeling the Onion deeper, is always possible?  if A chip  bad,  replace it, but wait, it has SMD chips , Surface Mounted Devices ,some are flea size. Lacking very expensive tools you will not make that work, and even with them fail.
No lie, all those modules seen above are sold on ebay cheap.   Do so and win.

If you see this, it's not a dead screen at all.
This is the GOAL getting here,  this is my MAIN BIOS screen on my HP 8540w .  Best unless a super geek that keeps records, stay the H3LL out of the Security page. One can even turn on BIOS finger print mode. YEAR 2010 PC.


Here is the first BIOS page, that lets you go to all BIOS pages, inside the FIRMWARE ROM.
I pressed F10 to get the above screen.

I'm not going back to 1979 here, sorry. or to HPs 1984 first laptop, ever.
On old relic PCs running old (Blast from the PAST YEAR 2000 , 17 YEARS AGO....) BIOS V4 from say , Phoenix?  
You see this,after hitting F2 like woody wood pecker.(at the instant of power on button pushing , you) I guess this is 1994 below. (or older) or new HP computers use ESC key to get to BIOS. Then  F1 to get to INFO page,  I do this first. find INFO page, as  a test.
This is out of the Phoenix book, what could be more clear, how to get here, and what is there?  See the HDD here? 6.449GB?

Here is one more relic BIOS page,  the old ones ,where like this.  Below if all HDD are missing, then the HDD is dead (or unplugged).  These are PATA drives here. Primary and Secondary.



Rules of the road, and if you want to be electronics, savvy: 
  • Is  "first do no harm", (why make it worse?) (flashing bios for fun or hot wiring parts you do not understand)
  •  Power is first , not just the power cord to the wall; is LIVE AC okay,  but all DC supplies, and regulators must be good , no power ?or  there will be no joy.
  •  If boards, cards, batteries, modules, or anything is shorted, you will not get far, until that is corrected. (unplug as many things as you can, even USB things. and if brave , things deep inside, or get a technicain to test it)
  • If the fans are dead, that is  big clue. (CD/DVD Eject button dead,  means power lost)
  • If the old HDD makes no sounds at all (it has and electrical motor inside!) then it is DEAD, or unplugged, or the PC has no power, (sure weak power, 6vdc for 12vdc the motor will be dead) If the drive clicks madly it is BAD.
  • IF  the DT monitor  is 100% dead, and never once even shows some white text,  that meand the DISPLAY is dead, turn the monitor on last,  if it shows , NO signal , NO SYNC, the PC is dead.
  • If the LT screen is 100% dead most times that is the LT power failure or the below. (bad battery , bad power pack or both) Laptops (LT) can run with no main battery endlessly on AC power pack good.
  • If BIOS works ok, or acts odd and the  time and date act odd or BIOS forgets things, the COIN CELL IS DEAD (3v Cell)
  • In most cases the PC is just collection of 5 to 10 modules. One is bad, now. (you can GUE$$ or test,  the former takes lots of time and cash, the latter takes time . Most folks have no tools or spares, and just flounder here.)
  • Do not work (dismantling) on the PC (or monitor) with it plugged in the 120VAC wall power, hot line Power, do not.
  • Do use ESD antistatic measure, (google that) a ground strap on the wrist is best , easy and cheap.
  • If you keep your hands out of the PSU guts you will not be shocked with 12vdc ever.  (burned maybe if you short say 1000w PSU 12vdc rail)
The first rule in all of  electronics WORK, is never hot switch parts, means plug or unplug THINGS,with power still turned on, and not discharged first.  (learning this the hard way will cost you big cash)
Exception 1: USB ports are fully hot switchable as is the eSATA PORT.(BY DESIGN)
Almost all electronics have huge capacitors inside, that hold a powerful damaging potential charge  and ignoring this one fact, many folks (noobs) blow up good parts in the PC.
If you like to swap PCI cards like crazy ignoring those hot power pins  you will blow up that Card ,the MOBO or both. Just unplug the PC and push POWER Button for 10 seconds or more. The play card swapper.A
The DT has but one power source (2 counting the coin cell) unplug the power cord and push power button.
LT(laptops) can have 3 or 4  power sources. (AC pack, 2 main batteries, (1 for sure 2nd is advanced options) and the coin cell again.  The coin cell in all cases is a harmless device.
Remove all laptop main batteries, then remove all power cords  then push the Power button for 10 seconds, now the PC is safe to work on. ( no need to blow up good parts now)
I have workstations with hot swap SAS drives, but I will not cover that now but did here. I am doing PCs only not work stations nor servers here.

