Laptop power  button is dead? or screen dead or No POST?        
                   See life span of parts that love to fail in Laptop's.
 

The below is not about windows dead , only a   truly dead PC (windows is a whole other kettle of fish)
#1 All time cause of  failure  is what?  BIG BATTERY IS BAD or worst SHORTED, .BIG BATTERY IS BAD or worst SHORTED, .BIG BATTERY IS BAD ! is this CLEAR? They can fail  one year old !
#1 cure replace the BIG BATTERY ,
first. (or work through the long list of tests below) If that takes 10 screws removed so be it (facts) if that scares you then take the PC to the repair shop.
#2 is Laptops dropped, hit, drowned , or drink spills inside, or to the keyboard that I do not cover ever, and is very expensive repairs and lots of labor ....  (The below is about non abused PCs)
#3 If BIOS is dead, that is  a dead PC or hard power failure in the PC., (the below shows how to test for this condition)


Symptoms:? Evidence of Power failure, making PC dead?

 

Going beyond the above simple checks and for sure VASTLY common causes of a DEAD Laptop or notebook /tablet.? is below,  and is  about 20 tests on full featured, laptops.

Dead PCs or ones that turn on and then self turn off fast are caused by 2 major things,  power overload, and/ or  overheating. ( this is fact of science for sure Physics and Electronics.)
PC's never cleaned wind up like this.
All PCs make heat, and if not expelled from inside any PC, then the PC overheats and shuts down, in about 1 minute flat worst case, (from dead cold) The fan in most laptops love to pack in lint and fail. clean it you must.
A gaming laptop uses huge power , yes gaming, and if it air paths blocked in lint can in fact overheat in short seconds and self turn off.
Power is King, if power inside any PC is dead or weak or bad or noisy or flaky the PC has no HOPE over running. 
All Laptops (and most portable PCs) have 2 power sources and we remove the BIG battery first and run on AC pack only, and if successful runs now, proving the battery was bad, with one simple act by you, in fact run on AC forever, no guilt.
All PCs use power to run,  (there is no hand crank here  like a wind up toy) " no Hydrogen powered PCs yet"

WHAT TO DO NEXT?:

  1. Test #1 (after power reset above done!)
  2. The big batteries love to short,  That is what they  LOVE TO DO. (go bad, or worse short out  inside) so is remove now, and keep it out until the PC runs perfectly again.
  3. Step 2: if the PC fails to run now with the BIG battery out and AC pack connected on both ends, then try a new power pack as low as $15 on EBAY. (matched voltages and watts , and watts can be equal yours or more)
  4. Got a bad JACK here? (PC runs if hand pressure is held on the DC small plug?)
  5. If the PC does not run now the PC has serious problems that can only be discovered with  full  ISOLATION TESTS. (on AC power ONLY )  These tests can be one per module present.
  6. If you get this far, the PC motherboard is probably bad,  and the last thing to BLAME ! (due to extreme cost for a new one){" my question is why replace the most expensive parts first?"}< no law against guessing but...gee...wizz...
The worst PC is this DELL XPS PC, with only 1 card,  and nothing much can be removed much 9Q23 ( as see on Dells or vast cheap new PCs) It is the polar extreme to my PC below, that is very modular and east to fix. (or the Adamo?)
Ever seem $50 RCA Tablet sold at walmart. "throw way PC"

A PC is a cluster of modules, some can have  up 13 modules that can go dead or worst (my page is all about that) SHORTED MODULES. (shorted can very easily overload  power buses or any buses in the PC easy)
A seasoned tech, knows may PC's have at least 3 power VRM rails in the PC, 1.8v , 2.3v and 5vdc. (and raw 19vdc many have) He or she then uses voltmeter (DMM) and learn the skill of finding those test points and checking them.
Most just  jerk models and trash can the ones that cause DEAD PC.

I will cover theory of operation and cover  all ways a Laptop can fail.   13 modules
The buses are in 4 types (at the least) and any that are shorted will fail. (we call power bus also the  power rails)
If something shorts out , be it power rails , address , control or data buses , the PC fails hard. (most  Computers use Neumann and Harvard architectures and are subject to those conditions!) One can say a short is any overload condition.
Also know many PCs made from 1999 to 2007 loved to have shorted capacitors ,well, everywhere. ( makers bottom fishing cheap cap's (crap caps) caused that !)

