black screen of
First Desktops then Laptops or the like, (for All IN ONE PCs or Note/book/pads see Laptops.
This is not about Windows BSODs (blue screens of death ) nor about Windows DEAD, (this is hardware failure here)
Desktops only covered first : See Dead PC tests here. (basics) .
There is not just one symptom or evidence here on any true dead Desktop after all it has a BIG CASE and an External MONITOR, and either can fail. (if not one Pixel glows ever, much less text, that is a bad monitor! VGA cable loose or fell off?)
The monitor must show its logo and its menu button must work and if the PC is dead, the monitor tells you it is, (texted) "NO SIGNAL" (or by any other names, even "all input cables dead/disconnected" (many monitors have 4 inputs)
Learn this about VGA (use it first if you can) VGA has 5 key wires/pins, HORZ, VERT sync and RGB video, if SYNC pins go dead the monitor tells you it did and then the monitor shuts off/sleeps. (tells you both)
If SYNC pin signals are ok and any of the 3 RGB go dead, the COLORS go wrong. (RGB = Red Green Blue video)
If a fancy Video card discovers any pin is cut or open (even a bent pin) the VGA card shuts it self down. (The card does termination tests and shelf shuts down to black screen and monitor told you it did, with TEXTED ERRORS!)
If you are confused, turn the PC on first and wait 10seconds and turn monitor on next, second, and now the monitor will show errors if the PC is in fact dead. The monitor is NOT DUMB, it will report, most ERRORS related to PC DEAD.
The first clue is not the screen ever, on any DESKTOP but heard noise sounds, the Desktop has at least 2 large fans and some 3 , with 3rd fan on most fast gaming class GPU cards. If the PC is silent the PC has no power.
LAPTOPS ONLY: (the laptop fails very much like Desktop above list, but the laptop has batteries that love to fail no Desktop has.
But you can connect a Desktop monitor to a real Laptop to see if that works, now.
There are Laptops all have 2 or more bad batteries hidden bad batteries)
Most note pads are slow simple devices that do not have fans, and only have very hard to reach batteries, and still love to fail those batteries, (99% of the time , if not dropped/ hit or drowned the battery is bad) ok?
All portable PC love to fail the big battery, even 1 year old or abused (means almost never using the AC pack)
The Laptop dead, we first remove the huge main battery first and run on AC power pack only. (if this works bingo battery is bad or worse shorted , take it away from things that catch fire, these batteries (old generation) can catch fire.
Some PCs fail and go dead caused by electrical shorts, and we do fault isolation tests to find those bad actors.
Some folks like to FLASH their BIOS , and now the PC is bricked dead (self caused damage)
Jump to Laptops now.
The first thing to know and avoid:
These sections below, are examples of actual failures, tests and the cures.
Examples are always best and with photos and facts and evidence.
Mini-Menu: "black screens"
Desktop black screens of death: (DT only !) JUMP TO LAPTOP NOW, if not a DT?:
See basic dead PC page first.
The RTC coin cell loves to fail after 7 years,old, and will make BIOS go nuts and some even make the PC act dead.
The minimum goal here is to get the PC's BIOS to show messages as you turn on the PC.
If you just put in power hogging new GPU card this too can cause PSU overload and dead screens.
The monitor 2009 and older had crummy CCFL back lamps, test it this way.
There are only a few cases of true black screen is bad monitor, as seen and tested here.
The given is you already have tested the monitor on a known good PC and it works ok. (with the same cables) so is PC only issue, if the monitor works on other PC's.
All PCs made send out errors many ways, all from BIOS P.O.S.T error codes by Beeps / text or flashing LED codes, do not skip these big clues. (read you manual at oem?.com , hp.com dell.com are best PC on earth)
The PC makes noises turned on, both fans spin and actually blow air. (if not you have bad power lost power in the PSU or inside the PCs VRM's have shut down.
