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Laptop damaging the ac/dc adapter or coincidence?


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#1 Bt60SA

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Posted 15 July 2014 - 01:52 AM

Normally, when I plug in my laptop, a light glows on the front to show it is either plugged in or charging (AC) (whether it is on or off). Last week, I plugged it in and this did not happen (the laptop is from Feb. 2013). It is a Toshiba L855. i7. 75V power. Uses 19V DC from adapter. Basic memory and hard drive. No peripherals were attached at the time. USB ports and such still work.

 

When I opened the lid to turn it on, it worked fine on battery mode. Only the "on" light was lit. The laptop did not "recognize" there was AC attached. The laptop software "health monitor" tells me the battery is good. It seemed to discharge normally when used. In the Device Manager of Windows, the "power-related" items I could find said "working properly." The laptop seems to work fine in battery mode with never an indication that any "power" problem occurred.

 

I then checked the adapter with a multimeter. It was not showing any "DC output." My house power and other devices/electronics all work fine when plugged in.

 

I then ordered a new ac/dc charger (same as orginal that came with the laptop). I plugged it in. The proper "AC" light DID come on this time as amber, meaning it was charging, as I had used the laptop in battery mode. I turned it on. The laptop was working OK. The tray icon for the battery said "plugged in/charging" as normal.

 

However, and this is big, when it was almost done charging, I heard a pop. I looked at the floor where the charger was sitting and a puff of smoke came out of it. I immediately unplugged it. It was hotter than I've felt the previous for sure.

After this, the laptop still seems to work fine in battery mode as described above. Also, the battery did charge that first time to almost full, until the pop/smoke when I unplugged it. So, the battery also did charge and now is discharging at what I guess is the normal rate (I usually don't watch the meter icon. I just use it.), but it seems about right, I figure.

 

Here is the big question. Do you think the laptop is somehow now damaging the ac/dc adapter (crazy!) or do you think I just happened to get a bad replacement adapter.? It seems too coincidental two went down at the same time but one never knows. Any advice/info on checking this problem? I can't find any example of such a potential "unusual" problem when searching the web. Thank you. 

Additional note: After I found out the AC was not working as described above with the original adapter, and I turned it on in battery mode, the battery power was at full. I take that to mean that the original charger did not "die" during use. Otherwise, the laptop would have switched to battery power and used some of that up. Also, and this assumes the "lights" give accurate information, the AC light would have been on (and then turned off) when I turned off the laptop because I always watch that. Also, I don't know the original popped or smoked like the replacement, as I didn't smell anything (or heard when in the room) like with the replacement. When the replacement smoked, I could smell it. My point is, I have no indication (unfortunately) that the original failed the same way as replacement. Weird. Also, I do not know whether to just try another adapter or try to get the laptop serviced based on the information I have provided.


Edited by Bt60SA, 15 July 2014 - 02:23 AM.


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#2 ElfBane

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Posted 15 July 2014 - 04:44 AM

 

I then ordered a new ac/dc charger (same as orginal that came with the laptop).

 

 

Was this new adapter from Toshiba? I'm usually leery of aftermarket parts.

 

Well, as to your question, it's pretty much your choice and how much money you're willing to spend. Repair will cost ~$200-$300 (unless you have a warranty plan). I would try another AC adapter, though. The speed with which the adapter failed indicates to me a defective part.



#3 zingo156

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Posted 15 July 2014 - 07:49 AM

Cheap after market power adapters tend to have problems. I have seen many fail in exactly the way you describe, a pop and then smoke. I always 100% of the time buy genuine replacement power adapters and batteries. I doubt this is anything other than coincidence.


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#4 Bt60SA

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Posted 15 July 2014 - 03:02 PM

Yes, it was a Toshiba brand adapter. Identical part # as the one that came with the laptop. It was the correct one and NOT third-party. I will try another adapter. My concern is, however bizarre, that the laptop is working fine on battery power and all the battery and computer health information (temperature, fan, battery health) are all fine, but somehow, the laptop (whatever internal power components apply) is damaging the chargers. Again, I haven't found any description online where a laptop was known to damage the adapter, perhaps the other way around, but not that direction. I don't even know if that is possible. I search and find nothing for that situation. The problems are all the basics you hear about batteries and adapters, or the ac port in the laptop. While saying that, I will say the to the eye, my laptop ac power port that accepts the barrel end for DC is fine. Also, no physical damage has ever been done to any of the parts.

 

Again, the original charger was not heard/smelled to pop or burn (details in previous post). I actually smelled the original extremely closely. No "burnt" smell. When I smelled the one that popped and released a puff of smoke, I could smell the residual "burnt" smell. Neither showed external damage.

 

I'm puzzled and had to "bother" all of you because the laptop seems to run normally in every way (using it on battery power). It worked fine on AC power while charging before the poof/pop. Crazy.

 

I posted on the "official" forum for my laptop and the only response (a mod) was that he couldn't be sure (coincidence vs. laptop causing it)  and I might want to have it serviced.

 

 

Thanks again.



#5 zingo156

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Posted 15 July 2014 - 03:09 PM

If you look on the bottom of the laptop, does it say which power adapter amperage it is compatible with? The power adapters if under powered for what the laptop requires will get hot and could cause parts to fail. Most laptops will list compatible power adapters by amperage for example on the bottom you might see: compatible power adapters: 19v @ 3.42a, 4.74a etc.

