Power adapter, battery, wall socket?

October 27, 2006 8:28 PM

Help me understand/explain anomalous laptop power adapter and/or battery behaviour. Why would it be dead, then fine? Why would the system crash when it should hibernate?

Today when I came home from work my acer laptop had a dead battery (would not even boot to bios) and the light on the power adapter would not come on when it was plugged into the wall.

I took it out of the wall socket it was in and tried a fan in the socket, the fan worked fine. I took the adapter to another room and it still failed to come on. This happened once before when the power adapter overheated, so I ignored it for a few hours leaving it unplugged.

Now the adapter is lighting up and the laptop is therefore coming on and charging the battery (shows 5%).

My question is this, why would the power adapter crap out completely for a few hours and then be operating normally? Also, why wouldn't my laptop successfully hibernate as its supposed to (and normally does) if I leave it alone and the battery starts to die? Should I be worried that I need to replace my power adapter and/or battery?

posted by tiamat to computers & internet (6 comments total)

Probably an intermittent connection inside the power brick. You'd be well advised to get a new one.
posted by Steven C. Den Beste at 8:34 PM on October 27, 2006

I hope it's something as simple as that, but the brick itself is in great shape as are the external connections. Although the system is a year old I've tried to treat it very well.
posted by tiamat at 9:11 PM on October 27, 2006

My question is this, why would the power adapter crap out completely for a few hours and then be operating normally?

As Steven said, intermittent connection. This kind of stuff is too complex to diagnose and too cheap to fix for any tech to look into further. Maybe some connection somewhere inside the power block is overheating, or some microelectronic component is beginning to fail. Check the connections going into and out of the adapter power block. Maybe they were loose and by unplugging the adapter you put them back in contact with the block. If that doesn't fix it, replace it.

Also, why wouldn't my laptop successfully hibernate as its supposed to (and normally does) if I leave it alone and the battery starts to die?

Who knows. I had a similar problem once when dealing with a bad adapter just like yours. The computer detected that it was plugged into a power source, but it actually wasn't running off that power, it was running off the battery. (I think maybe the power supply wasn't supplying enough voltage, so it ran off the battery, which could supply it. Or something.) So, to put in in layperson's terms, the computer wasn't watching the battery level, and ran out of juice without shutting down.

Should I be worried that I need to replace my power adapter

Yes. Try a different power adaptor. If that doesn't do it, the power connector port in your laptop may be loose. Sometimes the power plug gets yanked around when it's in the laptop, damaging the socket. It would work/not work if you jiggle the cable around near the socket. If this is the case, hope it's under warranty.
posted by Brian James at 9:14 PM on October 27, 2006

When I had similar symptoms (dying when hibernating, refusing to charge, losing charge) I took my iBook to the Apple Store and the tech told me that the battery needed to be replaced. He said that batteries are usually good for about 300 charge cycles, so if you've had it around a year (also how long I'd had mine) and charge it around once a day, you're probably due for a new one.
posted by chickletworks at 9:55 PM on October 27, 2006

I hope it's something as simple as that, but the brick itself is in great shape as are the external connections.

That doesn't mean there isn't a cold solder joint inside or some other form of marginal connection on the regulator circuitry inside. It's also more likely to fail after it's been plugged in a while and heated up, as resistance increases with heat and things expand and potentially make less contact. That's certainly something supported by the fact that once you unplugged it for a few hours it started working again.
posted by phearlez at 8:44 AM on October 28, 2006

I've had similar power/startup problems in the past. Seems like it was on very hot days when the thing was getting some sun while I drove around.

I think I whacked the laptop a few times (gently) and pulled out the battery and put it back in -- then whacked it again. Seemed to work. Perhaps just waiting/cooling did the real work as phearlez explains

Unscientific evidence, of course.
posted by powpow at 12:12 PM on October 28, 2006