Acer 5755G power problems

rihiii

Hi.

I have Acer 5755G (for 4 years now) and last year and a half i have a problem, which is getting unbearable now

(looks like ill have to get a new device, but i still want to get this one to work good)

So the problem is with power.

First:

computer wont charge if it is on and i plug n the AC adaptor
it will charge the battery (or even just supply the laptop with power) if:
Computer is off
i plug in the AC in the 220V line
i plug in the adaptor in laptop

only then laptop has the power comping from PSU...

Second:

if i run a program on NVIDIA GPU:

battery charging stops, starts, stops, starts, stops.... for random times and finally stops. the LEDs (power, battery and power button LED) all 3 are flashing. icon in the taskbar shows that the battery is not charging and has no power from AC adaptor, but doesn't drain the battery.

I opened laptop to see maybe some flaw that i could fix and found: this one

the power connector is burned including the wires, so ill change that to ensure that my lap doesn't go up in flames so soon Smiley Very Happy

but that is just the symptom, i want to know what caused this, changing PSUs doesn't change anything. and even changing the connection wont change anything... i want to know maybe there are some passives or chips i could change that are burned down...

i got the schematic somewhere on the Internet and am going through it to see maybe i could find something, but am hoping some of you could point me in the right direction where to look, what to change...

as i'm understanding one or more of the elements on MOBO cant take the power that flows through them when i need it that is why all the problems, and it hapened after warranty changed my MOBO because it overheated and burned down the GPU. maybe they put in flawed MOBO, bcs after that started these problems but ofcourse warranty was already through so i didn't send it to repair...

hoping to find an answer or just a clue to follow...

RB

Accepted answers

All comments

JackE

Have you tried replacing the battery?

Jack E/NJ

rihiii

i doubt that batterie is broken because when i use it only on batterie, it still works for 2 or 3 hours...

also dont have a spare batterie, but was thinking abut buing one if neaded...

JackE

>>>it still works for 2 or 3 hours>>>

In addition to the electrochemistry going on inside the battery, it also has a built-in control/sensing circuitry that communicates with the rest of the laptop and its power supply. This internal battery circuitry may have failed even though its electrochemical storage capacity seems to be OK. This could result in both undercharging at times and overcharging at times, the latter of which could explain some of the burned wires you found. So storage capacity isn't the only indicator of battery condition. Accordingly, I recommend that you replace the battery to see if the symptoms resolve. Amazon has replacements for less than $25 with free shipping.

Jack E/NJ

rihiii

OK. Than i guess ill try to change the batterie first. Thanks for the tip. Smiley Happy

JackE

Good luck. And please let us know if it works or not. If not, we can try other possibilities. But the battery seems the most likely cause at the moment.

Jack E/NJ

rihiii

tried to operate laptop without batterie, to see if that change anything.

sadly no. after 5 minutes power shuts down and laptop doesnt have any battery to keep it alive, so it just dies...

il try different PSU later today to see if that change anything.

JackE

That symptom may also indicate a CPU overheating problem. Have you tried to clean the inside of accumulated dust bundles. If you don't want to take things apart, you might want to try to vacuum the air intake port and/or blow air thru the air exhaust port to help remove this debris.

Jack E/NJ

rihiii

cleaned everything, changed thermal paste. CPU stays up to 60 degrees if no major work is beeing done. but the thing is even on those temps power disapears. if i play games than yes, CPU and GPU goes up to 90.

JackE

>>>il try different PSU later today to see if that change anything.>>>

Did you try another power supply yet?

Jack E/NJ

rihiii

Yup, tried. no change. same power dissapearence as always.

JackE

OK. I think you should run a power reset as shown in this video.

http://acer.custhelp.com/app/answers/detail/a_id/13677/~/how-do-i-perform-a-power-reset-on-my-notebook%3F

If this test fails, then I think you should re-run the test only with a new battery. If it still fails, as a last resort, I think you should try recover your operating system to factory fresh while saving your data.

Please report back on the results of your first try with a power reset using the old battery.

Jack E/NJ

rihiii

I'm sorry, but ive done power reset i cant even count how many times, i'm a computer engineer, i know first things u need to do when things go wrong, all these things i have tried.

changing the PSU,

cleaning laptop from dust,

changing thermal paste,

reinstalled fresh windows dozens of times now,

checked the PSU on oscilloscope to see if its ok (it is)

installed unlocked BIOS version to change system fan settings to make it cooler (kinda helps)

even tried to run on battery until its dry, but of course that didnt help either because it shouldnt Smiley Very Happy

checked all the caps on MOBO (fine)

only thing that i havent done is trying a new batterie, but after my tests it is most likely its still functional and not causing these symptoms.

now all the dummy things i have done and nothing has changed. i know that there are some microchips on MOBO that looks like have burned down, but not sure, most likely one of them is the cause... maybe APW7138NI PWM Controller, maybe some other, that is why i wanted your adwise, to know what could cause this problem...