I used the wrong AC adapter for my laptop (y470p) , now it's dead and I'm trying to find out what was damaged.


Dec 30, 2014
When I was travelling, I used someone else's charger (19V, 2.34A) that had a far lower amperage than what my original charger was (19.5 VDC, 6.15A). The computer kept rejecting the charger, with the battery light flashing orange and the battery refusing to charge. To get around this, I powered off the computer and plugged the charger into my laptop so it would be forced to use the charger. Surprise, Surprise, the laptop suddenly powered off when I tried to run it off of the weaker adapter (without a battery), and wouldn't charge or power on even with the right adapter.

I searched for troubleshooting a blown internal power supply fuse since that's what I concluded the problem most likely was, and found nothing that helped me at all. I did find a thread with my exact problem: http://superuser.com/questions/509898/laptop-motherboard-shorts-when-connected-to-adapter , but it didn't have any information that was helpful to me, and I don't have any special equipment to test the wires/fuses. Is the main board dead, or do I still have a chance to fix the issue with it?

I'm attaching a picture of the main board where the AC adapter jack is, because I'm not sure if I actually blew a fuse or resistor, and I'm not too experienced at spotting things like that.

Picture of the board facing upwards: http://i.imgur.com/dMZL5sk.jpg

The connector with 4 wires attached to it is the AC Adapter jack.

There is no fuses you just swap out on a laptop, its all integrated circuitry in the laptop. Flat out it is not designed to be repaired.

If your computer does not work with original adapter and battery removed then you killed the motherboard

If you had a masters or phd in electrical engineering, and somehow got a full circuit diagram of the motherboard from the OEM then you could find and replace the blown components (assuming they are available for resale) but outside of this fraction of 1 %, there is nothing you can do.
It is not like there is accessible documentation on the board, and even if there was you would need advanced knowledge to be able to find/remove/replace the component.

Hopefully this will serve as a lesson to you for using what you already knew was a bad power adapter.


A little surprising actually, as long as it was wired correctly for polarity it should have just charged more slowly. If polarity was reversed and you kept insisting on powering it up you probably blew out a reverse bias diode during the internal power supplies POST.

I wonder if you just triggered some failsafe, have you tried getting at the CMOS battery and removing it for a few minutes?

Voltage input circuits aren't as complicated as you are making it out boosted. Discrete components are readily available from many electronics suppliers. These days the surface mount soldering can be quite tricky, if not impossible without the right equipment. I simply have a background in high school electronics shop class and can get by. PHD or EE degree not needed.

True I did go overboard.
The generic resistors, diodes, capacitors, etc would be easily obtainable.

The fact that the OP wondered about changing out a resistor (which would have had no problems with LESS power then it was designed for) shows that he has very low knowledge on electrical circuits. I just did not want to give the OP false confidence in isolating the issue with very limited knowledge (and from the sounds of it the OP is not experienced in even checking continuity or voltage with a multimeter).

Good suggestion on resetting BIOS


Dec 30, 2014

The CMOS Battery is soldered to the main board. Looking for more info on the board before trying anything.

Also, no need to be condescending boosted =]
The battery should be removable in some way, never seen a motherboard that has a non-removable cmos battery.

My appoligies if I seemed condescending, I did not mean to be insulting (hell most people don't even comprehend that those volts/amps mumbo-jumbo mean anything). I was just stating that you are trying to do a level 6 job without even level 3 skills.

For the record I can build simple circuits like a circuit of a couple relays, resistiors, and diode for a wifi garage opener with a raspberry pi, but I myself am not knowledgable enough to figure out what component was bad, nor good enough at de-soldering to remove tightly packed together components from a motherboard. When it comes to electrical components I am just smart enough to comprehend the basic concepts, and to know when something is over my head. Now I have diagnosed enough fried laptops to know firsthand what a bad power adapter will do (at least your board is not charred brown), and I know that there is not some easily replaceable part that you just swap out.
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