Laptop switching to battery while connected to AC adapter

Laptop switching to battery power while turned on with AC adaptor
Model: Toshiba Satellite A70-TS100E
I was wondering if you could help me in identifying the cause of this problem.
While turned on, the laptop will switch to battery power even if connected with the AC adaptor (sometimes during boot-up, or after a while) until the battery drains out, he then goes to hibernation (the battery light is off). If no battery in the laptop, it will shut down, and the AC light will blink very fast. The battery (li-ion) will only charge up to 10%, where it then jumps right up to 100%, and will discharge from 100% to 90% then jump to 0%, go to hibernation, and fails to complete the process, shutting down. The adaptor makes a small “camera flash charging” sound, stabilizing at 19v. When charging, it repeatedly makes the “charging sound” Faulty AC adaptor? Or Faulty battery? Or Both?

I think you might have a few different problems at the same time.
First problem: the laptop switches to battery power even with connected AC adapter. Most likely you have a faulty power jack. It’s either broken or loose. It’s a known issue with Satellite A70/A75 laptops and you can fix it by replacing/resoldering the power jack or relocating it outside laptop case.
It also could be a problem with the power cord. Find a multimeter and check the AC adapter. See if the power cuts off when you jiggle the power cord. If it does, replace the adapter.
Second problem: the battery will discharge from 100% to 90% and then jump to 0%. It sounds like a bad battery.

53 Responses

  1. Norman (Bunky)

    Thanks in advance for all the help, great wesite! I need to relocate the power jack on my Toshiba M35X. Once the jack is removed from motherboard and cleaned where do I solder the + and – wires to the motherboard. The pix for A75 puter shows a different layout than the M35X. Wanna Be right the first time, Thanks in advance

  2. Laptop Freak

    Toshiba Satellite A75 and M35X have different motherboards but they use the same power jack, so there shouldn’t be much difference in relocating the power jack for these units. You can find the power jack layout in the comment #94. BTW, you purchased this laptop in the USA, you might be eligible for a free repair. Toshiba extended warranty for some M30X, M35X, A70 and A75 laptops for 12 months. Call Toshiba customer service to find out if you are eligible for a free repair or just take the laptop to a local authorized service provider and talk to them.

  3. Solve my the debate I am having with my parents:

    Is it harmful to the laptop for me to simply close the screen if I am not going to be on it for a while. My laptop is sitting at a desk so it won’t be moved at all. It goes into standby after being left closed for a few minuets, that’s ok right? Is any damage being done to the hardware?

  4. Laptop Freak

    I do not see how it might harm your laptop. When your laptop goes into standby mode, it turns off the hard drive disk, turns off the screen and the CPU goes into the lowest power state too. It’s not more harmful then turning it completely off.
    One of my laptops works as a desktop replacement and very often it runs without restarting for days.

  5. I had an ac jack issue with my laptop and had a repair shop resoulder it instead of replace the motherboard. Of course, Visa Extended warranty is trying to not cover the expense by indicating that the only way an AC Jack can become loose is by “Yanking the cord or dropping it.”

    From your experience, are there any other possibilities of how this could happen. I don’t feel as though I “physically abuse” my laptop and seems to be quite difficult to prove:)

    Thanks so much for your help!!

  6. Laptop Freak

    That’s a gray area.

    the only way an AC Jack can become loose is by “Yanking the cord or dropping it.”

    I don’t agree that’s the only way to get a problem with the AC jack. It also might happen if you carry your laptop a lot and have to plug/uplug the power cord very often, I wouldn’t consider that a physical abuse. Laptops have to be tolerant to that.
    I’ve seen a lot of laptops with the power jack problem. Some of them were definitely abused, some of them were in perfect shape and the owners were very careful but still were not able to avoid the problem.
    By the way, this morning one lady gave me a Toshiba Satellite A65 laptop with loose power jack and asked me to write an estimate for her credit card company, she wants to fix the laptop under the extended warranty. We’ll see if it goes through and the credit card company actually pays for the repair.

