Laptop not booting - strange AC adapter behavior

Mogget128723

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May 13, 2011
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Yesterday, I was gaming on my Asus ROG G51J, when it suddenly powered off with no indication of a problem. (this wasn't a heating issue; the cores were all well below their limits) Following the unexpected shut down, I was able to turn the computer back on after disconnecting it from the AC adapter. Once the computer was booted, I plugged the adapter back in, but noticed that the computer didn't seem to notice, and was operating on battery power. When I switched outlets in an attempt to resolve the problem and plugged the computer in again, it immediately died for a second time. Following that, I wasn't able to get it to boot again, with any combination of adapter and battery.

Since then, I've opened the thing up and moved my hard drive into my older Toshiba chassis, but I've also noticed some interesting behaviour on the AC adapter's part.

I'll grab the loose adapter, and plug it into the wall. The power light on the adapter's box turns on, but then when I plug the other end into the Asus, it turns off immediately, and doesn't come back until the adapter's been disconnected from the wall, then plugged in again - effectively, power cycled.

To me, this looks like a failsafe thing - the adapter turning itself off because there's a short on the computer's end, but I'm not sure.

What do you guys think - is my Asus toast, or could this be a freak problem with the adapter itself?
 

Mogget128723

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Yes, I did mention that I tried all combinations of adapter and battery.
And yes, this is the original adapter. I never use universal adapters on anything that costs more than ten bucks.
 

kitsunestarwind

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The only time the Adapter will do that is because
A. charging circuitry in the laptop has a fault or short
B. Adapter has a fault / Has failed

Simple way to diagnose is get another adapter (either buy one or borrow one from someone) If the other adapter works fine, Your adapter is toast, If it does the same things your laptop has the problem
 

Mogget128723

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Hm, was hoping to try and diagnose this without spending any money, but I suppose spending $20 on a new adapter is better than spending $1000 on a new computer, right?

Oh, one extra tidbit of info: I found a voltmeter, and the adapter is putting out 19 volts, just like it's supposed to. It only acts wierd after it's connected to the laptop.
 

rdc85

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Usually if the voltage is stable and voltage as it supposed, likely the problem within the laptop. Since we using only original it still within warranty covers.

If it still under warranty try to claim it before testing using new adapter
If it not under warranty then trying new adapter won't hurt........
 

Mogget128723

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Good to know - thanks.
Unfortunately, the warranty's long gone - the machine is a few years old, and secondhand. But hopefully, I can find a comparable universal adapter to test whether the problem's in the cable or the machine itself.
 

I would hold off on buying a new power adapter just yet. If your power adapter is putting out the 19V, your problem is very likely a broken power jack. is a very common problem with virtually all mobile devices, it's from being plugged in and unplugged a lot. I was unable to find your exact model vid of replacement for it but this may prove to be helpful.
http://www.youtube.com/watch?v=ZHJeM1zfe2A
Any shop able and willing to do the replacement will usually not charge more than $100 and should guarantee their work.
Google "Broken Power Jack", you will find how to replace it yourself, who will replace it for you and also (and most important) how to determine it is a broken power jack.
I would think it would be worth it to get it fixed if that is the problem.