 

  (all) A short History and lots of tests and cures.  See all monitor issues , here.

This is not a black screen of death, at all ,see the HP logo? , these words from BIOS?.
The above shows me the you have power, CPU works as does display, and memory and the BIOS is alive, and the HP logo is from the BIOS code.  I'd say if you can't get a boot from the HDD NOW, then HDD bad or the OS is corrputed,  Go in to BIOS now and click HDD tests.
If you F9 booted to say a Linux Live disk or usb memory stick boot of Linux now, you learn that the whole PC is ok, but only HDD is dead or its OS IS CORRUPTED.  My F9 key at power on allows me to boot to vast things. 
When I say HDD, I always mean both, HDD or SSD , which ever is your case.
If you can get this screen and  a boot CD works (Linux live or Windows LIVE PE works ) or same way using the USB memory stick boot, then the PC is basically ok.  (that means the real problem is, HDD failure or OS corruption)
If the HDD tests pass, (learn how to test HDD and save data) then the OS is bad. end story, hit F11 and reload OS.  (if F11 key  is dead, magic restore , then you need the HP media kit to fix that.)
On older PCs F11 is F10 restore HOT KEY(if the HDD was ever changed out F11/10 will be dead ) leaving only one solution. the media kit, from HP.
On even older PC's, there is no such restore HOT key, (some are named Compaq) and you need the media kit to recover Windows. (click kit link above)