  7. I am having the same problem with my Winbook C Series. I have already had the jack resoldered and it has happened now again (6 months later)! What are my options now? Is there any way of getting an extended life battery that you can just recharge whenever you’re not using it by plugging it in to some kind of a recharging source and bypass this whole power cord garbage? Oh – and I have definitely not been abusive either to my laptop…just always have to have the power cord plugged in…battery only gives me about 30 minutes when charged.

  8. Laptop Freak

    I guess you’ll have to resolder it again. There is another option. Some people who experience the same problem over and over again find that it’s better to relocate the power jack outside the laptop case.

  9. Prashanth

    While using the internet, does the battery drain faster than the normal usage?

  10. Laptop Freak

    Compare to what, to an idle laptop?
    I would say yes, when you are browsing the internet the battery drains faster. You are loading pages with graphics, so the video card and CPU work more intensively and the battery drains faster.

  11. Scott Fisher

    power jack replacement on HP Pavillion zt1170

    I have a new power jack in hand and ready to tear into my laptop, What soldering tools should I get? I see small 25watt pens & cordless cold soldering tools? what is too hot? and solder type is best?

    I assume relocateing the jack outside is the BEST way to prevent this from happening again? could I use a small chunk of drop cord wire for this? what type of wire and gauge would be best? and are there detailed instruction for the zt1170 or use the HP Service media Library link

    Is it best to use the new jack or is it possible the old jack can just be re-soldered?

    THANKS -Scott

    my old soldering gun is one of those old Colt 45 looking beast which I’m guessing is WAY to hot for what I need, now what (haha) 🙂

  12. Hi. I am having a similar battery problem with my Dell Inspiron 1150. Here’s a typical scenario…

    1)AC adapter is plugged into laptop.
    2)The laptop boots up fine and works normal.
    3)Suddenly, the laptop switches from AC plug power to battery power.
    4)The battery slowly drains and eventually dies 1-2 hours later (depending on charge).

    When the laptop is working normally (working with the AC adapter), I’ve tried jiggling where the AC adapter plugs into the computer. It doesn’t seem to make the computer hop to battery power.

    I can even unplug the AC adapter, allow the computer to switch to battery power, and plug it back in and watch it switch flawlessly back to AC power. But then, randomly, the laptop will switch to battery power and eventually shut down. The only workaround I’ve found is to shut down, unplug and replug the Ac adapter, wait, and restart. Then the laptop works fine for an undetermined amount of time.

    Any ideas? I was thinking either the AC adapter is dying or something with the BIOS. THanks for your time.

  13. Laptop Freak

    Scott Fisher,
    I use a Weller digital soldering station (50W unit, temp range 350 °F – 850 °F) and for soldering/resoldering laptop power jacks I set the temperature to 850F. Works perfectly fine for me. If the old power jack is not broken, you still can use it. Clean the power jack contacts and coat them with a new layer of solder before you put the jack back on the motherboard. Also clean and coat the contacts on the motherboard.

  14. Laptop Freak

    It’s hard to say without testing the laptop with a known good AC adapter. Yes, it could be just a bad AC adapter but it also could be a problem with the system board. I would probably replace the AC adapter first, they are not very expensive.

  15. Scott Fisher

    Freak: Thanks for the info, I decided not to purchase tools and attempt myself, I tore it down and took to my local TV/Appl. Repair Guru, He has made many laptop repairs and said only $15-$20 bucks, WHAT A DEAL! My hats off to you Elec. Repair Geeks and Thanks for the Web Site !! 🙂

  16. I have a Toshiba Satellite P25-S5263 and I need to replace the power jack on it, is there some kind of easy tutorial which shows what to do ? And also what does it mean “to modify the power adapter to the 2.5mm center pin” Will I have to modify this 3.0mm DC power jack(which I’m going to purchase on ebay) for it to work with my laptop?

