Laptop charger overheating repair, which should I replace

Thread Starter

ransaraw

Joined Oct 8, 2017
1
Skip to third paragraph if you don't want to know how it happened!!!
So yesterday I was playing a game (Dota 2) on my laptop. I had chosen the power profile to high performance in windows and plugged in. I was playing for like 3 hours and then suddenly I got the notification from windows that the battery is below 10% and to plug in. Then I checked the power adapter (charger) it was not warm as it usually is and even if it is plugged in correctly the laptop won't charge. So I tried another charger and it worked it charged completely to 100%.

I have some knowledge on electronics and electricity. I've studied physics for advanced level examination. And I'm a hobbyist, I experiment arduino based projects etc. And I have very good soldering skills too.

Later I tried my charger again. And it worked but for like two minutes and then it stopped working the charging led turned off.

So I opened (with a chisel and a hammer) the charger removed its coverings etc. Then I tried it again without the battery this time I could boot up and open another game which is not a very demanding one(blur) and I could play for like 10 mins it just turned off. So it crossed my mind that these type of things happen with overheating problems. So I set up a small dc pc fan to cool it. This time I could play for like 2 hours without any problems and I shut down the laptop to ask you this.

So this has got 2 transistors I guess maybe schottky diodes and one IC with 4 pins in a package similar to to-220 package. And at the bottom I've got an IC which is a pwm controller(found it by googling) part no dap108f.

So can you help me I think it's just a small fix and I'm pretty sure that it is caused by overheating I am linking some photos to help you guys.

Please just tell me anything you know about this thanks in advance.

https://drive.google.com/file/d/0B_H2iDToMajJcF95NzI2eFNyVUE/view?usp=drivesdk

https://drive.google.com/file/d/0B_H2iDToMajJUERSUHhPcDZ5TjQ/view?usp=drivesdk

https://drive.google.com/file/d/0B_H2iDToMajJRmd3VlRMVkJoZU0/view?usp=drivesdk

https://drive.google.com/file/d/0B_H2iDToMajJenNqZnM1TXJob0k/view?usp=drivesdk
 

wayneh

Joined Sep 9, 2010
16,399
I'd say step 1 is to make sure the charger is actually misbehaving and not just underrated for the use it is getting. I agree it sounds like it's overheating. But why? It's not clear from your story whether the second charger was merely able to charge the battery, or was able to charge the battery and run your game at the same time, or if it may have had a different power rating.

The point of step 1 is that you're not going to succeed in a 'repair' if the thing isn't broken in the first place.

Step 2 would be to replace all the electrolytic capacitors, the ones that look like beer cans. They are the most likely component to fail from old age, and it's common for power supplies to die from bad capacitors. Your's hasn't fully died yet but may be struggling. The step2 repair costs a few dollars and it takes a little while to solder and desolder. This is trivial compared to any other repair you might attempt.

Step 3, which you can skip to directly by skipping steps 1 and 2, is to just replace the charger with a beefier one and forget about it. Step 3 is not a more detailed repair process. That's next to impossible without a schematic, an oscilloscope, and some repair chops. And you may still fail.

I think you might be asking about perhaps adding a heat sink? There is a cooling spray you can buy to precisely cool a selected part. With this you might be able to find your hot spot, and then maybe get ahead by placing some fins on that part. This seems like a lot of trouble to arrive at a band-aid solution that may likely fail very soon anyway when the failing capacitor goes tits-up for good.
 

Lyonspride

Joined Jan 6, 2014
137
Might be a faulty polyfuse, I come across these from time to time. They seem to have a habit of drifting away from their specified current rating, they'll work for a short time until they heat up and then they go very high resistance.
 

eyesee

Joined Oct 19, 2013
60
Does the charger have a power on LED?

I recently came across a Dell charger that would work intermittently. Turned out that there was a short in the output DC jack/cable.

With the power supply off, check on the output terminals for a short (VO - white, GND - black).
 
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