This page covers all screen and monitor class failures and tests.  for all montor issues go here.
Logic way to diagnose black screens. (I will do jumps here to solve the problem) My attempt to make the shortest list here. (above arefull detailed checks)
(Ill assume you are not standing in the sun, or the screen is dim or the screen has words (words there means it's not black )   Dim screens are caused by ,  these things.
If the PC beeps or Blinks, Cap locks keys, stop now and learn what those mean, first. (it is telling what is wrong, and only HP books cover this....period)
  1. If a laptop , does the flashlight trick work? seen here (if this test passes the LCD black lamp is dead, the PC  is not dead)
  2. No, it is a Desktop so does the OSD screens work seen here.? if not the monitor is toasted. (end story) If a spare monitor works then the PC is  ok, and monitor is not. THE OSD must work,.
  3. If a laptop ? does taking out the main huge battery cure the black screen issue? yes, replace it, if not, continue on.
  4. Are all  BIOS screens dead, too?   No, then this is not a black screen PC is it, its a NO BOOT PC, and that is solved here.
  5. Ok BIOS is 100% dead, no HP/COMPAQ Logo or text telling you to hit ESC to enter setup (hp BIOS).  The flashlight trick also fails to show data of any kind in step 1 or step 2 fails above.
  6. All screens fail, even test screens on DT or LP rear VGA port.  Then we work a dead PC base. (desktop case or that which hides under the Laptop)
  7. The Laptop we check for 19vdc into the mobo now using any voltmeter,  the A/C POWER PACK must be good . if not?, try a new power pack now.
  8. In all PCs are the fans dead? or packed full of lint and jammed.
  9. The Destop PSU is dead if the fans are all dead,  PSU fan , CPU fan and if  fitted, GPU fan.  DEAD PSU's happen.
  10. Ok the PSU seems to work.  the DVD enject button works, the
  11. On desktops we have 2 VGA jacks (or DVI or mix) one is Mobo jack and other (optional) is the PCI Video card, are both dead, even pulling the PCI card now and testing the mobo VGA is wise , now,  or putting in a spare VGA card in the PCI slot to test this path.
  12. Windows 95 PCI card that works.(or this $5 card from years ago)
  13. Ok still dead screens.  Pull all RAM and try each stick 1 at a time.
  14. I now pull everything off the MOBO , (except CPU, 1 ram,  one VGA port  but I can pull the DVD cables and hdd cables for sure. On laptop top, pull all devices like that and more, NIC cards, etc.
The Key tests: listed again.  KEY EVIDENCE !
  • Beep or blink codes.  count the learn the code, write it down and read the HP service guide on you PC for the causes. (keep in mind weak power can make the codes lie ! or any shorted modules inside, that cause weak power)
  • The screen really is black even when BIOS hot keys are used !
  • The flashlight trick works or not, on all CCFL screens made,  2010 or older mostly.
  • Fans dead or packed in lint.  all fans, desktops have more fans all must be watched, and inspected.!
  • HDD is silient. 100% no noise from it will not cause black screens ever, but will cause DEAD OS, (dead windows for sure) (please do not try this on any SSD but Hibrids yes.
  • DVD (or CD) tray  button eject is dead.
  • On modern Desktops with high end mobo's my ASUS has a green PSU standby lamp if dead, means the PSU is dead, or line power A.C. is dead.
  • The Laptop runs with no battery. 
  • The Laptop runs with the correct 19vdc power pack. (not using power pack off other PC's)  65watts or more.
  • The PC runs (any) with module removed.  Yah ! parts can short. for sure.
  • Smoke coming out of PC, sure can happen, seen it vast times. For sure in PSU's (cheap)
  • If PC has 2 VGA jacks try both,  ? then try 1 VGA port with the PCI VGA card removed?
  • If fitted with VGA PCI card did the AUX power jacks fall off. seen here.
To test any PC and all the above fails. we strip it down to near nothing to find shorted modules of ANY KIND. Laptops.
Desktop  too, even to the point of bench testing them , called a minimum system.
Minimum system means just that,
MOBO + PSU, + power botton + CPU(with working fan)+ 1 stick of good ram (DDRn) in bank-0 !
Then 1 VGA card PCI-e  or the on board VGA /DVI , if fitted., some mobo have no on board VGA chips and must have PCI-e card added.
If you don't have a spare VGA card , PCI, buy one for like $5 used and keep it in your  spares box. (for testing)  Would you not be happy some day and the $5 saved a $300 labor bill?   yah..
Connect up  24pin power connector  and a power on botton,  until you know the pinout of the power on jack pins.  If you know that you need no power button to test this MOBO, ever as see below...
With any VGA monitor connected the Screen must show BIOS screens (on demand)
A Bad CPU are rare, pins not bent. (fan works, and heatsink compound not like hard as nail dried glue and cracked this old glue  like compounds, top grade compounds do not do that.)
See the VGA onboard here m5a78.  If VGA port is dead, add a VGA card in the PCI slot to see if you get SCREENS now.  Below right is ASUS M5a99fx that runs the 8 core, 5GHz, processor by AMD. (ASUS is a top maker and recommended by me)

There are 2 tricks to change from VGA onboard to VGA in slow, on new PC its automatic, if PCI-VGA is installed it goes there first. , on older MOBO you must change this inside BIOS. (on/off, onboard,  auto or order, (PCI first/PCI last)
MIN, System. photos next.
Found on the net this , nice photo  One stick of good RAM is necessary,  A case is optional . The VGA card is optional if you have  mobo like the above shows.
The below a TECH is testing his MOBO before the swap, (a savvy guy  he is) The PSU can be bench tested or in the case, seen here.
Do not use ESD conductive foam below the Mobo, doing live tests.  best is a dry brown cardboard box piece.Never use plastic, it is a ESD killer material. (if the GPU card has AUX power connector it must be used !)
  No mouse or keyboard needed to see BIOS Screens, "hit ESC to enter Setup" (HP BIOS) but if seen the keyboard is connected and ESC hit.
The ASUS hot key is  DEL key. btw.
This next drawing shows, (only on ASUS) the power pins to jump if you don't have  a power switch or is defective, , with a screwdriver tip jump PWR to Ground next to it, do not hit the +5vdc pin ever.
All top brand MOBO makers have this custom diagram, in the manual for this exact mobo. There are no standards here on THIS powersw JACK, maker to maker.
Try not to short the +5vdc pin.
this is how to cheat and not have power button, just jump pin PWR to Ground pins see at redline below. BAM it powers on.