    I’d really appreciate any help I can get, Thanks =)

  17. Laptop Freak

    You can replace the power jack in three “easy” 😛 steps:
    1. Find a new power jack. You can find it really cheap here, if you search by P25 power jack
    2. Remove the motherboard from the laptop
    3. Replace the jack
    I hope it helps.

  18. I have a Sony Vaio (model PCG-V505DX). The problem is that when I plug in the AC adapter, it powers the laptop intermittently. Windows shows messages that switch between “AC plugged in” and “Running on batteries”, and the messages alternate very fast. I tried adjusting the connector and the wires on the AC adapter but there was no improvement. I checked the output of the AC adapter which shows around 15.6V rather than the 16V indicated on the label. I assume that is probably OK. So does that leave the power jack as the potential problem? I appreciate any feedback on this issue. Thanks.

  19. Hello! I have an hp dv4305. I am having a problem with my power jack. My husband was holding the laptop, and it slid off onto his legs and bumped the ac plug. Now it will only charge if we put pressure on it. I guess I really need to know how to check it. Thanks, Kim

  20. Laptop Freak

    So the “AC plugged in” message appears only for a moment when you plug the power adapter, then it switches to “Running on batteries” and you cannot switch it back to AC if you wiggle the power plug or move the cord, right? Most likely there it’s just a power jack problem and you’ll have to resolder it. But there is a small possibility that something is wrong with the AC adapter.
    I would take a look at the power jack before ordering a new AC adapter.

  21. hello!
    i have a sony laptop here, it boot up goes to window with battery no problem. when using ac and battery to boot into windows , the power icon will switch between ac and battery in a very fast way. if just using the ac laptop only boot up for 2 to 3 second the shut off
    is a vaio pcg-v505ex i alrealy check the ac and power jack it both works fine, tried with deferent mem same problem. any idea what is wrong with it?
    thankz in advance.

  22. Eric,
    See my post #18 and the response #20. I think our laptops have similar problems.
    I have since disassembled my laptop to expose the power jack. I originally measured the output voltage of the adapter to be 15.6V. When I connect the adapter to the power jack, the output voltage from the power jack is around 15.4V, not much difference. Therefore, I think the problem is the adapter since the label says output voltage should be 16V. I’m not sure if my logic is valid but it would be interesting to know what the output voltage of your adapter is.

  23. Ming
    Thankz for the replay, guess your are right. retested the ac it show 15.43v, i got another av from deferent laptop it show 15.6v. when connect the 15.6v ac to the laptop every thing works fine, when connect 15.43v to laptop same thing happen again. 0.2v make that much deferent ??

  24. Eric,
    Good to hear that the adapter solved your problem. That’s interesting because I got a universal adapter and the output voltage is around 16.3V. That solved the problem for me as well. There may also be current differences.
    By the way, it also turns out that I have a bad battery which discharges very quickly.

  25. Hi. I wrote in earlier about my ac jack. We have to plug it in and pull the cord toward us for it to charge. It plugs in on the side. I am hoping from what I have read we can just get a new jack soldered on. But now we are having a new issuse pop up. Every now and then upon restart the computer will beep 3 times. I looked this up and found out something about the first 64 of memory. I did the windows memory diagnostic, but it didn’t show anything wrong. It dosen’t do it all the time, so I wonder if that is why it’s not showing. Thanks, Kim

  26. Hi
    My laptop seems to have the same problem. mines is a HP dv5120us which i got about half a year ago. At first i thought it was a power cord problem and bought a new one but it didn’t work. I tested it with my cousins laptop which is the same model with my battery and powercord and stuff which worked perfectly fine on his computer.
    Is it the port which my power cord goes into or other parts that connect with the battery?
    i move my laptop around alot could that be a cause of my problem?

  27. Laptop Freak

    I think it’s a problem with the power port on the motherboard. You got the laptop about half a year a go so it still should be covered under warranty.
    You move your laptop with the power cord attached, correct? Yes, it could be a cause of the problem because if you accidentally pull the power cord while it’s still attached to the computer, you are stressing the power jack and overtime the jack might lose connection with the motherboard.