The 2 fans all must blow air in all DT PC, and are not packed up in lint. (clean it now) If the PC has GPU video card , and it too has a fan it must not be packed full of lint and jammed.
If the PC fans blow good , we next try another monitor on this PC or move the monitor to know good PC to test the monitor.
The dead monitor or any screeen dead page is here.'
In all cases , if you see this error below in RED:
The monitor if turned on LAST shows, "NO SIGNAL or NO SYNC or Video cable missing" errors. (means dead PC)
"OUT OFF RANGE" error means the PC is using way too high of resolution for me the relic monitor to use, so set it to 800x600 fixes this error.
Lets say the monitor tests prove to you that monitor is not dead, (tested on 2nd good PC is fast and effective way to learn this simple fact)
Next is PC sounds.(or blink codes)
If the PC is silent or fans dead or packed full of lint, then we clean the fans first and get them going first the CPU and PSU fan must blow air.
The PSU must turn on, this makes fans work and the CD/DVD tray will eject, and the Screen most POST . BIOS screens must all work, and is GOAL 1 now.
A PSU with a dead fan is a dead PSU (rare exceptions, some high end PSU the fan is 0 RPM below 100watts used ,surely you know when your PSU blows air?, but in all cases the manual on our PC should answer this.
Once the PSU stays on, and the power LED glows correctly (blinking can mean stuck in standby, reset it this way) the mother board on many PC have center of motherboard, STANDBy LED if out , the PSU is bad. (or mobo shorted or things to it)
At this point it is best to have a new RTC coin cell battery or measure it with any voltmeter made at 2.9v to 3.3v, lower is battery bad or REAL SOON.
Next is POST errors. The PC can show POST errors as beep codes, LED blink codes or POST text error to the sceen , some PCs do all 3 (nice PCs)
If Monitor tests good above, and BIOS is dead, and no Blink codes present , and fans run ok and the RTC battery is good , in most cases this is a bad PSU.
If the PSU is good and bench tested or new, what else can be wrong, causing black screens on a good monitor.
The answer is simple you have shorted (modules, chips , devices , cards (PCI) or HDD or DVD drive inside the PC. ( learn now that anything there can in fact short for sure ESD zapped or lightening hits)
You unplug the mouse and keyboard just in case they are bad, to see if screen wakes up. (remember BIOS screens are first not windows)
The answer for any good PSU not working or turns on for only 1 second, (ATX rules) is overload, a.k.a shorted modules inside the PC, (I use the word module to coer all parts inside, as you see them case lid off)
This was covered in my first link above but here is the direct link to Fault isolation tests, finding SHORTS.(aka, strip down testing)
If the PSU turns on and stays on , all fans glow and BIOS runs perfectly, but will not boot ,what then?
(I have a GTX 1050 card here, a super nice card, and to test it we must connect my DVI monitor to my DVI , video card jack. (if you have DP or HDMI use that)
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)
On some old PC there is no Video PCI CARD here and just the old onbaord VGA jack so use that, but if there is a card there, you must use that or remove said card.
Gamer PC, up to 8 video ports (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.
A laptop is mostly just Desktop shink.
In this order only:
Also some virues can wreck your Recovery partition on the HDD.
Most PC over 3 years old the Maker does not sell you new OS media install kits, (that you lost or forgot to buy 10 year ago?) I say 10 due to at that age most OS there are 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.(hp rules , yours are diffrent)
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)
Simple ways of progressive stripping down any PC made, for sure to do any fault Isolation.
Bad things in electronics can be: Keep an open mind , there are lots of failure modes.
Just BIOS screens dead?, The fans working.( running on AC only power pack no big battery)
The Laptop is the VGA screen port dead too? if not dead there, the LCD CCFL are dead in your Latop.
If both are LCD and VGA external screens are dead the GPU chip (2008) is bad
The RTC battery dead on some PCs can make the BIOS go dead or just show CRC errors to the screen.
The only sure way to find this is here.