Learn first that any electronic part inside any PC can in fact short out and for sure if hit by lightening or ESD events, or bad luck or Fate. (or overheating damaged parts, shorted out)



THEORY AND TESTS: (below)  (Skip boring theory and go to strip down testing now)
The first photo below is nice block diagram that I modified greatly, from year 2005 I think.
The power pack runs the main power regulators (VRM) and  charger chip too, as seen below with MAXIM stamped chip.
If the Battery is shorted ( we always remove the big battery first) and run on AC pack now or even forever is allowed.
The RTC COIN cells can fail at 5 to 7 year life spans,  (makers spec that) and we just test them with a voltmeter. (Below 2.9vdc is bad)
 
We connect the power pack and make sure the power to say an HP  MOBO jack is 19vdc (again that meter tool) or as your PC service manual spec. states (all tech;'s know DC power is first, power must be at spec)
Some owners of PCs  like this have the wrong pack used, bought the wrong one or mixed them up with 3 other PCs in your home, do not fail to make sure the packs voltage is correct and minimum wattage is at spec,  65watt to 130watts is common.
Spec, means factor OEM specifications. My laptop has fast CPU and GPU and will only work with 100watt pack.  (with a tiny pack the PC is dead)
(Pure theory of operation) {booting up a PC is serial process up to the windows actual launch}
Next the owner of said Laptop pushes the power switch on and the power controller chip (eNe) below wakes up,  and enables all VRM and boots the PC using the attached, BIOS firmware chips machine code set.
This chip eNe   (an 8051 based 8bit CPU) checks if you are resuming from sleep or doing a cold boot. (and can be overridden with 4+ second long power button pushing)

If cold booting that chip turns on the fan first, and  makes sure the PC is not overheated (over 80C is overheated 40-60C is normal running) and then if fan is dead or weak, or too hot it shuts the PC off, very fast or delays startup . (If it has fans at all)

Learn now that the BIOS can shut off a PC if overheated or the actual CPU can too, over 80c and the CPU even slows down near or about 80c , and slowing down lowers heat. (Intel Inside magic does that)
Each maker of PC has their own rules on heat, and fan speed, most smarter PCs run the fan real fast to start, then slows down if heat is under control. (some folks cry about the noise) so some PC, risk starting fan slow. (you asked for it !)
Heat is the biggest life reducing parameter, on electronics. So running  too hot a PC is not good.
If  a PC will stay running for 30+minutes and not self shut of yet, try this application free(run HWinfo32.exe portable to see if heat is too high) The top causes are here.
In the same vein some BIOS have a power page (hot key) that lets you see FAN RPM and CPU temperatures, directly.
Next the BIOS then runs full diagnostics (P.O.S.T  for power on self tests) looking for things dead, and if dead devices found , beeps or sends  blink codes to the Caps lock key is popular. (or sends text POST errors to the screen)
The BIOS runs a localized PnP plug and play scans of all chips  (remember some device inside are optional or some are upgrades) and the  results are stored in shared RAM location for the  older OS to use.
The PC now has at least 3 BIOS HOT keys, on Dell it's F2/F12 on HP its ESC and the BIOS now (just after power on happens) responds to those keys you pressed and put you into BIOS screens (or UEFI screens)
My Dell has F12 key and in that is the great ePSA fully embedded Diagnostic, that even runs with NO HDD present !!! You do know HDD can short, or be dead or weak and useless if SMART tests fail.  < but F12 is dead on DEAD PC... so....
If the screen or BIOS screens are 100% dead, we diagnose that first, doing a full strip down of all modules possible. Up to 10 modules can be removed to make BIOS wake up. (big battery is already out)
Screen dead above also means the External monitor at VGA jack onside of most Laptops is also dead (first enabled)
The below does not happen on truly dead PC:
If no errors happened the PC BIOS  then lastly attempts to boot up, all things in order in the BOOT ORDER PAGE,  ( Make HDD0 first or if SSD make SSD0 first not the CD drive or any optical drive.)
If the PC can not find the OS startup files  it may do odd things, those things are,  shows errors (no boot found) or other odd or unfriendly things (black screens, beep codes, or boot loops , and last just shows the BIOS page and freezes.
Some PCs the BIOS if no boot devices is found of up 6 or more things possible , goes to BIOS PAGE #1 automatically, this is your  clue that "NO BOOT DEVICE FOUND" other PCs just text that same set of words.
The PC can be booted to any media, and most other OS media be it CD/DVD or USB, I only use USB now (CD;s are going legacy fast and gone) So I boot to my best Linux USB demo stick. as seen here and run full S.M.A.R.T test on the HDD.
The final tests and solutions:
The truly dead PC is next stripped down tested, we gradually remove all things in the PC to see of power can be held up and not be a DEAD PC..