  28. Hi there!

    I have kind of that problem with mine Toshiba Satelite M30X. Well quite same, there are differences:

    – computers is running very well when on table (or other stable surface) – nothing happens, everything is just fine

    – when i hold it on knees it’s also working good, but sometimes battery LED is suddenly going off and system is switching to battery. When i unplug and insert again power cord – everything is back to normal. It’s not permament – i still can work hours holding it on knees and everything’s just fine and one moment – *blink* and it’s on battery.

    – i`ve manipulated the jack around socket and didn’t noticed LED flickering or turning off. Shaked whole notebook and still nothing – like problem even doesn’t exist.

    – tested AC – aprox. 19+ V

    Well i think that if it`ll be motherboard/electronics issue, then there should be no matter if laptop is on table or knees – battery should acting weird both times.
    Other hand – if it’ll be real power jack problem it should turn off battery when moving cord right?

    So i don’t understand – could it be some minor problem with power socket? Somthing like not full crack, that maintances power supply for sec. but not such strong to unable normal functionality? How you think? Be glad for any comments on it!

  29. Laptop Freak

    I think it still could be a power jack related problem, it’s very common for Satellite M30X and M35X notebooks. I’ve seen it hundreds times and sometimes the problem is intermittent and it’s very hard to reproduce the problem. Laptop might work for hours and then soddenly switches to the battery power without any reason. Unplugging and plugging back the power adapter “fixes” the laptop for a few more hours.

    I’ve manipulated the jack around socket and didn’t noticed LED flickering or turning off. Shacked whole notebook and still nothing – like problem even doesn’t exist… If it’ll be real power jack problem it should turn off battery when moving cord right?

    In some cases you cannot make it fail just by moving the cord or jiggling the power plug. Most likely the jack is still connected to the motherboard but the solder that keeps the jack in place has a micro-crack and the laptop looses power intermittently (when it warms up for example).
    I would try to resolder the power jack first. If you are going to fix this laptop yourself this disassembly guide ( for Satellite M30X or M35X notebook might be useful for you.

  30. Hi! Thanks for your reply – i`m glad that it`ll could be only minor problem with solder.

    Well i think i`ll try to do it my self, since “pro” company wants a lot of money for it. But have another question 🙂 Should i totally unsolder socket from motherboard and solder it again or i`ll be good to only put new solder on existing one?

    Thank again for your help! I appreciate that!

  31. Laptop Freak


    Should i totally unsolder socket from motherboard and solder it again or I’ll be good to only put new solder on existing one?

    I always unsolder the socket, clean soldering pads on the motherboard and pins on the power socket, apply new coat of solder on pads and pins and then solder the socket back in place. If you just put new solder it will not last for a long time. You’ll need some soldering experience to accomplish this task. If you are not careful enough you can damage soldering pads/traces on the motherboard.

  32. Hello.

    Last June I purchased a Toshiba Equium A60-692. 8 weeks after it arrived I was using it on my lap with it plugged in when I noticed that the power connection was constantly flickering on and off. To my horror smoke started coming out of the back so I switched it off and sent it back. They told me the circuits on the motherboard responsible for the power connection had fryed. They replaced the motherboard and returned it to me. Unfortunately I occasionally experience the flickering again but as it only happens occasionally I don’t think they’d take it back.

    However, I have noticed that my battery’s life is considerably shorter than it once was. It is 6450 mAh battery but only manages 90minutes at a strech. Could this have been caused by the faulty connection (could it kill battery cells?) and so entitle me to a replacement battery?

    Any advice you can give me would be greatly appreciated. I am very impressed with this site! Thanks.

  33. Laptop Freak


    Unfortunately I occasionally experience the flickering again but as it only happens occasionally

    It’s possible you have a power jack connection problem. Even though it’s not failing now, it might fail later.
    Try completely discharging and then charging the battery a few times. 90 minutes sounds normal to me.

  34. I have a problem with my ac adaptor for my sony pcg-fx370. when i plug it in, the computer turns on but it doesn’t charge the battery at all. if i take out the plug, the computer will turn off. i did a bios update but still nothing. how can i fix this problem.

