Laptop help please! and rant ;(

Occasionally we all screw up. Yesterday, I destroyed the third most expensive piece of equipment I’ve ever owned in my life… and worse, it was a gift… I’m feeling pretty STUPID and depressed because of the whole thing… :weary: :*

Up to four days ago, I’ve never owned a laptop or computer. (most expensive thing I own is a MTB) Yes, I’ve been around computers and use them on a semi regular basis (if I thief time at work). I had plans for a few years now to get one but the money never made it a reality. A few days ago, a friend gave me one he has because it doesn’t work well. YES!! A FREE LAPTOP! :smiley: :smiley: The battery never took a charge and the AC charger had a short… (He knows I fiddle and fix a lot of things and have come to me in the past. He’s also well off and knows when to stress about something and when not to.) It is a samsung SF-310 notebook with an internal battery. The thing worked beautifully when it was on. QUICK start up, little wait to open programs and lots of programs… I was so excited!!

Typically, I unscrew things and forget what goes where, with this laptop, I researched how to open it, what the battery looks like etc and even wrote down and drew diagrams which screw goes where!! I made sure I wouldn’t screw this up!! Over a couple days time, I took out the battery and realized that it is not made up of cylindrical cells! sigh worse, the battery itself seemed good but the output/protection circuit was dead so even if I could fit cells in, it wouldn’t work. Eventually with some fiddling, I got the adapter to work perfectly ( it was the connection that was damaged not the adapter.) and eventually learn’t that the laptop could work without the battey connected! Yay!! :santa:

But the evil, impatient, non- thingking, subconscously self destructive part of me wanted to get the battery working so charged it up with a hobby charger connected it to the laptop and polked…… SICK There was a sizzle, smoke and that horrid smell of burnt electronics… I hoped for the best: that a trace was burnt but, on accessing the underside of the motherboard, i saw it…a little 8 legged &^*# IC with it’s life burnt to hell. CRY…. I wish crying would have helped but it couldn’t come… I feel so embarrased and ashamed (that I come to a bunch of complete strangers for help instead of facing people around me in the real world)…. :frowning: Facing this guy again would be so hard… I don’t lie to people that matter so will tell him eventually that I f&($# up.

So, is there:

  1. anyone or a friend or family of anyone with a Samsung NP-SF310 laptop home that’s dead or malfunctioning that you’re willing to send/sell me? (so I can change parts or hide my shame?)
  2. any way that I can change the motherboard?
  3. Any possibility of figuring out what the IC is, buying a new one and replacing it?
  • I honestly don’t care about the battery now so that is unimportant.

Picture of IC

Sorry. I swear the photos were bigger. (They are, I just don’t know what to do at the moment. ;( )


Here’s the PDF for the ISL6255 battery charger chip:

If you trace what pins go from the 6255 to that 8-pin chip, maybe you can “guess” what the 8-pin chip is?

Edit: Also, since you don’t really care about the battery usage at this point, maybe figure out how to just get rid of the battery charger chip, etc., and just run it on AC?

Hmmm... What happens when you try to turn it on when powered off of AC? (Note: I have no idea whether or not this is a good idea, it may make the situation worse, I don't know)

Going off of ohaya's research it looks like that chip is just used for the the charging/maintenance of the battery. My personal guess is that you somehow overcharged the battery when you charged it with the hobby charger, and this caused for the voltage to be too high for the chip to withstand.

ohaya, thank you for the document. :~ Sorry if I wasn’t specific enough. The IC that burn’t out is the one at the bottom of the image. It’s approximately opposite where the input of the battery is.

I screwed up by connecting the +ve output from the battery to the +ve output from the ‘battery protection circuit’ (etc) of the battery. I was thinking that like AC, the laptop would use what it needs instead of frying. :ghost: (the battery was charged to about 4.08V per cell.)

Now, even with the AC adapter alone connected, the laptop doesn’t come on. If I press the power button to turn it on, the button lights up for half a second then goes off again.

Thank you everyone for any input.

if possible, could you get as much of the letters/numbers off the IC? now im not a genius with this stuff, but if you can get as much of the identifying marks off it as possible, it may help

Isn’t this the chip that got burnt (circled in yellow)?

