How to Check if your Laptop Power Supply is Faulty or Failing

Sometimes it may be obvious that your laptop power supply has failed but this is often not the case. This article will help you decide if it is faulty or is failing.

You may notice any of the following symptoms that may be caused by a faulty or failing laptop power supply:-

1. If the power supply has an indicator light that does not illuminate when connected to the mains then the power supply (or the mains fuse) must be faulty. The power supply in this instance should not be connected to the laptop as some motherboard faults cause the power supply light to flash or extinguish.

2. If the power supply becomes very hot when in use then it may be faulty or be of the wrong rating for the laptop. It is easy to mix up similar units between laptops. Check that the rating on the laptop ie Volts and Amps match the charger rating. The charger should show the same voltage as the laptop, however, the current should be the same or higher from the charger. Sometimes when the charger becomes very hot then it may turn off and come back on again when it has cooled down. However, this is not a safe option and it should be replaced immediately.

3. Sometimes laptop chargers produce the wrong voltage either too high or too low. Generally this can be tested by a cheap multimeter, however, a true reading can only be made under full load when connected to the laptop. But as a guide, if the voltage is more than half a volt too high or too low then the charger may be faulty. If the voltage is too low then you may find that the battery does not charge fully or only charges when the laptop is turned off, however, a faulty battery or charging circuit may show the same symptoms. If the voltage is too high then the laptop will probably work correctly but it may get hotter than usual and or the battery may overheat and fail quicker than expected.

4. Everything may seem to operate correctly, laptop running and battery charging, then for no apparent reason the battery

may stop charging and or the laptop may turn off. This is often caused by the power plug that connects from the charger to the laptop failing. Sometimes the cable breaks where it joins the plug. This can occur if it has been sharply bent or is repeatedly been bent at this point. Generally wiggling the end of the cable will cause the battery to charge then not charge. Beware though this fault is often as a result of the internal laptop socket failing.

5. The laptop and charger may seem to be working ok but a high and potentially dangerous voltage may be present at the plug that connects to the laptop. Using a multimeter set to AC voltage measure between one connection (it does not matter which) of the plug that connects to the laptop (NOT the mains plug) and an earthed point, this could be any metal object connected to electrical earth. There should only be a very small or no voltage present. If a voltage is seen then the insulation inside the charger may be failing or has failed and may eventually let mains voltage enter the laptop! For safety you should immediately replace the laptop charger.

Laptop chargers are relatively cheap and should be immediately replaced if you suspect a fault is present as if ignored may cause an expensive laptop failure. If you use the manufacture's original unit the tip should exactly match the socket inside the laptop and generally they are smaller than the universal charges.


Graham has had many years experience repairing defective laptops, netbooks, notebooks and repair USB drives; specialising in fixing motherboards at component level for Laptop repair is always difficult but is very rewarding when an obscure fault is located and fixed.

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Have a question for Graham?

25th May 2014 12:19am
when i connect my charger to my pc it sometimes says plugged in but not charging i can use the AC but my batteries are not being charged but sometimes it works well. but new thing started yesterday it was working fine but suddenly my laptop shutsoff it wouldnt start for some minutes and i turned it on and it happened for second time?? what caused the problem is it my charger or my Laptop ??
4th June 2014 6:07am
sounds like a power supply unit issue or either a bad charger: battery may also be bad depending on your charging cycles that can diminish you battery life . more or less check the psu as well as the output of the charger.

Vincent Putelli
15th June 2014 8:23pm
I believe the issue is with the laptop, I have tried 4 different power supply pack on my laptop and every one of them the light indicator stops as soon as i plug it in the laptop. I then need to disconnect the power pack from the main and reconnected to the main for the light indicator to come back on the charger. If i used any of the 4 power pack supply with an other laptop they work fine. It seems that the faulty laptop does something to the power pack once plugged in. I cannot start up the ... Read More
27th June 2016 6:18am
I have same issue. However, first time when this issue happened the DC cable and motherboard got replaced and it was working fine almost one month and again same issue happened. Can you suggest why this is frequently happened with my laptop. Is this the issue of laptop , charger or Earthing ?
Kind Regards

30th June 2014 4:23pm
My laptop works fine with the plug in but the battery removed. If I insert the battery the laptop immediately shuts off. The battery is brand new. Any ideas? Thank you.

20th August 2014 9:45am
my laptop charger is 19.5V/4.62A/90W but when test it with a multimeter it shows 19.9-20 volt is it OK or faulty although my laptop is running normally.please clarify me the thing that is the problem with my multimeter or charger?