  35. Hi,

    I have a Toshiba P30 Satellite.

    It used to completely switch off at random, and was diagnosed with a known Toshiba manufacturing fault, and the motherboard was replaced.

    However, it is also switching from mains power to battery, and seems to be only doing this when the DVD drive is used, either to burn to, or copy from. Battery lasts about 25 mins on the P30 at the best of times.

    Any suggestions as to the cause, given that a new motherboard was installed, and that fixed the shorting error?

    thanks, hamish

  36. DVSoftware

    Sorry i put my original question in the wrong section. I’m unfamiliar with the site.

    Original question:
    I have a problem with my laptop battery, and i’m not sure whether a battery is faulty or it’s the laptop. Computer itself works fine, but won’t startup on battery. Software says it’s 23% charged and won’t charge anymore, so i suspect the battery is dead. Ok i took the battery out, and out of curiosity, i disassembled it, took a multimeter and measured 14 volts, and that’s designated voltage. How can i identify if it’s just faulty battery?”

  37. Laptop Freak


    Computer itself works fine, but won’t startup on battery. Software says it’s 23% charged and won’t charge anymore, so i suspect the battery is dead.

    Sounds like a bad battery.

  38. Hi guys
    I agree with freak, though the battery says is has enough volts, it might not be pumping enough AMPS to turn on the machine. also have you tryed re-calabrating the battery? since you don’t say what laptop you have, I know most have calabration programs you can download (for their particular machines) and lastly some machines have what is called chargeble hours (or life cycle) and a diode in the battery to basically turn off the damb thing once it reaches that point. way to get you to spend more money LOL

  39. DVSoftware

    Battery won’t charge at all, so I can’t recalibrate it. I also don’t use MS Windows so I can’t use that kind of applications.
    Machine is HP Compaq NX9105, and i also suspect that there is some lifetime counter on the battery but i’m not into electronics so much…

  40. Hi dudes,
    I have a problam with my HP nx9105 from a long time.
    It suddenly stopped working. When I plug in the power supply the power light in the laptop turn on form 3 seconds and then turn off. Even if I press the laptop power button it also turn on for 3 seconds then stopes with no sound at all. I took it to the agent and they said the motherboard needs to be replacem but I don’t agree that I should do so and spend too much.
    Please, help. What’s can I do??

  41. I have a Satellite A55-S3062 w/the same power jack problem. Sometimes it powers via AC, sometimes it does not. The jack is loose. Looks like I can get a new one on ebay, etc. Is it simple enough to open the case and plug in the new one (looks like it is NOT soldered, but just plugged in)? If so, is there a manual I might look at? Thank you!!!



    I have read the commentary that is currently posted and I have a more specific problem that has yet to be discussed.

    I own a Toshiba A75. For no reason, the battery light will go out and the machine will go to battery power. The power light remains on and the a/c light remains on.

    If I turn the machine off, the battery charging light will come back on. SOMETIMES, when I power it back up it remains on, charges the battery and stays on. SOMETIMES, when I power it back up, the light will immediately go right back off. SOMETIMES, if I take the battery out and put it back in, it will remain on for hours and others??? it will go right back off. All the time the other two lights (power light and ac light will remain on).

    Sometimes if I take the power cord out and put it back in, the battery light will flicker but really does nothing.

    My input plug has been re-soldered sometime back in the past. So it is not the “WIGGLE” problem!

    Signed “Frustrated”.

  43. Hi
    I am facing the same problem with my lenovo laptop. Then I switch off the laptop and keep it connected for charging. Once it charged fully problem disappears. But if I worked some time on battory then connected the power the problem comes back again. I think this is some problem with the battory driver which senses incoming power as low when battory gets charged from that and switches the system back to battory.(just an assumption.) To be frank the discussion materials here i found is not addressing the point.