Yes. The pdf you provided is gibberish to me so if that helped identify this, I’m sorry for not getting it H) <— not

Actually, I’m kind of confused about what happened, but anyway, look on the left diagram on pg 2 of the PDF, the square one.

That gives you the pinouts from that chip (there’s a small dot on the upper-left corner on the chip, which corresponds to the dot on the drawing in the PDF, that you can use to orient yourself for the pin numbers). Now, from the 8 pins on the 8-pin chip, try to find where each of the 8 pins connects to, esp. back to the bigger square chip.

If you can do that, it might help identify what that 8 pin chip’s functionality is, in case you can’t identify it otherwise.

For example, in the PDF, there’s also “typical application” circuits, so if you can trace the connections from the big square chip to the 8-pin chip, we can try go guess what that 8-pin chip is, by comparing to the “typical application”… maybe :)…

This is kind of like “reverse engineering”…

All I’ve figured out up to now is that it’s an AOZ chip. I’ve tried searching for the part number but no luck. (yet)

Nobody or nobody you know ever owned a Samsung SF310? :~

How about you remover that chip completely and try powering from AC!

I hope you can replace the IC (and that it will work afterwards!).

Ebay have replacement motherboards but they’re too costly.

Thanks Chloe. :confused: Fixing stupidity could cost more than a new laptop… I’ll look on ebay.
Sirius. The AC power doesn’t work anymore. The laptop doesn’t show that it has the adapter plugged in and when I try to power on, the power button lights up a second then off again…

Have you desoldered the small chip first?

It appears that the neighbour chip ISL6255AHRZ is a “Highly Integrated Battery Charger with Automatic Power Source Selector for Notebook Computers” (pinout here), this bold part is important for us, not the best angle on your pictures but it also appears that the small burned chip is connected to pins 12, 13 (via capacitor) or maybe pin 14, it’s hard to see and pins 15 and 16.

Now, it would be nice if you could probe the board an see what voltages you get but, since it works only for a second or so, it would be very hard to get any reading with usual/cheap multimeter, we will have to manage on blind here :slight_smile:

According to the datasheet VDD is 5V (that’s pin 13), Boot and Phase (14 and 16) is also 5V, now, LGATE (12) and UGATE (15) are tricky, I think they are used to signalise decision whether to use battery or AC supply, They can be 2.5V or 0V I presume…

BTW, when all this happened I don’t think you overcharge the battery (you certainly used charger for lithium batteries and they do not charge over 4.2v) it looks to me that battery protection (which you removed) actually was limiting the current and not the voltage, so the to high current (amperage) is what fried that little chip, little chip is just a support for the big chip it only helps in decision making and the big chip uses something like 500mA so, that small chip actually save the big chip :slight_smile:

Question is, how to bypass that small chip, datasheet for it would much helpful!!!

Tried removing the chip in a sane way but, it decided to break apart and disappear into the vast universe of my room… Luckily, I found a chip on the board that seems to be the same as the destroyed one…

Ugh. So the pics arn’t that helpful. I’ll have to go back in (really afraid I’ll ^*%# something else up) and check what connects to where on the big chip…

The dead chip possibly had 4822A BA0116 on it.

(sorry. Apparently I forgot to put the pic with the IC i found on another part of the board that might be the same as the dead one.)

Sorry for your loss. It will make you stronger.

In case it helps any, these guys seem pretty confident they can fix you.

Or, Aliexpress has a whole new MLB for an awful lot more money.


The 8-pin IC marked 4822A is dual N-MOSFET in 8 pin package.

datasheet - AO4822A

Rated for 30V 8A

here you can find 5 chips for 3.95$

At least any dual n mosfets rated 30V ~8A will compatible.

Pavithra_uk!!! You might be my hero!! (sorry for the lacking responses guys. I gave up on the repair. :frowning: )

Got the chips! Soldered one in place and nothing changed… :frowning: Removed that one and soldered another in place and the same thing… All I can add is that when power is conected, the new chip gets HOT. I feel the heat through the other side of the board… So either the chips don’t work, something else is fried or something got messed up when I took the laptop apart… Sigh.

I tink that power path from that chip shorted. this could be reason original chip to fry.

can you post more closeup photos ? I will help you