The chip above looks like this below. This is a base power controller processor.
VRM = voltage regulator modules and also act as electronic fuses, (they detect load shorts and simply shut off)
If  VRM shuts down pull all modules not needed off the MOBO,  leave the CPU alone, most never fail do to self shut down at 90C.  ( HDD pulled, DVD drive pulled, all RAM pulled and tests 1 by 1.)
SDmedia card pulled, modem pulled, wifi card pulled, for sure all USB devices pulled first, to see if the PC can POST clean.
The boot brain chip is below from year 2006. This chip does all booting of any kind, and resume or hibernate modes and controls power an fans.
The Chip below is not pure logic, really it is a processor and runs 8051 instructions from the maker of your PC,(OEM) and varies by every maker, every model of PC and sub models, and BIOS version. (yes complex)



This is just one example of a chip for power control , there are many more, but one example is nice to have. The 8051 is the heart of a  very old Intel Micro-controllers 8bit from year 1980.





One way to think about any Laptop in the context of any PSU powered Desktop is to know that they moved the PSU regulators inside the Laptop on the motherboard.
Because that is what they did and added 1 or 2 battery packs and a battery charger chip to the same mobo seen above.
 (to test any laptop, first take out the huge batteries ,  usually just 1,  and see if the LT runs now.? Batteries can short, and overload regulators.
Step 2 if PC is over 7 years old is a brand new fresh RTC coin cell battery now. ( spec life span is 5 to 7 years ,stated by the 2 top coin cell makers in the USA)
The first test is always the AC power pack and my PC is 19vdc 100watts.  Only your PCs full spec tells you what packs work. (volts/amps/watts) never use smaller voltage or less watts pack stated by your OEM PC makers spec.
This Pack is just  raw DC pack. (it has no VRMs inside) (AC to DC back,  120vac to 19vdc) It is not a charger pack the charger is inside the PC not in the pack the pack is just RAW DC power.
We use A DMM meter to test voltages and for sure turning it on, or actual on now.
If the measured voltage is too low , say 19vdc measured 17v or less then  the PACK is overloaded, and that means you have shorts in the PC inside, so we do the strip down tests.

The Laptop has a large number of power regulators.   5 or 6.?
To isolate shorts in any Laptop (LT)
We remove all modules on any LT to find modules of any kind  that are shorted, and overloading any of the many regulators. (large battery out first , as they just love to short and overload power regulators)
Normally and best , power comes from the 19vdc power pack (aka: the AC pack) best is to test with only this supplying power , main huge battery out.  Keeping AC line hot, also makes the batteries last longer (LIFE SPAN)
That 19vdc must make it onto the mobo actual pins and not have broken power jack at the DC plug at the MOBO raw edge (PCB).

