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.
July 12th, 2010 at 10:04 am
jide,
Do you still have the old adapter? Find the part number and google it. This way you can find the right replacement.
July 11th, 2010 at 6:06 pm
please can someone help me i have been trying to get an adapter with with the capacity of 17 volts or 16.8 volts with 2.0 ampaere can someone help me with the store or on how i can get the adapter
July 10th, 2010 at 9:11 pm
my adapter is a 65wc-ac adapter computer and i need to know how to rest it so mycomputer quits saying plugged in not charging and it starts charging
July 8th, 2010 at 10:40 pm
Charles,
If the plug on the adapter has the same size, it should be fine.
July 7th, 2010 at 7:16 am
hello, I have a new dell xps that replaced and old one. I want to use the old power supply at home because I use the new one at work. The volts are the same at 19.5 but the amps on the old one is less. Is this a problem? thanks
June 27th, 2010 at 9:03 pm
stacey,
The new AC adapter should work. The output 19V 3.42A is the same as on the original one, so it should be compatible.
Your problem could be related to one of the following:
1. The new AC adapter is not good. Try testing it with a voltmeter.
2. The laptop motherboard was damaged by the damaged AC adapter.
If the new AC adapter is good, here’s what you can try:
1. Disconnect the adapter from the laptop.
2. Remove the battery.
3. Wait for a few minutes.
4. Plug the AC adapter and try turning it on.
June 26th, 2010 at 8:08 am
i have a emachine d620 laptop dog chewed my charger so bought one of ebay its not working my old one is input 100-240v 1.5a 50-60hz output 19v 3.42a myy new one is 100-240v 1.8a 50-60 hz out put 19v 3.42a is it not working because of .5a any help wold be grateful im stressed
June 7th, 2010 at 5:39 pm
My daughter’s Gateway MT6707 has a power problem. The original dc jack area had smoke coming from it. I did not see any signs of damage. I replaced the jack with a radio shack brand. I read a short even now that I replaced the jack. I have unplugged the fan, dvd drive and wi-fi module but the short is still there. Am I on the right track for troubleshooting this problem? I’m about to the point of letting someone with the right equipment have at it to repair it.
April 17th, 2010 at 6:13 am
I use a little screwdriver I put the end on the midle of the power union.Make a little pouch and make his in all the side and thats it you can’t open them(push this first on the plg face side.
April 17th, 2010 at 2:20 am
Hello,
I have a power problem with my samsung M50 laptop. I can only get it to start with the battery installed and on AC power. pwer only lasts about 10 minutes before it drains. If I leave it off the battery charges ( led light turns from yellow to blue ) and I can re-boot again. I know I probably need a new battery as it is the original and I’ve had the laptop for 4 years. However I cannot boot up on AC power alone… led light is blue when off ( with Battery out) and plugged into mains when I turn it on it starts to boot up gets past the bios screen to windows logo then shuts off… led light turns yellow then back to blue.
I believe not all laptops will start on ac alone without the battery installed however I check with samsung and mine should. took it into a harvey norman and they checked with another ac charger and the same thing happened .. obviously something internal. I have tried several things I have read in blogs.
– wiggling the power input jack when starting up.
– checked the pins and plugs on ac jack and input to laptop
- plugging into several different power mains directly
- calibrating the battery
- resetting buy holding the power button down for 1 minute with all accessories removed ie cd drive,
Any idea’s or help is much appreciated.
Thanks in advance
April 1st, 2010 at 4:00 pm
That’s what I thought. I tried it the same way as testing the voltage with a multimeter but with the amps setting. I tried another adaptor again and it actually goes to zero amps because there is no load, so it is very strange how I am getting that erratic readings with the suspected broken one. It must be knacked. Even though, I would like to know why it does that if anyone knows? The readings were jumping very fast to different values from anywhere between 0.something all the way up to 3.something amps. Very strange.
April 1st, 2010 at 1:14 pm
Xer0,
How to you test the amperage? I don’t think you can do good readings until the adapter is loaded.
April 1st, 2010 at 1:06 pm
Hello. Is there an answer for Jay’s question? (the last one)
I have a problem with a laptops power too. The voltage is good but the amperage reading is very erratic and I would like to know if this is a clear indicator that the brick has had it’s day. I am sure it is but would like confirmation before buying a new adaptor as it could be a loose dc socket but I think I have fixed that. I was getting it to boot sometimes for a few seconds when I was holding the jack in the socket a certain way but not very often, so could be getting deceived if the current is maybe staying steady for a few seconds. Surely the amps reading should not be jumping about like mad when it’s not under load eh? Like Jay said aswell, I tried another adaptor and the amps seemed steady enough, although very low but surely that is because there is nothing drawing power from the brick, correct?
Thank you for any help.
March 7th, 2010 at 10:21 am
I have an External Hard Drive (EHD) that powers up and am able to hear it spinning. It seems normal by the sound.
Problem: After trying four different computers and trying four different data cables none of the computers can recognize the EHD.
Question: Could the AC Adapter be the problem?
I tested the output of the adapter with a Fluke 73 and it indicates 12.10 volts as it should according to the specs plate on the adapter.
However, in testing the amperage output, which is supposed to be 1.5A, the meter display does not show a steady output. Instead the digital display goes from 0 to up to a maximum of approx. 0.8 amps and flashing various other output readings in fractions of a second but never just a steady reading.
I’ve tested other random adapters lying around and none have that type of behavior. They just give a steady amperage reading, usually 50% or higher than that written on the plate.
Is it possible that this adapter is able to power up the EHD and sound as though it is functioning properly yet at the same time outputting defective, oscillating amperage and in turn cause an unreliable electrical signal to the computer disabling the computer’s ability to “see” the EHD?
I tried an Universal adapter that tested at 12 volts and displays 2.95 amp output. The EHD begins to power up then shuts down and continues to repeat that cycle, never steadily running. Wonder if the EHD has a “sort of circuit breaker” built in that works like a heat sensitive circuit breaker.
Normally devices restrict the amperage flow by what they actually use to run.
The simple answer is to buy another adapter, but is that really the problem?
Thanks, Jay