AC/DC Power adapter
AC/DC power adapter as known as power supply or power brick converts the high voltage AC power from a wall outlet into the low voltage DC power needed for your laptop.
The AC/DC adapter provides power for the laptop and charges the battery. It’s very important to use the right adapter for your laptop.
If you are looking for a new adapter, you should check the following:
1. Your new adapter must have exactly the same plug (adapter tip) as the original one.
2. Your new adapter must output exactly the same voltage as the original one.
3. Polarity on the new adapter’s plug must be the same as on the original one.
You can find the output voltage and amperage on the adapter’s label. As you see on the picture below, my adapter outputs 19V-3.42A.
When you buy a new adapter, you can follow this rule:
The output voltage must be the same, the amperage could be the same or higher than on the original power adapter.
For example, if my laptop requires 19v-3.42A adapter, I can safely use 19v-3.95A adapter.
HOW TO TEST OR REPAIR POWER ADAPTERS.
Most newer laptop power adapters are sealed and you cannot repair them. If the adapter is dead, you’ll have to buy a new one.
1. How can you tell if the AC adapter is dead? You can test it with a voltmeter. On the picture below I’m testing a 15V adapter and as you see the output is 15.45V. It’s pretty normal and there is nothing wrong if the output voltage is a little bit higher but if you are getting 0V, the adapter is definitely bad.
2. If you accidentally damaged the adapter plug, you can replace it with a new one. Just make sure the new plug has the same size as the old one. Cut off the old damaged plug and solder a new one. You can search for a new adapter plug (adapter tip) here.
Laptop parts | Repair Man | 
December 26, 2008 2:51 pm
176 Responses to “AC/DC Power adapter”
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Pages: « 8 [7] 6 5 4 3 2 1 » Show All
December 15th, 2011 at 11:38 am
It’s 19V~4.74A
December 15th, 2011 at 10:36 am
@ Ivan,
Take a look at the bottom of the notebook. There should be AC adapter voltage and amperage mentioned somewhere on the sticker. Something like 19V~3.42A
Let me know requirements for your laptop.
December 15th, 2011 at 10:08 am
I would like to ask what may happen if for example my 90w power adaptor died and now I use a 60W one, the notebook seems to work, but can it damage the notebook?
thx
December 14th, 2011 at 12:48 pm
@ Shyuan,
Yes, it should work fine. Your AC adapter input is 100-240V ~ 2.0A and the cable is 240V~5A. The power cable has higher ratings and that’s the way it should be.
For the power cable replacement you should refer to the input: 100-240V ~ 2.0A 50-60Hz.
December 14th, 2011 at 12:22 pm
Hi, thanks a lot for replying me.
1) In fact, I already have a Travel Adapter (for global travellers visiting UK) with the info as below:
–
Max 13A 250V
–
I need to use my US laptop in UK for a long period, I am afraid that I shouldn’t use travel adaptor, hence I choose to change the power cord, is there such a thing?
2) And besides, what if I insisted to change the power cord (yes, it is the “cable between the wall outlet and your power brick”, like you said)? I found UK power cords in some stores just now. They shown me UK power cord which can handle up to 240V with 5Amp. So with this power cord 240V 5A, it supposed to be able to work with my power brick requirement right?
3) I also wanna ask, should I refer to the Amp in “Input: 100-240V ~ 2.0A 50-60Hz” or the Amp in “Output: 19V — 6.32A” when facing issue like this? By looking at your reply, I assumed that I should refer to the Amp in “Input” right? Correct me if I am wrong.
Sorry for asking so many questions, I hope you could help me on these. Otherwise, it is totally okay with me if you can’t comment on them.
Your help is much appreciated. Thank you.
December 13th, 2011 at 8:38 pm
@ Shyuan,
By the power cord you mean the actual cable between the wall outlet and your power brick, correct? I think any power cord can handle 240V~2A. Just make sure it has the same connector as the US cord.