14th September 2014 1:58pm
My power turns on but not the screen. I take the battery out and unplug and leave for a week then it turns on again. I can use as long as I want but once it turns off it won't work
Again for a week or so....

Paul T
21st September 2014 8:16pm
Hi, I have a 4 year old 18'4 inch Acer 8390,g. It is now becoming very unstable and just switches off altogether sometimes 5 times In a row before starting up and being OK. My laptop battery is worn out and not holding charge for more than 5 mins and should be replaced.It works without any battery and AC power but is sometimes also unstable. The Power socket on the laptop used to get very hot and needed to be played with to work properly. That seems to trigger a switch off sometimes too. ... Read More

12th October 2014 9:32am
My laptop Acer aspire e1 510 only one month old.From one weak laptop off without warning at 40% battery remain always.When i tried to restart it cannot start. So i have to plug in again for charging after 5 min it start But it shows battery 5 or 6%.please help me.

26th October 2014 11:01am
Hey i wanted to ask something, is it possible for a Laptop charger to damage a battery, anytime I'm charging my comp, the system doesn't show that it's charging,but the charging light is on,and the percentage increases. i bought a new battery two days ago but after two days of behaving well, it doesn't charge at all, could the charger have damaged the battery?

6th January 2015 5:55pm
My laptop, (an Acer Aspire 5742 Series,) keeps shutting down without warning. It's usually after extended use. It could be a whole different problem, but it acts like it's overheating. For example, the fan starts to run as fast as it can, and even if I set the laptop on top of something so that it has good airflow, it still sometimes shuts off. This made me think maybe it has something to do with the power supply not being sufficiently cooled, but it happens constantly and gets really ... Read More

taiwo adenike
13th April 2015 11:47am
My question go thus, when charging my laptop, it normally display charging on the screen but the percentage never leave 100%. And when electricity went off, it took me not up to 5minutes to shut down. What might be the cause pls.

7th May 2015 10:11am
How to replace power ic of laptops

22nd May 2015 9:38am
i had an overload at my house and and my main fuse got breaked...i see smoke coming from my charger and i felt some smell too..but when i connected the charger it charges normaly...but its shocking to touch the charger tip..what should i do..

24th July 2015 3:57pm
Hello I constantly get BSODs in my Toshiba Satellite U405 SP2801, mostly after suspension mode recovery...

Most of the time I get BSODs from the Windows 7 file ntoskrnl.exe. I've checked the RAM with memtest86+ 5 times & didn't give errors, no viruses & tested with fresh Win 7 installs, I simply don't get what could be the problem & need help.

25th July 2015 11:52pm
My Chromebook is more than one year old, and recently, I began to experience trouble with the touchpad. The cursor would skip around - not simply go smoothly were it was guided by my finger. A website mentioned that sometimes the battery charger would cause that trouble, so I have to disconnect the charger from the PC to get the touchpad to respond as it should. I don't recall (or understand) what the reason is for this condition, but at least disconnecting the battery charger solved the ... Read More

29th July 2015 7:34pm
"Using a multimeter set to AC voltage measure between one connection (it does not matter which) of the plug that connects to the laptop (NOT the mains plug) and an earthed point, this could be any metal object connected to electrical earth."

How do I test this at home? I am trying to determine whether the laptop internal socket is faulty or the charger. 1-4 don't have been checked, so this is the final check to determine what needs fixing.

Vincent Mbogo
30th July 2015 2:05am
I bought two chargers from two different retailers with the required specs for my laptop.The problem is, when i plugin either of the chargers to charge my laptop,they charge for a few minutes then stop charging but i can detect the current in the charger.Can you help me?

4th August 2015 4:24pm
Why would my laptop cause the whole socket system in the house to fail - the MCBs are triggered in the circuit unit, what would do this?

23rd August 2015 1:58pm
My laptop charger *seems* ok; the indicator light at the end of it (where it connects to the laptop) is lit blue. Sometimes lately, I have noticed that the brick becomes a bit heated... but then again, I have also noticed that with the laptop. The laptop indicates "plugged in, not charging". And the charging indicator light on the laptop flashes back and forth from orange (not charging) to white (charging). Mostly orange. There is one issue with the charger - the wires are exposed ... Read More

26th August 2015 3:24pm
Hi, laptop and adapter ar working nice, most of the time. But when my battery gets real empty... and I connect the laptop to the power-adapter the adapter switches itself off (green light off, after some seconds). After a period of rest the adapter will work again - but when I conect it to the PC it stops again. Got 2 adapters here, with same problem. Workaround is: switch of Notebook. And connect adapter. Then loading begins. If loading is at about 40/50% I can safely turn on the laptop ... Read More

30th August 2015 12:20pm
When my charger is connected to the laptop, it shows blinking orange light or a constantly remaining white light. and laptop is not turned on. In normal terms there should be constantly remaining orange light when the charger is connected. what is the problem with it? do I need to replace a charger

9th October 2015 8:03pm
Yday am found that ....when ma netbook put in shows charger connected but not it caused bcoz of failure of battery? Or charger?..when I give power to netbook it will b on......but when I take the power away its again shutdown

9th October 2015 11:54pm
Hi Graham!

