How to Check AC Adapter with Multimeter

If the laptop won’t power on when you using the AC adapter alone, maybe you have a faulty charger, you have to check it.

How to test AC adapter with multimeter:

To test the AC adapter, first you have to unplug the AC adapter cable from the Laptop.Measure the output voltage at the plug of the AC adapter cable. See the following figure:



Output voltage for the AC Adapter in picture may differ from the one you are used. If the voltage is not correct, replace the AC adapter.

If the voltage is acceptable, check the power jack and the laptop motherboard. in most case the power jack fail or electronic component directly after power jack fail.

10 thoughts on “How to Check AC Adapter with Multimeter

  1. George

    The voltage output is unique to each model of laptop, but is usually 9, 12, or 16 V DC. If you look for a plastic stamp or sticker on your converter, it is required to have the output voltage stamped on that. Hope this helps.

  2. ginis

    Hi guys, a friend brought me Compax CQ71 without charger, i see it has a round charger plug with the middle pin inside but since i don’t have a charger will it start or at least charge up a battery it connected to 19V power supply?
    Or is it possible ti feed it 19V to motherboard to start?

  3. solon

    help me.. my l430 wont turn on.. when i attach either the battery or the adapter.. the power button only turn on for a moment (didnt press) then when i press it nothing happens.. just black..

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