MORE EXAMPLES : All the below are real life case examples of extreme diagnosis of a top grade 10 year old PC)
Laptop Case top off. " DC POWER" checks: A LAPTOP HP Elitebook. (has many parts to fail so is a super good example)
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. )
Not clearly and carefull that nasty old BIG battery is first to go (removed), and is gone below, not byaccident, but on purpose.
I checked the RTC coin cell first thing, 3v good. next.
One PC had shorted land line modem card, I pulled it and the BIOS screen POPed. what useless that card is and is shorted.
I can remove many things off that MOBO.
First tests are with 1 stick of RAM not 4 and to test all sticks 1 by 1, (I have 2 slots, top and 2 slots bottom ) the service manual covers this.
To see if some option there is shorting out power.REGS (VRM) like: (video card,wifi,bluetooth card, DVD drive, RAM, HDD, secure card reader card, SD mem. 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,
Warning never hot plug parts, ever inside any PC. The AC pack is pulled and the nasty big battery was out at all times here, and I push the Power button and this discharges all CAPS in the PC, and now is safe to work.
Wait 5 minutes now, just in case.
Now with a ESD wrist strap ground clipped to that copper heat pipe seen here I begin to work.
See , me doing magic testing here?
Note the case is missing now, this allows for the most fast testing of any dead PC for sure OVERLOAD.
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)
If the screen is dead (LED here) we then can plug in VGA DT monitor at the rear VGA jack and see if that works and gets BIOS screen seen below.
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.
The unseen heatpipe Radiator is on the left side of fan, and loves to packup in lint and make everything here overheat.
2011 made PC HP8540w
Below is my 8540, one can see there are 5 modules you can pull to see if BIOS wakes up.
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)
5 modules pulled, PLUS HDD and DVD, (a spare GPU card is a nice thing to have , spares are like $20 used and lots sold used on feabay)
5 modules to pull.
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, some skills. Lucky me , HP has screens an not those nasty, blind snap in parts. (HP and DELL RULE)
It is not a casual practices like it is on any simple standard DESKTOP.
Some LT are very difficult to take down (not this PC) and must be done in the correct order, and not breaking fragile parts.
Amazing enough the HP service manual covers all these steps.
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.
This PC can boot to like 7 things, HDD1/2 ,DVD, SD card, USB2 ports.
If the BIOS works now, and the HDD/SDD will not boot, and the boot from Live Linux,
If linux runs good then the harware is OK.
If the PC was not slammed, then F11 works (RECOVERY)
The HP hot key for RELOAD the OS is , F11 on mine, power on , tap, F11 (older HP PCs usee F10)
Go to HP.com and get the OS recovery Media kits to reload the HP software, on any HDD that was dead or replaced. ( only sold 3 year or new says HP)
Do not turn on BIOS or HDD passwords or you will real upset later, when you forget it. (unless you work at CIA/NSA/DOD avoid that)
If you see this, it's not a dead screen at all.
This is the GOAL getting to 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.
Here is the first BIOS page, that lets you go to all BIOS pages, inside the FIRMWARE EEPROM.
I pressed F10 to get the above screen. These screens all prove the PC Is not dead, nor is it black screen of death PC, But is the first goal.
I'm not going back to 1979 this old HPs 1984 first laptop, ever.
Rules of the road, BLACK SCREENS 100% and if you want to be electronics, savvy:
Do not hot swap any PSU power jacks inside PC's.
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 that is safe to leave be) 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 above, not work stations nor servers here.
(all) A short History and lots of tests and cures. See all monitor issues , here.
This screen shows the PC is not dead, nor is the screen but my not boot windows.
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)
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.
The power switch is a normally open , momentary closure switch , do not leave a jumper there shorting PWR to ground, endlessly.
The Long hard power reset step are easy... and seen here even done 2 ways to be sure.
The goal if above reset fails to allow at least BIOS screens to work is to diagnose that DEAD BIOS. (new RTC coin Cell battery can be amazing...)
Version 12 5-9-2017 , July 2019 minor changes