I have a situation with my laptop. So I was using my laptop to program a circuit board and view its behaviour on an oscilloscope while all of a sudden when I powed my ICs on my circuit with a 5V DC supply, my laptop went blank and it hasn't turned on since. The indicator which shows when the laptop is charging doesn't glow as well. Could you tell me what the problem could be?

11th October 2015 1:28pm
My laptop dont turn on anymore when I switch it on it blink white light on power button for a second then nothing happen, but the charger light reflect , can it be power supply? If yes how do I solve it

Neeru Singla
31st October 2015 1:15am
When I connect my charger with laptop, it shows
"plugged in ,charging" but charging is not taking place.It sticks at one point i.e 10%.Will anybody please tell me in which part i a getting the problem????

Despina Burgess
15th November 2015 11:36pm
my dell pc showed error message on all in one screen saying not recognising power adapter now screen flickers switches itself off this has happened twice in last 9 months I've change d adapter first time and error code went ,strange it's not later 9 months ,is it internal fault rather than power adapter ?thanks

22nd November 2015 9:54am
Great! Thanks for the information.

Adhar oli
14th December 2015 9:39am
I have of hp brand of model hp elitebook 6930p. when i was charging my laptop my charger got damaged suddenly. it happened during charging from that day i ve changed my charger for three times. they also damaged like the first one. now my laptop is not charging. it donot opens. when i consult my problem to the mechanic one told that your connector has been damaged and another claimed that your charging has been damaged. what may be the problem???
please tell me

David Mensah
8th January 2016 6:28am
My laptop suddenly shutsdown when am playing PES 15 or FIFA. But sometimes it shuts down when am watching movie..Please what is the problem is it the psu or the laptop for my power pack it gets very hot sometimes please i beg can i know why???

8th January 2016 7:06am
Please help,i plug in my charger from night till moring the battery fail to charge,i remove the battery to know what goes wrong,and plug in the charger,power it without battery it power on
somebody passworded my laptop without my consent what should i do with this two cases please bail me out !

Tim Rouse
10th January 2016 4:32pm
I'm having bsods and can't figure it out I've changed memory ; hard drive , os,could it be the motherboard ? Bsods are :it'll not less or equal ,whea, power failure, interrupt exception not handled I tried everything. ThankYou

21st January 2016 3:51am
Brilliant article! Thank you! I appreciate your work. You really described everything so clear and detail.
I have a question about certain UPS. What can you say about APC UPS? Is it good. I looked on [url removed by site admin], but I don't know how it recommended itself in usage! I know that Dell makes good one. Can you clarify me this topic!

29th January 2016 10:09am
please my laptop is not charging but when I touch any metal around or inside it I feel some electric shock but not charging no light is showing either

6th February 2016 9:17am
when i power up my laptop it wont start only battery status indicator led glows .can you please give me some suggestion how to fix it???

15th February 2016 8:46am
Very useful information! Thank you a lot! My cat has bitten my laptop power supply and I have ordered one that worked good, but a week ago the laptop stopped charging and I thought the problem is with power supply. But I followed your tips and understood that the internal battery is broken! Thank you for this article.

16th February 2016 12:58pm
When ever i power my PC the led comes in short time it goes off, i try washing the motherboard, still the same, what else can you support me?

David Maxwell
21st February 2016 2:57am
Howdy, thanks for the great write up. I'm still a bit confused on the results I have gotten when running the tests on my laptop mother board and its adapter. When testing the laptop power adapter (from the end plug that would normally fit into the laptop DC jack) I get a fluctuating reading between 18.99 to 19.23. The back of the adapter reads it should be 19.5. When I test the power from the laptop DC connection (with the adapter plugged into it) I get a reading of 17.75 to 19.23 but ... Read More

4th March 2016 9:09am
my hp compaq laptop charger is not working,
after plugging and switch on; the laptop indicator wil blink for 4-5 seconds and it wil off .when i checked with volt meter it get charged for 4-5 seconds and no dc current flows after that, what could be the reason ,,could u tell me please ?

