Samsung Notebook "no power"

[DanF]

System: Samsung NP350V5C

Problem is that, for a few minutes there's power, but after a couple of minutes the system loses power. Power LED turns off.

I've tried to replace the power adapters and eliminating the battery. What works (for a few seconds/minutes) is to disconnect the power connect it again (the power LED turns on again). The longer you wait, the longer it holds the power. If you had to try to disconnect and connect the power within seconds from the last power off, it will only hold for seconds. It even does it in BIOS, so it's surely not OS related.

Also, not sure if this is Windows 10 related issue, but the battery charge data seems to be incorrect (i.e. 8% charge - 3 mins to full charge).

Problem only seems to be affecting the system when it's powered on. When it's off, it keeps on charging (LED remains on).

We haven't tried replacing DC jack yet, cause we don't think it's related to it.

For some extra information, last month we've replaced the screen on this laptop.

 

[Pierre POMMIER]

This charging issue is not related to windows problem. It because of your battery connection or battery damaged. Try to remove the battery from laptop and check. Otherwise you have to bring the laptop to a specialist.

 

[DanF]

Battery or no battery, it still does the same as long as it's on.

This charging issue is not related to windows problem. It because of your battery connection or battery damaged. Try to remove the battery from laptop and check. Otherwise you have to bring the laptop to a specialist.

 

[Pierre POMMIER]

Let me know if this helpful. http://forum.notebookreview.com/threads/samsung-series-9-wont-turn-on.660015/

 

[DanF]

Unfortunately no, because this refers to those Samsung models that have the battery built-in, and they are referring to a guide that explains how a "battery disconnect" feature works by inserting a paper clip in an emergency hole.

The battery on this model can be easily removed, and I don't think it's related to the battery, for the simple reason that it seems to work fine when the system is powered off (i.e. LED light does not turn off).

Let me know if this helpful. http://forum.notebookreview.com/threads/samsung-series-9-wont-turn-on.660015/

 

[Daifne]

Otherwise you have to bring the laptop to a specialist.

You do realize that this site is filled with those specialists already (exclusively), including the person asking for help, don't you?

 

[tlaybourn]

CPU cooling problem? Fan, thermal paste etc

 

[DanF]

Unfortunately no checked temperatures and thermal paste was replaced as well. CPU temps fluctuate between 45C- 55C.

CPU cooling problem? Fan, thermal paste etc

 

[DanF]

There are 3 key factors here:

1. System is off > power adapter plugged in > Charge Status LED turns from off to orange (meaning the battery is charging) > system is powered on > After a couple of minutes Charge Status LED turns off. This obviously means that the system is not getting power anymore (and is only getting power from the battery).

2. System is off > power adapter plugged in > Charge Status LED turns from off to orange. No problems here, Charge Status LED is orange for ever (I will try to leave it overnight to see if it really stays on forever). This means, problem is only occurring when the system is powered on.

3. The problem also occurs when in BIOS. This means the problem is not caused by the OS. Also, battery or no battery makes no difference (other than that the charge status LED is green, meaning full charge or no battery is present). However, battery never seems to get to 100% (charge status LED doesn't seem to ever turn to green even though it's been off and charging for the past 5 hours. This could mean that the battery's time is up too).

User Manual:
http://downloadcenter.samsung.com/content/UM/201408/20140829115848083/Win8_Manual_eng.pdf

 

[DanF]

Same exact problem with the new adapter.

Let's explore this a bit more: what happened when you tested the computer using a different power adapter?



From what you've said so far everything points to the external power adapter cutting out after a few minutes of use, and letting it cool down makes it work again - the cooler, the longer. If the same behaviour happens with a different adapter then the computer's probably drawing more current than the adapter can handle and you should look for shorts or burnt bits on the computer's motherboard. If the replacement adapter works normally then the problems is in the original power adapter (bad electrolytics, faulty thermal cutout, or whatever) and you should just throw it away.

It's easy to get bogged down in nit-picking details, but most diagnoses can be done with an axe - split the problem in two, see which half it lies in, then repeat.

 

[jfm]

Easy mobo call

When you're scratching your head that much over a laptop, go motherboard !

 

[DanF]

In this case a motherboard replacement isn't worth the money. Motherboard cost including labour costs would only be around 20% short for a new laptop. Also, I'm not getting a motherboard if I'm not 100% sure it is it. There's 99% probability we'll end up with that motherboard in stock forever.

I suspect it's some components on the motherboard, but we outsource this work to third parties and wanted to check with you guys before actually going that route.