More Examples, I like lots of examples.
Drawing LT#1:
Here is my Laptop power state drawing,  2009 made PC.  These power states are complex and are the work of the power controller seen above. Count them 6 power states not just on and off
See to that the laptops never really turns off ever (unless all batteries {2to3} and power pack are pulled)
There are 6 states, of power operation, for sure normal, sleep and hibernate.
If all batteries are dead or removed the RTC coin cell must be good or the PC will never turn on.  (there are up to 4 power sources here, COIN, Main1, MAIN2 battery and AC power pack 19v) 1 of the 4 must be good.
If the coin cell is dead, all bets off.  BIOS goes NUTS, all batteries main are pulled and AC line pack is removed., (the coin cell  keeps NVRAM alive , with zero power from all 4 sources the PC is now dead.)
The 7th state is all things removed power wise and the coin cell, this is done  in some case to clear up chips stuck in latch up mode say after and ESD or lightening event, I call it the DEAD COLD RESET. state 7
S0 is full on power state (  S3 is sleep and S4-S4/AC is hibernate?)
If you have a schematic like me below, matching your PC not mine, we can test each regulated supply seen here.
If one supply rail reads wrong (10% out of spec or more), we remove modules to find out if one is shorted.
Never condemn any MOBO until you prove all modules connected. are not shorted by removing to clear that short (short means gross power overload)
The regulators on all MOBO all shut down overloaded, in all cases.  (that is why there are NO FUSES or only 1)
Lacking a real schematic means all you can do is measure voltages the hard way, (DC line voltages) and pull modules. Click the photo below to ZOOM to full size,.

My HP drawing #2 , logic only, not power. (the word Clarkesfield is the intel project name)  Ibex Peak is the Intel project name for 1 South bridge. HP 8540w.


One
top failure of all Laptops made is this, the LT with no pig tail seen below in red below, are the worst of all,  the jack fails. on both but the below is easy to fix, not the direct soldered Jack.
If the power cables are frayed replace the AC pack  (duh factor 1) or if you lean on the plug inserted here and the PC then turns on, gee, the JACK IS BAD.
This is the 19vdc power jack . (from AC /DC pack to here) If the below jack end face, looks bad, it is !
This nice grade,  2 pin jack the 2nd wires there is to handle more current . This is off  top quality PC not the toy grade seen in photo #1 PIG TAIL POWER , left end goes to MOBO power input jack. Power pack to the right end.

Good quality & rare to fail.
Toy grade PCs look like this and are super easy to wreck in daily use and super hard to repair !,  do not buy PCs using this  type of connector below. AVOID this. (this is cheap technology here avoid this junk)
the old jack was a total wreck, so we unsoldered it and reSoldered on a new one.

Toy grade Jack bad, hopeful this is obvious what is wrong, and the cure. (a new one)

Why assumed the motherboard is BAD, but  you can be wrong 12 out of 13 times, why assume that , why not do the tests?
THE STRIP DOWN TESTING starts NOW. (fault isolation testing this is) but if you have this  cheap PC MOBO, you may be doomed!

My example shows just one PC that is very easy to diagnose , unlike the doomed one above (linked)


Power (DC power) is king here, if power is weak or noisy or gone no PC can run. (or crashes) 