20th April 2016 7:29am
Hello, So I have a laptop Compaq presario cq57 when I push the power button, only the power on led light comes on, the rest..hdd off, fan not spinning and display not turning on,
please help what could be the problem?

umer farooq
28th April 2016 9:28pm
My laptop shows that charger plugin but not charging dell corei 3

5th May 2016 2:47pm
my charger works fine, even the charging light on the laptop illuminates to show that its charging, but when i try to switch on the laptop, nothing happens, i tried letting it charge, but still the same effect when i try switching it back on, please what could be wrong?

Obot Alfred
27th May 2016 11:48am
My laptop would not power on ac!
Laptop power on battery, show 0% available, battery charging but battery not really charging.
Is there a problem with internal power jack that feed the motherboard?
Is there a problem with battery charging ic?
Or is there a problem with the motherboard?

Manohar Rai
9th June 2016 1:54am
In my acer aspire laptop (5735z) some problem started 2 months ago. Laptop will start and stop un intermittently. And it will not completely come on and this start stop kept on happening. Then I did some research in Internet and found out that charger may be the problem. So i removed the cables and fixed back, it started working. But few days after same problem . Now i am run only in safe mode keeing the charger connected. If i disconnect the charger pin it will run. But i have one more ... Read More

19th July 2016 11:26am
Had my laptop on while charging, then the computer suddenly shut down. I heard a small pop come from the charger. The computer itself was not even warm but the charger was hot. Laptop was charged up to 50% when it happened but will not power on at all. The charging LED will not come on when plugged in.

I'm sure the charger is shot, that's pretty obvious. I want to know if the laptop is also toast... Is there any hope of getting it to work again?

27th July 2016 5:16am
My laptop suddenly turned off while in used, I changed the charger but it didn't come up, what do I do?

27th July 2016 5:20am
My laptop always make a beeping sound when turned on, what is the possible fault?

4th August 2016 11:02pm
My Toshiba Satellite laptop (2009) is randomly shutting down, in admin log I found kernel power critical error 41, all values are 0, sleep false (saw it only today)....the adapters are working fine as I have two adapters and two laptops and I have checked them. I got the laptop fan cleaned, applied thermal paste but I'm seeing this error now.
Is it internal power issue? Kindly help me narrow down the issue so I can get it fixed. :(

Charles Altair
13th August 2016 11:24am
My laptop starts to start. i.e. light comes on for a couple of seconds then the startup process stops.

Avinash kumar singh
17th September 2016 3:50am
I have lenevo g510 laptop. Whenever i turn it on, the power led will be on for 5 seconds and the fan will run too and dvd led also blinks but then it gets turn off. Kindly tell me what is the problem.

25th September 2016 10:32am
just want to ask you a question.
last night i came aware of that my laptop was hot on unusual places such as by the screen so i shut it down and left it off until this afternoon but nothing happen. i have a sony vaio so i tried the assist button still nothing. when i connect the battery charger the battery charge indicator flash
but that all. could it be that it is the powersupply had failed? i hadnt take it to a repair shop yet.

4th October 2016 8:53am
My hard drive is reporting high command timeouts, and I've been told this can be from a faulty power supply. How can I tell where the issue is and is that's the problem? I don't quite follow what you explained in the article.

9th October 2016 11:39am
I have a very weird problem with my laptop, it is acer aspire 4736z, Dual Core Intel processor. 1) it will not turn on with battery, when it is on battery the power button light is lit, cpu fan runs but no other sign, no screen light nothing. However it used to run on AC adapter. I have changed many different Acer Batteries but no luck. 2) After few months of running it in ac main with adapter(charger) not it will not start up at once. the power gets automatically cut of at the time of ... Read More

18th December 2016 12:24pm
my laptop charger got exploded and I went and bought new charger but when I plug it and switch the laptop on it shuts down after some seconds please help me what could be the general problem

28th December 2016 9:17pm
I have a laptop that has a problem with the electrical adapter. I have tried two different adapters. One adapter almost boots the machine, but just before the hard drive should boot up, the system halts. I then get a blinking LED message. The other adapter allows LED Indicators to briefly illuminate and then they go dark. All that will operate is the cooling fan and the DVD Device. It seems as though neither adapter is providing the proper voltage for the machine to boot fully, especially the ... Read More

14th January 2017 10:42am
My Accer aspire does not power on either showing any sign of being working is it because power supply failure any one help pls

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