How To Check If AC Adapter Is Dead

AC AdapterAC Adapter or Alternating Current Adapter is a device used to convert standard wall outlet electricity coming from electricity line or any auto voltage regulator (AVR) or UPS. This is used commonly in any portable devices like laptop, notebook computer, notepads, and smartphones. This is used also in other devices or machines that don’t have primary input voltages like in other thin computers or branded computers. This adapter is a switch mode power supply that converts electrical power from higher voltages down to regulate direct current voltages or called as AC to DC once you plug-in in a wall outlet and turn your device on.
How To Open AC Adapter
If this device will damage or have abnormal functions, commonly “no power”, you will wonder “how and why” it happen or how it happen. There are common factors in the cause of the problem, might be over voltages or fluctuations coming from the electrical line or voltage regulators, over temperature inside the devices that causes malfunction of electronics components, shortages either inside the components and through the voltage regulator.Adapter Circuit Parts
So here in this post, I will let you know how to check it internally or inside of this device, where and what components should be checked. But this procedure needs a basic skills in electronics and how to use VOM and test electronic components use in it.Adapter Electronic Parts
  1. SYMPTOM: The machine or a device doesn’t power-up, no lights at all, nothing on screen, no moving parts once you turn on.
  2. PROBLEM: No Power
  • Unplug the AC adapter in your device of machine.
  • Open the cover, if you find a screws at the back uncrew it, and unlock the clip using the rounded part of a twizzer. (See the 2nd post image above)
  • Remove the circuit board after you open the cover.
  • After you remove the circuit board check the primary circuits.( see the 3rd post image here)
  • Remove the electronic parts I mention in 4th post image, the bridge diode, transistors, fuse, and filter capacitor using the soldering iron.
  • Test it one by one using multitester(VOM)
    1.  FUSE- Normally have a resistance once you check using multitester. If the device has no power commonly this part is damaged and don’t have resistance once you check it. Replace this with correct value.
    2. BRIDGE DIODE- This part is used to rectify AC voltages to direct current or DC, normally this part can be checked using VOM that has a forward and reverse bias, this part has a four diode peak as one or have a four junctions. If this is normal you can check the positive and negative in the four pins of this part. Commonly, if the fuse is blown this part also is damaging.
    3. TRANSISTOR- This part is used to trigger, switch, or regulate current voltages in the primary section of the circuit. This part have a 3 pin assign as base, emitter, and collector. check if this 3 configuration present using the forward and reverse bias of your tester. Another type of transistor use of this device is the FET transistor, it has also 3 pins as gate, source, and drain. You check by finding high resistance and low resistance through forward and reverse bias of the gate, source, and drain channel junction. Check here in this link:How To Test JFET Transistor  
    4. FILTER CAPACITORThis part is used as storage of the current voltages in the primary section of the circuits. It acts to store large amount of voltages coming from the input source voltage, like 400 AC voltages and rectified it using the diodes. This can be also damage in a long time of use, this usually damage through high temperature because normally this part has a resistance temperature up to 150 degrees. You can check this using capacitance tester or Multitester by checking the resistance, whether it leaks or weak.

  • To ensure that your AC adapter will become normal after repair, replace the damage parts with correct values.
  • Do not tampered of jumper the circuit boards, it will damage the device where it is used to power.
  • Do not test devices with other known voltage output or have it test the new repair AC adapter to the other device.
  • For more information on how to repair AC Adapter, you can open the site of Mr. Jestine Yong about electronic repair.
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AC Adapter or Alternating Current Adapter is a device used to convert standard wall outlet electricity coming from electricity line or any...
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About combinebasic

I'm a husband, a blogger and Biomedical Machines Specialist, also a computer instructor and technician and a crazy writer, I like to write and build blogs and avid fan of social media. I have built this blog just to help others through information. Follow us on Facebook and Twitter.

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