Topic Black screen of death "NO VIDEO AT ALL", NO TEXT EVER ! ,basic basics. 
Hints:

  1. Do not hot  swap modules ever, pull the AC wall  power cord, (no main battery if Laptop) and then push power for about 10 seconds, to discharge all CAP.'s inside the PC.
  2. Learn that all PC's have 1 power rail, called standby power inside , even with the PC only turned off !  (pull the line cord ,kills standby power, let it site for 15 minutes, or push the power button with no AC, see the fans spin down?  Yah.)
  3. Do not pull modules in sleep mode or hibernate modes either. (USB devices are always safe to pull)
  4. By now you should have Video, if not?, then replace the bad GPU chip or get a new card or bypass it.  (desktops  are wonderful machines, all can be VIDEO BYPASSED, just pop in a new express GPU card, so easy)
  5. Even the oldest dirt cheap $5 Express video card will work as a  test card in the X16 top slot of a DT, and is best because you do not want  to violate the 75watt slot rule, on the express slot nor overload your gutless 250W. PSU with huge GTX-750 cards.
  6. The best GPU card to own 2018 is the GTX1050 that uses super low power and super fast card, an amazing device this is.
Desktops, if you turn the monitor on last after the PC turned on first , the monitor will text you in all cases with ( "NO SIGNAL or NO SYNC or OUT OFF RANGE") << these are the monitors brain generated messages not the PCs!
If the Desktop monitor never shows text ever, nor logo's HP/Dell/etc, nor energy star  compliant, zero data to the screeen that is a bad MONITOR, get a new one.
The monitors front face has a menu key this key must show the OSD or the monitor is TOAST. Years 2000 to 2010 monitors, are mostly dead now due to dead CCLF lamps inside.
If the PC is silent the PC is dead, if the fans are dead, the PC is dead and needs service, (see power here)
Any PC with a dead coin cell RTC battery , can and may  make the BIOS go nuts, and even cause no video at all at the VGA jack ( and the monitor shows, NO SYNC) The RTC clock can not keep proper time either. (as seen in BIOS)

Laptops:
The laptops screens love to go dead, dim, yellow, lines for data, blinks oddly, or is intermittant. (most made from 2000 to 2010 year are NOW DEAD,due to CCFL reasons.)
The laptops have integrated screens,  but you can plug in a desktop monitor at the VGA port, to see if the Laptop does in fact work perfectly , just not its local screen LCD)  (never buy a laptop with no VGA/DVI/HTML/DP jack on this side, at least 1)
Remove the laptops old main huge battery , they short cells inside and overload the power rails.  Does the Laptop work ok now.? bingo bad main battery, the #1 top failure of all laptops made (not dropped)
Run the LT on AC power only, see it will run now for eternity of until AC power goes dead in the home or whole neighborhood. (just like Desktops do, lacking UPS , power pack option)

All PCs can be reset (not talking OS reinstalls, F11 recovery nor , Windows Restore points) 
Reset now !(hardware)


Be happy you don't have this POS, circa 1981 IBM.A BLAST from THE PAST ! My first PC 8088 (intel, with BIOS 24pin ROMs )  Remember when the USA invented and made memory, sigh. AMD here. DRAM.   5 chips for BIOS ROM!
All TTL logic seen here was replaced with modern GLUE logic in the future "intel ICH9 /10 or the like" today.
 This PC replaced my old Digital Research, CPM on a S100 bus North Star, back in 1978, I had PC before the word was coined by IBM. (below is 1981 see the date stamps on the TTL logic?)







Version 7.  5-9-2017  ( a work in progress)  I'm retired but not dead.  By : DeadPool.  ,  the word flash is now used only for Flashing BIOS memory and BLINKS words are LED blinking....(not mixed as before)