[Problem] Laptop shuts off after a momont. NOT mainboard problem

genlen

New Member
Symptoms:
- Laptop Sony sve171a11m boots as normal to bios screen.. it sometimes advances to windows booting screen(dancing circle) or not. It shuts it self off, as in instant power stoppage.
Proposed solutions:
- Laptop power regulator failure? : No. Mainboard replaced(costed me $180) but same symptoms
- Hard drive(software corruption)? : No. Detached hard to boot: well.. it said no bootable device. and shuts off..
Parts(as i see)
- Mainboard
- Optical Drive
- Hard drive
- Wlan
- Power button/vios assistance button board
- power Input(simply 4 wires goes into mainboard)
- LVHD? Lcd monitor cable
- 3 in a row USB
- A fan
- Trackpad, Keyboard, Keyboard backlight
- Speaker.
I think that's it... What seems to be the problem?
 

Agent Smith

Well-Known Member
Since you replaced the MOBO, the only thing I got is the RAM. I thought at first it was the power brick, but you indicated it was using the battery as well and still you had this problem.
 

johnb35

Administrator
Staff member
Either ram or possible overheating. You could have kept this in the same thread though.
 

genlen

New Member
Sorry for making new post. Im not too much familiar with threads.

It probably not the over heating. Since the fan runs and it happens after only few minutes of use (unless it heats up faster then my stove)

Ill check ram out ifs the problem.

I am making though a conjecture if the lcd inverter may cause such problem. Maybe bad capacitor build up?
Lcd works fine uptill the shutdown. No dead pixel(as much i can distinguish under a black screen) and good back lighting. Lett me know~
 

johnb35

Administrator
Staff member
Its always possible that if something broke when you dropped it, it could be causing power issues.
 

genlen

New Member
@morella Checked it with only battery, without battery(cable) and both. Same symptoms.

The machine uses two rams(4x2) so ive tried all orientation possible. Yet no good outcome. Either both rams are malfunctioning, or some other factor may have caused it.
Im looking for spare ram to salvage... Ill update if new ram fits the cure.

NEW OBSERVATION.
I kmow i shouldnt., But ive touched a copper heat sync vent that leads to the cooling fan. And i could feel some heat. About 40~45 degree c. Not too hot to touch, but hot enough to know its hot. (The fan did not run as ut booted. Yet it was twitching as time progressed, as if it thinks if he should run to cool those heat or not.)

Ill test anyway anywhat possible. Give me any hope if there is any.
 

_Kyle_

Well-Known Member
@morella Checked it with only battery, without battery(cable) and both. Same symptoms.

The machine uses two rams(4x2) so ive tried all orientation possible. Yet no good outcome. Either both rams are malfunctioning, or some other factor may have caused it.
Im looking for spare ram to salvage... Ill update if new ram fits the cure.

NEW OBSERVATION.
I kmow i shouldnt., But ive touched a copper heat sync vent that leads to the cooling fan. And i could feel some heat. About 40~45 degree c. Not too hot to touch, but hot enough to know its hot. (The fan did not run as ut booted. Yet it was twitching as time progressed, as if it thinks if he should run to cool those heat or not.)

Ill test anyway anywhat possible. Give me any hope if there is any.
The fan should run when it boots for a short moment then shut of. It must be overheating.
 

Darren

Moderator
Staff member
The cpu fan on a laptop should be running constantly.
Not true. A lot of newer ones won't kick on until needed.

I've seen stuff like this being the power button broken or stuck. If you're able to and comfortable, start it up and then disconnect the power button if it's connected via a ribbon cable and see if it stays on.

Reread this thread. You mentioned the fan twitching. Does it spin freely if you push it?. Does it kinda "wiggle" as it comes to a stop or does it just slow to a stop (when it's off and pushed manually). You'll know what I mean when you spin it.

Some laptops truly do not spin the fan until needed, some newer HP's don't even have fans. Usually they do spin up at boot at the very least but wouldn't rule it out not spinning up until needed.

Very unlikely it's the LCD. Disconnect it and run through external video, stay on? Shorting keyboard also could be a similar issue.

I repair laptops daily, just throwing out what I would try at this point.
 

genlen

New Member
It was the cooling system. Final verdict....? Maybe. A suspection arose.

The new(used) bought fan had faulty wiring on the fan conecctor. Im sending it back.
So old(that i falsely presumed that it was faulty) mainbard supplied cinstant voltage to the fans. However it seems not sufficient enough to cool the board. (?)
It shuts down with same symptoms. So i went OVERKILL and used full sized fan on a naked board. IT WORKED! But i cant use it like that....

Since we know the heat dissipation is the verdict, i am wandering if two heating chipset could falsely shutting itself off even with managerble heat? I didnt think the heat wasnt high enough to have it shut down. Is there a way to higher a heat threshhold? Or is that even plausible?

Before this ludicrous, it shuts down after couple hours of hard 3d graphic gaming with accidental vent blockage. Just for a background information.

Btw. The commmunity here is awesome. More then i expected! Thanks !
 

johnb35

Administrator
Staff member
If the thermal paste is old and hard then it needs to be replaced and you just can't switch motherboards without replacing the thermal paste.
 

genlen

New Member
Welll. It maybe was a false sign. It still shuts itself down.
I cant think of any other possible cause....help me ..T^T
 
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