  44. Laptop Freak


    I am facing the same problem with my lenovo laptop. Then I switch off the laptop and keep it connected for charging. Once it charged fully problem disappears. But if I worked some time on battory then connected the power the problem comes back again.

    Find out witch BIOS version is installed on your laptop and then visit Lenovo website and search for the latest BIOS release. If your BIOS is outdated, try updating it to the latest version. It’s not difficult if you follow the instructions. I think updating the BIOS may help.

  45. Ronald

    i like universal ac adapter if it do not go overheat and burn users
    whatever ,it is easy and convenient

  46. may88_98

    Hi, I just had this switching problem today.
    When I used the battery, all was alright. When I charged the battery, the switching came on and off. When I took out the battery and just used AC, everything was ok.
    Is it the problem with my adapter? I lent my laptop to a friend today, and he mentioned that he dropped the adapter (I am not clear how or how high he dropped it).
    My laptop model is Dell Inspiron 6400.
    Thanks so much.

  47. waverley54

    I have a Toshiba P30 auto switching to battery when AC power adapter is plugged in. The battery drains away and system hibernates, despite AC power light staying on. There is no flicker in the AC power light when moving the AC input jack around to indicate a loose connection. When turning-off the system after it has switched across to battery, the power-on button remains illuminated even after shut-down until the AC jack plug is removed and re-inserted. At the point of re-insertion, the battery charge indicator and AC power lights illuminate as normal.

    Surely a fault in the switching mechanism which assume is solid state electronics if that still exists?

    Thoughts would be appreciated as my laptop dies!

  48. Stuart Filler

    When issue is not bad connection, appears is voltage from power supply. When I use hp ps rated at 18.5v or aftermarket rated at 19v, no problem. When use old Compaq ps rated at 18.75 v and 3.15 amps–I had soldered in a second, slightly larger jack from an Armada 4100–I get the cycling from AC to batt. As stated by others, setting maximum brightness eliminates the brightness fluctuation. When it fluctuates, battery continues to run down, maybe slower. I am getting to the opinion that the fluctuation results, as suggested by others, from the ps voltage and/or amps/watts. Either the old 18.75v rated ps is giving less than 18.75 or the amp output is low–sorry, do not have the amp rating for the ones that work. Yes, there can be a bad jack or a good jack but a plug that needs to be squished a bit to snugness; and yes, there is a reset technique involving turning off, removing battery, maybe even removing bios battery, I forget, that works for reset; but as stated, am coming to opinion that new ps is best solution. Stuart

  49. Somange

    i have an Hp Pavillion dv7 and the charger beeps when its plugged when i plugg it to the labtop it doesnt charges but it beeps

  50. I am having issues with our laptop a dell inspiron 1525, my son had spilt a very little amount near the laptop and it ran a little under it. After a day it started working again fine. A few weeks later we now have an issue where to computer screen goes black and if you hit control alt it comes back on,and it also dies after a little bit. We have a power cord connected because we can tell the battery was messed up so we dont have it in at all. We plan on replacing the battery but is there another issue with it?

  51. danny mc

    My laptop battery only charges when the laptop is upside down. I have an MX6447 with a history of charging problems. I replaced the motherboard a year ago. I removed the jack from the motherboard and soldered in a pigtail wire w/ an inline connector on the end to plug into the power supply. It worked great for a couple of months, then it quit charging. I’ve checked connection to motherboard and it is good. When I flip the laptop upside down it starts charging! Any idea why? Is there a way to jumper the motherboard battery connector to bypass the battery?

  52. i have an acer 5720 laptop. i have just purchased a new battery. i keep on getting a message which says battery not comptible. Is it an software issue, if yes kindly let me know the solution.

  53. I have a sony vaio pcg-v5050dx with the ac charger problem mentioned above. It reads as fluctuating in the mid 15s, not 16v as it should the jack seems loose as well. I was quoted $150 to repair the jack. This seems excessive, but I was told it takes approx 2 hours. Is this something a complete non0techie can handle? they guy told me my model does not have the jack soldered to the board, instead sits in a plastic well. Any input is appreciated. thanks!