This is a running list of tests to do and actions,  in the correct order too.
Keep an open mind , as any of the 13 or more modules inside the PC can in fact FAIL.
What a tech does is strip down any PC that fails to POST at all or screens are black and no error codes of any kind, happens.
  1. First make sure the big battery is out now and leave it the heck out until the PC runs perfectly on AC power for say 1 full day. (even try a new AC pack for $15 can save the day)
  2. Make sure the PC is not overheating (if possible run   HWinfo32.exe .) over 80c is shut down   . Some PCs can overheat in 1 minute flat and turn off. (some BIOS pages do show temperatures) (in this case the PC is 100% dead)
  3. If the PC is over 5 years old we test the RTC coin cell battery  if below 2.9vdc it is  NO GOOD replace it for $1  cost.  (if this happens the BIOS can go NUTS or go dead screened,  or spew out CRC errors or beeps.)
  4. If the screen is 100% dead, see this.( we use the external VGA jack on laptops to be sure the internal screen is not dead and VGA works great externally.)
  5. Ok the screens (both internal and external VGA) are not dead,  but has errors on the screen or caps lock blink codes or beep codes.(PCs can even beep like mad the self shut off)
  6. At this point, we then suspect there are at least one shorted module in the PC and start doing the strip down testing (full)
  7. Caused by the VRM are voltage regulator modules that shut off power if anything shorts out.  (step 1 above done first; ok?)
  8. We next remove all bottom hatches on the PC,  and even the top keyboard, if it comes out easy, as mine does.
  9. Remember all USB devices unplugged and CD/DVD tray empty.... we next pull out all the easy things first, to clear any shorts, this depends on what PC you own, model # and how many modules it actually has inside.
  10. I pull the HDD first. (just 1 screw (hatches are already open) so out comes HDD and mine has 2, so I pull both, now, 5minutes work max,  if power now resumes and BIOS keys work, then you have your culprit (bad HDD shorted)
  11. Next remove any DVD drives (called optical drives now ) next.  (did this find the culprit?)
  12. My PC has a relic modem card. (like in DIAL UP Modem era, even seen on 2011 made PCs why I don't know,  but remove this thing and trash it. NOW.
  13. Remove the WIFI card   does the PC power on now and BIOS starts working, bingo culprit)
  14. Remove all RAM sticks (DDR) and test them 1by1, my Laptop has 4 DDR RAMs in it so I test each stick 1 by 1 in bank  in bank 0, as   PC's can  run in memory single channel mode covered in your manual (RTM?)
  15. Ok RAM IS NOT BAD , but PC still dead using any RAM single stick in bank 0. (all PCs have 2 sticks at least, if there are slots for them) {some lame economy PCs have only 1  stick sure but gees, why own this PC?} or this horror.
  16. If the PC has Smart card or WLAN module  (3/4/5G or LTE long range wireless module as seen and bought from the likes of  Verizon , T-Mobile etc, then remove that too.
  17. My great PC has 4 optional  GPU  modules , this too can short, so if you remove it and power stay up , this card is bad. (rare)
  18. I removed all things here but the CPU, and the PC  then powers up , just with the upper main mobo card above, you have found the short, The Express card is optional for the test but the 4 LEDS on it will be dead, but that is ok.
  19. The PC even blinks codes for all RAM missing. So mostly proves Power is not dead, with all RAM pulled.
  20. I can remove even the VGA external card to test for shorts but that makes external VGA testing impossible. (btw, the VGA port works under all BIOS screens, nice to know with LCD main screen unplugged)

 ( never seen  CPU fail ,but on old laptops they are cheap spares $10 used?)

HP 8540 ,  below has 10 or more modules  I can pull to gain power good. 


The below screens are my top goal, BIOS working. (do not run any CPU nor GPU with no fan connected  and working.)
As you can clearly see I have my BIOS screen working and the MOBO stripped naked. 4 major modules removed, and DVD and HDD, and  all but 1 of 4 ram sticks .
I can also remove the LCD (10 modules missing now) and run my external VGA monitor for as long as I want.
 This screen here is HP  main BIOS page MAIN. (HP ESC + F1 page) or Dell F2 pages.
 If this page can not be reached that is a DEAD PC, and means most times a POWER LOSS PROBLEM to solve.
If I wanted I could even boot Linux demo live from my USB memory stick and run Linux NOW. (if Linux is happy then we know the PC hardware is good, maybe not your old HDD , I never skip HDD full testing not me ever.)
The Heat sink and heat pipes are intact and the fan clean and the fan radiator (left side hidden well, is cleaned first , using CAN-O-AIR)
The below photo, I can even boot a USB stick to Linux  or Windows 7 or 10 Live PC  boot stick... in USB2 port only.
This is what I call a minimum system but the LCD can be removed too and use external Monitor VGA. The External keyboard (USB ) also works under BIOS. no need for Laptop keyboard at all) 

Watch out this  PC all USB3 ports will not boot ever, due to BIOS limits, and you must use USB2 ports on the left. (Window 10 supports both, but NOT my  BIOS even with newest version of BIOS)
The left port seen here will in fact boot Linux or FREEDOS, easy. (both are great tests of any funny acting laptop of any kind)

