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System is an Asus N53S laptop. For several months I've been having the standard problem with a flaky DC plug that doesn't work unless it's positioned just so. Just to make life more fun, the battery no longer holds much of a charge, so the system is pretty much useless unless its plugged in. Being short of money, I've postponed fixing either problem.

Now suddenly the power supply is totally nonfunctional. If the power supply hasn't been used in a while, I can plug in the AC end and see the light go on. As soon as I plug in the DC end, the power supply light goes out and the charging light on the laptop never comes on. Disconnect the DC cable, give the power supply a few minutes and its light comes back on.

My first thought is to run down to Office Depot and buy a generic power supply. (There's one that officially supports my model laptop.) But suppose the power supply is fine and it's all the DC socket? That means waiting a whole day for the repair shop to open (of course this had to happen on a Memorial Day weekend).

So which of my bad choices is least bad? Should I spend $40 I can't spare on a new power supply, or should I lose a day's work that I can't spare either and wait for the repair shop to open?

(Yes, I know my situation is too specific, but the basic problem is general enough.)

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The finicky connector might be a separate issue. If the laptop is more than around 3 years old, the problem could be the battery, which could be at the end of its service life. One mode of failure can cause it to act almost like a short. It won't charge and it also draws heavy current, which causes the thermal overload protector in the charger to disconnect until it cools down. If the battery is old, I would start there (worst case, you'll have a spare battery for backup or longer run time). I've had terrible luck with 3rd party replacement batteries; I would pay more for the manufacturer's. –  fixer1234 Apr 12 at 23:09
I'd repair the DC connector first, since you know that needs to be done. –  David Schwartz Apr 12 at 23:37

2 Answers 2

Try to remove the battery and test PSU without the battery inside. Great resistance of almost dead battery cells could have created the problem here.

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I was going to suggest the same test but for the opposite reason. One way batteries fail is to develop a short. That would create an excessive load on the power pack and cause it to shut down (the symptom seen). But the suggestion would be the same. If the problem is the battery, the system should work normally on the power pack when the battery is removed. If the laptop is on the order of 3 years old, it could well be a dead battery. –  fixer1234 Jan 1 at 6:34

Ok that is quite difficult to diagnose. The fact that the supply needs several minutes to recover, might suggest that the problem is on the power supply side. Usually the LED should react faster. This, however, can be misleading. If you have some sort of short circuit on the Laptop side, your supply might get hot or another protection mechanism sets in. Did you try to provoke this effect be fiddling around with the faulty connector (open circuit)? Does the supply get hot? A tricky test would be to put a fake load, but that requires that you have some electronics equipment at hand (at least some resistors with the right dimension).

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