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.
Need spare parts for your laptop?
If you are looking for spare parts for your laptop you can find brand new and used parts here. Just search by the part name and laptop model.
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