Weird problem after changing the southbridge on a Acer

[ytsoc]

Laptop came in with no working usb ports. After replacing the ic powering one of the ports(was a dead short) we had power but no comunication on the usb ports.

Replaced the southbridge and now the usb ports work.

But now a weird problem has come up: the laptop dies after approx 5 minutes no matter if it's in windows or in bios or whatever it just suddenly shuts down .

Did anyone else encounter this problem? If it helps i'll post exact models later .

[hazardus]

Re: Weird problem after changing the southbridge on a Acer

Maybe it sounds stupid but did you put the RTC battery back?

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

wish it was that simple, yes i put it back and it's good(not drained)

Another thing i failed to mention is that the fan does not work correctly: it stays locked on a certain speed . That speed is different every time the laptop is powered on, as if the cpu temp isn't being read correctly

[xxxvirus1987xxx]

Re: Weird problem after changing the southbridge on a Acer

you can check it by initial check up..touch every components it most run in low temperature..
2nd check every voltages if thier is a problem....?
try to reset bios..

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

It's almost like a protection, i doin't think it's a temp issue as the 5 minutes remain constant. If it was a temp problem, the laptop would shut down sooner when powered on the second time.
I did try flashing a new bios(via programmer), perhaps i should try to flash one from windows too

[hazardus]

Re: Weird problem after changing the southbridge on a Acer

Try to reflow the SB but first try to clean out the flux under the chip.

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

why the southbridge?

I tried another thing: removed bios and the laptop powers on with no image of course.
The laptop still shuts down after exactly 4:53 minutes, it must be some sort of protection

[hazardus]

Re: Weird problem after changing the southbridge on a Acer

Because that's what you changed on the motherboard.
Now if it's shuts down exactly the same time then it should be the BIOS.
Try to downgrade it.

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

maybe i wrote badly: with or without the bios it still shuts down after 5 minutes.

To be honest i'm leaning twards the GPU chip

[hazardus]

Re: Weird problem after changing the southbridge on a Acer

I know you wrote that you tried it without the bios but it will cause the same problem as the "bad" bios even if it's on the mobo or it's not.
Try to flash an older bios and let's see what happens.

[hazardus]

Re: Weird problem after changing the southbridge on a Acer

Is this an Acer Aspire 5741G with HM67 chipset?

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

it's an acer 5742G HM55 southbridge.
I tried several bioses both from the internet and from spare boards.

On another forum someone said he has the same problem but his laptop had water damage

[Th3_uN1Qu3]

Re: Weird problem after changing the southbridge on a Acer

Tried another CPU?

[ytsoc]

Re: Weird problem after changing the southbridge on a Acer

da , nicio schimbare.

yes, no change

[highpulse]

Re: Weird problem after changing the southbridge on a Acer

hm55 ???time to replace it... its a crap chipset unfortunetly ,and watch out were you will buy your new chip. i had this issue on a 5742ZG ..only after replacing it was ok !

[highpulse]

Re: Weird problem after changing the southbridge on a Acer

now i chekedwell,you replaced HM55 ..what temps have you used soldering the chip ? bottom and up heaters?
Lenght of soldering process.
Cleaned well all pads? no merges on pads?
if water damage , was this happening (shutdown) before the replacement chip ? (for what i've understand on your post , it didnt happen )
chek if the mosfets for VCC for this USBS ports are getting hot ,when the computer turned on .

[Th3_uN1Qu3]

Re: Weird problem after changing the southbridge on a Acer

Since you're in Bucharest, if you're not in a hurry, i can borrow you my own 5472G for voltage measurements and the like. Send a PM if you need it.