Not necessarily, but if you're happy to sacrifice a motherboard as part of the diagnostic process then by all means replace it. Don't be surprised if you end up with a second fried motherboard if it turns out to be something else that's causing the problem.

Sometimes it makes sense to swap components when tracking down a problem, especially if they're cheap and readily interchangeable, but installing a new laptop motherboard (one of the least interchangeable components imaginable) before you even know that the old one has failed seems lazy and wasteful to me.

À chacun son goût.

 

[DanF]

I hear you

We haven't tried to disconnect the screen yet, will do that soon.

[

So what happens when the screen is disconnected - failure, or no failure?

I need closure, dammit!

 

[Larry Sabo]

Recently, when I installed a new screen I damaged the video connector and thereby prevented the laptop from starting. Be sure to examine yours using a strong magnifying glass.

 

[DanF]

So, tried to run the laptop using the following config:

- RAM
- Keyboard
- Power button

Everything else was disconnected, including screen, all connectors (other than the cooling fan, keyboard, power switch), battery and so on.

Unfortunately... 15 minutes down the line it turned off unexpectedly. When we tried to power it on again, power button light blinked for a second and that's all. Tried again, this time not even a blink. This seems to be confirming that it's something to do with the motherboard. Also because the voltage can still be measured at this stage on the power jack connection to the board.

 

[Krynn72]

You are sure that the AC adaptors you are using have the same current output the laptop needs, right? (Sorry if this is beneath you, just want to make sure we're not missing something simple). On the laptop and AC adapter it will tell you the 19v and something like 3.42a. if the laptop needs something like 6a and you're only feeling it 3.42 then it would cause this sort of issue.

Otherwise, given everything else you've done I'd say you've narrowed it down to mb.

 

[DanF]

No worries at all about pointing this out. We all miss things at times, especially during stressful moments

Unfortunately, the power input requirements are 3.16A and both adapters output exactly that amperage. Now I'm hoping that it's not that the second adapter is also malfunctioning. I have a universal adapter, however for some reason it's outputting 15V when the matching pin is inserted, and this one needs 19V.

You are sure that the AC adaptors you are using have the same current output the laptop needs, right? (Sorry if this is beneath you, just want to make sure we're not missing something simple). On the laptop and AC adapter it will tell you the 19v and something like 3.42a. if the laptop needs something like 6a and you're only feeling it 3.42 then it would cause this sort of issue.

Otherwise, given everything else you've done I'd say you've narrowed it down to mb.

 

[Larry Sabo]

Also because the voltage can still be measured at this stage on the power jack connection to the board.

I think you've determined that it's a MB fault, however, I'm curious exactly where you measured the voltage, i.e., on the lead from the jack where it enters the MB, or a trace/pad on the MB fed by that lead? Just trying to eliminate the possibility of a faulty solder joint. Sometimes they have microscopic cracks/gaps that can't be detected with the naked eye.

 

[DanF]

The DC jack is like this:

http://thumbs4.picclick.com/d/w1600...A05AE-Dc-Jack-Power-Socket-Port-Connector.jpg

The pins shown bottom right of the picture are soldered into the board. I measured voltage on those pinouts. It was a steady 19V even when the charging status LED went off. I don't have means to measure amperage of the adapter, although I thing it's less likely I ended up with another faulty adapter (if the original one is even faulty).

As previously mentioned, I don't have the knowledge to read schematics and do component level repairs, although I'd love to learn to. What I hate about this is I was never able to find an efficient partner. Business wise, if the customer agrees I would have to outsource the job, other than that it's not worth replacing the board as it ends up costing almost as much as a new laptop. Also, from the customer's history, we've already replaced the screen (a month ago) and the hard disk (around a year ago). and a RAM upgrade (before that).

I think you've determined that it's a MB fault, however, I'm curious exactly where you measured the voltage, i.e., on the lead from the jack where it enters the MB, or a trace/pad on the MB fed by that lead? Just trying to eliminate the possibility of a faulty solder joint. Sometimes they have microscopic cracks/gaps that can't be detected with the naked eye.

 

[Altster]

Also sounds like the battery has developed a memory, ie - 8% charge - 3 mins to full charge.

I'd be looking for another (different battery) to see if the it will take longer to charge to a full charge.

And I agree with Krynn, sounds like it is directly related to a m/b issue. Sorry ;(

What class of computer is this? Business, Home, etc.? If it is a home class computer I'd be pusing the customer to spend more money on a business class computer - something that isn't going to go south shortly after it is "born."