Also, instead of replacing the power cord, you can buy an All-in-One Travel Power Plug Adapter for US, UK, EU, AU ($3 from Amazon).
You plug this adapter into UK socket and on the other side you have regular US connector.
December 13th, 2011 at 8:28 pm
Hi,
I have a laptop ASUS K53SV from USA. I wanna get a UK type power cord (without adapter as mine is very new) to replace the US type power cord. My laptop power adaptor shows the details as below:
—
Model: ADP-120ZB BB
Input: 100-240V ~ 2.0A 50-60Hz
Output: 19V — 6.32A
—
Which power cord should I get? Do I choose power cord which support 240V? And do I choose also Amp which is more than 2A or should be more than 6.32A?
Hope you can help me with this. It’s urgent for me.
Thanks!!
December 13th, 2011 at 6:00 pm
@ brad,
As long as voltage is the same, the laptop should charge normally with the 3.42A adapter.
I think you should be fine with the 3.42A adapter.
It’s like wall outlet. You have 120V~15A coming out of the socket. When you connect a TV which requires 120V~2A, it works normal isn’t it?
December 13th, 2011 at 5:25 pm
Will a 3.42 amp charger stop charging my netbook that originally took a 1.58 amp charger,or will it overcharge? It clearly charges from dead much faster getting the battery warm, which I would guess like a car battery, can cause slightly more wear by rapid charging. but lead isn’t lithium so I don’t know!
So I am unsure if I should unplug the charger when fully charged or leave plugged in. or get original specs charger of 1.58amp
I simply have a drawer full of old laptop charges and now have two netbooks with NO chargers.
December 12th, 2011 at 6:40 pm
@ Dennis,
Some HP laptops can use both, 18,5V and 19V adapter. Take a look at the bottom sticker and see if both adapters mentioned on there.
- if both 18.5V and 19V adapters mentioned on the laptop sticker, you can use both ( I assume both adapters have similar connectors).
- if only one 18.5V adapter mentioned, use only 18.5V, 6.5A, 120W, Positive polarity (for 17″ laptop).
December 12th, 2011 at 6:30 pm
@ seta,
I cannot tell without looking at both adapters.
Probably it’s OK to do under three conditions:
1. Both AC adapter have similar connectors.
2. Both AC adapter have identical voltage output and polarity on one adapter matches polarity on the other adapter (for example “+” inside the plug and “-” outside the plug).
3. Amperage on the ThinkPad adapter is same or higher than required by Samsung laptop.
December 12th, 2011 at 5:52 pm
@ Scott,
As I mentioned in the previous comment, there is no limit. It must be the same or higher, that’s it.
December 12th, 2011 at 5:51 pm
@ Eytan,
There is no limit. It just has to be the same or higher.
For example, your laptop required 19v-1.58A adapter. You can use 19v-3.95A, 19v-4.74v, 19v-8A, etc…
You just have to make sure the power plug shaped the same as the original one, the polarity on the plug is the same (for example + inside and – outside) and the output voltage is the same.
Technically, yes. But I personally don’t like and recommend universal adapters.
I would suggest buying the original one even though it’s more expensive.
December 12th, 2011 at 3:55 pm
@ LoveSiee,
Yes, the logic board inside the universal AC adapter has switchable voltage. There should be a switch on the AC adapter where you can set correct voltage.
There is a small transformer inside the AC adapter which converts hight voltage AC power into low voltage DC power. Normally you don’t repair failed AC adapter, you replace it with a new one.
December 12th, 2011 at 3:12 pm
@ Robert,
I think your problem is not related to the AC adapter. You said the laptop shuts down after 10-15 minutes and this sounds more like heat related issue.
Take a look at the cooling fan while the laptop is running. Can you see the cooling fan spinning? Does it work at all?
You said the fan was replaced but maybe they forgot to connect it?