 

Most higher end Toshiba laptops come with a 90w power adapter. You can figure out total wattage by multiplying the voltage 19 by the amperage of the adapter.

 

It could have just been a fluke bad power adapter. Selling hundreds of adapters, I have had quite a few new ones that were DOA or had shorts.


Edited by zingo156, 15 July 2014 - 03:42 PM.

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#6 Bt60SA

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Posted 16 July 2014 - 12:11 AM

If you look on the bottom of the laptop, does it say which power adapter amperage it is compatible with? The power adapters if under powered for what the laptop requires will get hot and could cause parts to fail. Most laptops will list compatible power adapters by amperage for example on the bottom you might see: compatible power adapters: 19v @ 3.42a, 4.74a etc.

 

Most higher end Toshiba laptops come with a 90w power adapter. You can figure out total wattage by multiplying the voltage 19 by the amperage of the adapter.

 

It could have just been a fluke bad power adapter. Selling hundreds of adapters, I have had quite a few new ones that were DOA or had shorts.

Zingo156, it is funny you say that. I clearly know the part number of the adapter that came in the box with the laptop that I've used since Feb. 2013. It says it twice on the label. That is the part I ordered. It is 75W for the standard 19v Dc output. But here is the kicker, when I looked at the tech specs PDF for my laptop (just last night--had to find it during my recent research), it shows the replacement adapter (the specs list additional parts/etc. you can order) as the 90W version, not the 75W that came with the computer (the part number includes a 35 instead of 34, as mine does)! A relative with a similar laptop by Toshiba (i3) that runs at 65W has that 90W version.

I figured if it came with the laptop and it was working fine, I would order that one. So, I ordered the 75W one. I didn't even think beyond "get a "same" replacement."

After noticing this 90W version listed in the PDF noted above, I looked on the Toshiba website for that part, and it shows the above noted 90W version is compatible with my L855 system. I should look again, but I think I'm right. EDIT: Yes, the 90W version is available and compatible according to the list Toshiba and big name stores provide. That is 90W 4.74amps.

 

Just to be clear, the laptop was bought new at a major retailer in its sealed box. So, the adapter I got was what was packaged with it for sure. On the bottom is says 19v dc, 3.95 amps. I know it is 75w.

Please give your thoughts. Thanks.


Edited by Bt60SA, 16 July 2014 - 12:41 AM.


#7 zingo156

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Posted 16 July 2014 - 07:53 AM

If it came with a 75w power adapter, they must have assumed that is more than enough power for the laptop. I am curious though because i7's use a fair bit of power at 100% load. You didn't mention if you have a dedicated video card (not the standard intel HD which is built into the cpu). If you had a dedicated video card, I would assume it would require more than 75w with both the cpu and video card under a full load. If you give me the entire computer model L855-XXXXX I might be able to tell you more about the power it uses.

 

In my opinion, bigger power supplies are better. Reasons why: they will run cooler because they are not running near or at their maximum output. Having less heat and not running at maximum output means you will likely get a longer life out of the power adapter.

 

Laptop computers only require specific voltages and jack ends, most are now 19v or 19.5v. The amperage does not matter as long as it is enough or more than enough for the computer. The computer will only use what it needs. You could use any Toshiba power adapter as long as it fit in your jack, had the correct voltage and supplied enough amperage for the computer.

 

To simplify a 90w power adapter is better than a 75w which is better than a 65w. The only downside is they are larger and harder to carry around.


Edited by zingo156, 16 July 2014 - 08:14 AM.

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#8 Bt60SA

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Posted 16 July 2014 - 10:30 PM

zingo156:

 

It is just moble Intel HD chip. No graphics card. 3 USB. PC RBG. HDMI. Multi-DVD drive. Nothing extra was being used during the "incident." I was only online, as in many times before. Thanks for the info on power. I think I will order the 90W version that is shown as compatible. I guess we'll see what happens when I plug the new adapter in, in relation to the laptop power/battery/charging system. Yikes.

 

This may be the most annoying problem I've ever dealt with. Either the first charger just "died" (reason unknown--but no "burnt smell or pop sound" noticed) as I've found anecdotal evidence of for other users and the 2nd was just a total dud, or, and it would be bizarre to me, the laptop can somehow affect the charger. I'm going with just a coincidence for now as I can't do anything about it yet. I'll leave it at that for now.

 

Thanks for your help.


Edited by Bt60SA, 16 July 2014 - 10:54 PM.


#9 zingo156

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Posted 17 July 2014 - 07:37 AM

There is only one way that I could see the laptop affecting the charging adapter and that is if your jack (in the laptop) has a short. It can happen since jacks tend to take a beating. My dog frequently trips over my cords which pulls on the jack and the power adapter. Because your new adapter did charge while it worked, I suspect you don't have a short.

 

If this is the case it certainly would cause the power adapter to get hot. However, these power adapters are supposed to go into "protect" mode with shorts. They will stop supplying power and only work after you unplug them from the wall and then plug them back in.

 

My best guess is that you got a dud. A 90w should be more reliable than a lower amperage adapter in most cases.


Edited by zingo156, 17 July 2014 - 07:37 AM.

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