HomeLet’s say your laptop does not start at all. You plug in the power adapter and press on the power button, but the laptop will not react. It’s dead and the power or battery charge LED will not light up.
What could be wrong? Is it bad power jack or the motherboard is dead?
By the way, the power jack aka DC-IN jack is the power socket on the side or back of your laptop where you plug the AC/DC power adapter.
I’ll explain how to perform basic troubleshooting and find out what is wrong. This is only for experienced people, who know how to disassemble laptops.
First of all, test the AC/DC power adapter with a multimeter. It’s very likely that there is noting wrong with the laptop and your problem is related to the power adapter.
If the adapter tests fine and output correct voltage, disassemble the laptop and remove the top cover.
As you see on the first picture, in my laptop the power adapter plugs into the DC-IN power jack which is connected to the motherboard via a harness.
In some models the DC-IN power jack is soldered directly to the motherboard.
Plug in the power adapter and measure voltage at the point where the DC-IN jack or DC harness (like in my case) connected to the motherboard.
If you are reading the same voltage as on the AC adapter, it means the power jack or harness works properly and the problem is related to the motherboard.
If there is no voltage, most likely there is a problem with the jack or hardness and it has to be replaced.
By the way, in some case the problem could be related to the fuse which is usually located somewhere very close to the power jack/harness connector. You can test the fuse with a multimeter.
If the fuse is bad, the motherboard will appear to be dead even if there is nothing wrong with the power jack and AC/DC adapter. If that’s the case, replacing the bad fuse should fix the problem.
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March 10th, 2010 at 2:48 pm
i have an acer tm 5520. with pomona motherboard. my battery was broken and laptop cudnt power on. i checked few things, assembled it back, and it was running again ( without battery ) i poured some glue on the power jack to fix it in the casing because it got loose. next morning i tried to fit in battery, but it didnt power on. and when i hooked it with adapter without battery it was dead. no l.e.d no power. its been dead since. i had it checked in the market but they cannot figure out the problem. when i check for ac voltage with a multimetre, it seems to get same volts on the ac jack as from adapter, but when i go further, multimetre detecs low volts.
i have another laptop same model. unlike above, it shows same voltage from adapter to ac jack and to battery terminal.
does anybody have any clue whats wrong with my computer? can u suggest me anything? thanks
March 3rd, 2010 at 10:02 pm
vince,
Here’s service manual for Acer Aspire 4720G, 4720Z, 4720 and 4320 series.
Now you know how to get to the power jack.
Good luck!
March 3rd, 2010 at 2:42 pm
I have a Acer Aspier 4720Z. The problem I have is the compter wil not charge the battery or work when plugged in (if the battery is removed). I think it’s the DC board and input, the ac adapter is ok. I could easy replace the board but I don’t know how to get to it.
February 14th, 2010 at 12:12 pm
Hi
I have an Acer Aspire 6920G which has an unusal fault. It will not power up buy has a faint ticking sound. I stripped the motherboard bare & still the ticking sound persists. I have removed various caps, coils, resistors etc but still cannot work out where the sound is coming from! Is there an easier way to try pinpoint the source of this fault? I have tried listening all over the board by ear but the ticking sound seems to be the same – neither louder or softer. Are there components on a motherboard that would be more prone to tick when they have failed?
There are a few caps that are shorting in circuit. I removed & tested all of these and they are good but there still is a short. Strangely though this short does not affect the power supply to the motherboard ie. by turning power supply off or indicating there is a short (flahing led).
This is actually the 2nd motherboard I have come across with the same fault & still cannot solve this problem.
Any advice will be greatly appreciated!
Thanks in advance..
February 11th, 2010 at 10:52 am
BM,
Is it normal? I believe it has to be on all the time when connected to the wall outlet, isn’t it?
Before replacing the motherboard, I would suggest testing the laptop with another AC adapter. Maybe the adapter is bad.
Did the laptop work on the battery power before?
It’s not likely but possible that you have a damaged DC jack inside the laptop. Maybe it shorts something when the AC adapter is plugged.
You can remove the cover and take a closer look at the jack. Maybe the jack has to be resoldered. Just a guess.
The best way to find a new motherboard is searching on the internet by the part number. Usually in Dell laptops you can find the motherboard number on a sticker glued to the memory slot. There is a long string of number on the sticker separated by dashes and one part of number will look like CN-0MD666. This is the motherboard part number and you can google it or search on eBay. The number could be different for your motherboard.
It’s not necessary to buy a new motherboard directly from Dell but buy it from a reputable seller.
February 11th, 2010 at 6:46 am
Hi! I have a dell inspiron 6400. My laptop doesn’t start. The adaptor light blinks when I connect it to the power supply, but as soon as I plug the jack into the laptop socket, the light on the adaptor goes off. And my laptop doesn’t start. The battery gage shows that it is charged. I have tried removing the battery and running only on AC power, but it shows the same symptons. I have tried removing every component and powering the motherboard directly, but with the same results. I am assuming that the motherboard is faulty; where can I directly purchase a new one; can i purchase a particular model of motherboard directly, or will i have to deal directly with Dell? If a particular component soldered on the motherboard (like power jack) is faulty, is it possible to remove it, purchase a new one and solder it back? Thanks a lot.
February 9th, 2010 at 4:02 pm
lee hennessey,
Sounds like software related problem. Could be corrupted registry.
Can you boot in Safe Mode? Try using Last Known Good Configuration too. You can access both if you press F8 as soon as Dell logo appears on the screen.
If nothing helps, you’ll have to reinstall Windows from scratch.
February 9th, 2010 at 2:02 pm
hi there my laptop is a dell latitude d600 it starts up and gets to windows xp loading bit then goes back to the start does it all the time can you help
January 23rd, 2010 at 7:23 am
My Dell Inspiron 600m will intermittently not power on. Does not seem to matter whether the laptop is running on battery or AC. The LED indicates a charging battery when plugged into the wall. I push the power button, nothing happens. Push it again over and over, eventually it will power on. Runs normal when powered on, and if I do a soft restart, it shuts down and powers up normally. But if I shut down completely, the next time I hit the power button I have to hit it over and over until one time it works.
So, could it be the AC, motherboard, power board, or something else? How do I diagnose the problem?
January 5th, 2010 at 10:28 am
Tenzin,
I think your problem could be related to the memory (RAM) failure.
You have two RAM modules installed, correct? Try removing them one by one. Try starting the laptop with only one RAM module installed.
If it starts fine with one module but not with another, the second one is bad.
January 4th, 2010 at 8:24 pm
I have a acer aspire 5630 for while, but now its not working properly, when I tried to start it, the fan runs only for 5 to 10 seconds and after that there is only power led on but nothing else is going on, i can’t hear hard disk sound etc, any suggestion??? I think its fan problem but am not sure about this, you help will be very appreciated, thanks a lot
November 27th, 2009 at 11:21 pm
Malik TOKA,
Sounds like you have a failed motherboard. Sorry, I cannot help you to fix it. I don’t work on the component level. If the motherboard fails, I replace the whole motherboard.
November 27th, 2009 at 10:22 pm
ladoks,
Processor failures are not common. I’ve replaced hundreds of failed motherboards and only very few failed processors.
If you have to choose between the motherboard and processor, go with the motherboard.