December 12th, 2011 at 6:35 am
The original adapter for HP DV4-2160US is 18.5V, 3.5A, 65W, positive polarity (output). I have two other extra HP AC adapters. Which one I can use:
1) 19V , 4.7A, 90W, Positive polarity
2) 18.5V, 6.5A, 120W, Positive polarity (for 17″ laptop)
Thanks,
December 8th, 2011 at 3:15 am
Hi,
you kind of answered this question in an earlier comment/reply, but I wanted to clarify.
I just bought a Samsung 700Z5B from the US, but I live in France.
I wanted to switch the power cable from my old laptop (Thinkpad T40)with my new laptops, just so I can plug it into the wall without using a plug adapter. Is that ok? it is the same 3-hole type that plugs into the actual AC adapter.
thanks
December 1st, 2011 at 1:55 am
Hi,
When replacing a laptop power supply, assuming the voltage is identical (19V) – how much higher can the amperage be?
The old adapter’s specs are: 19V, 1.58A, 30w
the new “universal” adapter, using the 19V setting, will supply “5A max”
can I use the adapter? what does “max amperage” mean?
Thanks!
November 30th, 2011 at 9:14 am
Hi,
First of all – your tutorial is excellent! informative, clear and easy to read and understand.
There’s one thing I don’t understand: When buying a new adapter, assuming the output voltage is identical (to the previous, now-dead, adapter) – how much higher can the amperage be?
I have a Dell Mini 10 and the second charger just died. The specs are: Input 100-240V, Output 19V, 1.58A, 30W.
Can I use a universal charger using the following setting: DC output 19V 5A ? (Between the two values is an odd ‘sign’ – a solid line, with a dotted line underneath it)
The complete settings of the (Universal AC and car) adapter are as follows:
AC Input: 100-240V~ 1.8A 50/60Hz
DC Input: 12V 15A
DC Output: 12V – 5A Max
15V – 5A Max
16V – 5A Max
18V – 5A Max
19V – 5A Max
20V – 4.5A Max
24V – 4.5A Max
USB Port: 5V – 1500mA Max
Thanks in advance for all your help!
November 28th, 2011 at 6:38 am
Hello there ! Thank u YOU ! Such an informative blog ! I wonder what is actually happening, which part is damaged when this universal adapter is stop working, no explosive sound inside the adapter and the laptop shut off, because the volt of the universal adapter is 19V, needed 19.5V. Could u explain it for me, im not a pro and had no idea whats inside the adapter, but I couldnt help myself until I understand & learn. Annnd.. Is it logic to have switchable voltage??? I mean this universal adapter can switch from 12V to 25V 0__o???
November 23rd, 2011 at 5:51 am
In my Compaq presario V4000 laptop there used to be shut down ater 10-15 mts use. Batter is old and takes 4% charge, but I use the laptop with AC adapter. The problem was diagnosed to fan and was changed but the problem persists.When it works, if I click on the power meter it says AC power on and batter 4% charge. The laptop should run with AC adapter and as such is the problem with the adapter?
November 19th, 2011 at 11:00 am
thanks mr Repair Man!
November 12th, 2011 at 9:40 am
@ MRSA,
Just google “Asus A8LE/Z99 adapter” and you’ll find it.
Also, new adapters for Asus Z99 laptops available on eBay. There shouldn’t be any problem finding it.
November 4th, 2011 at 4:43 am
Hi!My cousin gave me his laptop because he bought a new one. Though the problem is that, the battery and the laptop adapter was borrowed by his friend a few weeks back.
Now, I’m planning to buy a new battery and a new adapter. But the problem is this, I don’t have a clue what type of laptop adapter and battery to get. It’s an Asus A8LE/Z99 laptop. Underneath the laptop. this is what I found +19V 3.42A 65W
TIA!
November 2nd, 2011 at 4:24 pm
@ Bob Sherman,
Probably it will work but it might take more time to charge the battery. Or the battery will not charge at all.
Some people say that using underpowered AC adapter might damage the motherboard but I don’t know for sure.
I would use 6.32A adapter.
By the way, check label on the bottom of your laptop. Does it require a 6.32A adapter?