Laptops can last for 20+ years,  it is a fact. (but my joke is , Laptops are rated in DOG years,  7:1)
Here is list of things that never last a long time here (in ORDER of first to fail) ( A dropped PC can kill the HDD dead easy if running it is) A 3 to 6 foot drop is very very bad.(worse is to concrete)
  1. The huge battery in the LT (snaps off bottom if you are lucky like me) will in fact fail in 1 years time if abused (means not using the AC pack most the time!) {worse yet, old batteries can catch fire !}
  2. Next is at 5 years the HDD dies, LT HDD are really junk (toy) class rated,  you can upgrade it but if smart get a SSD now.
  3. Next is the5-7 year life span on the RTC coin cell, (Deity help you if you own those pesky old legacy Toshiba's with rechargeable  Coin cells. and maker does not sell them, so this is a PAIN) only them .
  4. The above power jack is bad or its end or cable end can fail at anytime, even in the first 5 years, if you stress it , it WILL FAIL.
  5. The kids played with the laptop and is now dead or is sick or someone (kids)  tried to upgrade windows, or the silly kids scrambled the BIOS or worse turn on BIOS Password and bricked your PC. (ouch)
  6. Advice, never buy a PC made in 2008 or get BGA GPU solder ball failures. (and the horrid, Capacitor plague (wiki that 1999 to 2007)
  7. Always buy a 2010 or newer PC or monitor  and get  a  real LED LCD screen, never buy CCFL back lamped PCs.
  8. The BIOS memory (EEPROM) does not forget, it lasts for 100 years, so leave BIOS alone do not flash your BIOS for kicks. ( do not flash your BIOS until you ask your PC maker how to do this correctly and matched to the your PCs serial number !!!
  9. Yes, NVRAM does forget if #3 battery above is dead. (or below 2.9vdc, 3.3vdc is new and par)
  10. Or any of the other modules in the PC bad.
Variances.: (and pains) (the worst is this)
  1. Most NOTEBOOKS for sure small, have just 1 board, inside, a motherboard and just that, and a SSD drive or just m.2 PCI mini card. (limiting tests possible to like 2 things? and main battery pull tests)
  2. Some laptops  there are no bottom hatches, nor even a removable keyboard so the whole PC must be CASE SPLIT to do ANYTHING. (read the manual RTM the service guide first)
  3. Most new Laptops are now super THIN and the price of thin is 4 fold (battery does not come out unless CASE SPLIT, and no way to fit DVD here, and  thin makes PCs frail, and easy to damage (and last very difficult service)
  4. Some Notebooks have no fans at all, so read your service manual first, see what you have first. A no fan PC uses the main CASING as the Heat sink device. (most PCs like this are slow and useless for gaming)
  5. Cheap Laptops have no upgrade paths at all or only larger SSD or  m.2 drive. 
  6. Quality PC are just the opposite of above, and have endless upgrade paths (near) and are Called GAMING PCs,  (I build these, never buy them ever)


The canard of "NO POST". (Power on Self test)  If they mean no errors at all that really is a dead PC or no power PC, as power is first , always. If power  was good BIOS usually works but not always)
Can mean 2 things or more,  (do not confuse an external monitor sign on logo with the PCs main logo, ok?)
1: Screen is dead, fully ? even the OEM logo is dead/missing. (not one pixel ever glows turned on even after the hard reset is done. (even using also the external VGA/HDMI/DP monitor dead too?)
2: or means no POST error codes/messages (full English helps no?) No beep codes, no LED blink codes at all, but screen logo is good.?and BIOS screens all work, details matter not just NO POST.
3: NO POST is really just a DEAD PC. (zero errors of any kind indicated or beeps heard)

On most Laptops I can have 2 screens working even at the same time (BIOS, settings, 1:auto, 2:LCD_local, 3:VGA , and Both)   NO 2 PCs use the same BIOS nor HOT KEYS.
Some PC have only DP or HDMI port there. (my HP has F4 hot key that lets me switch screens at any time or run BOTH !)
So if all screens fail to show error codes that is hard dead PC and  can be a  power problem  (any bus in the PC dead , makes a PC dead even power rails dead or overloaded)

version 4  11-9-2018 (HP 8540w Elitebook example is  easy to diagnose PC due to its modularity, ) (the worst is this and mostly a throw away PC if battery is good and power pack good)< Toy grade PCs I call them.