X31 motherboard cold/broken solder

[daweitowalk]

Hi guys,

My laptop probably has a cold solder somewhere on the motherboard. When I try to turn it on under normal termperature, only the power led, battery led and the fan are noticably on with the rest as dead as a wood. The only way to start it was to heat it up to a high temperature. After that, it ran as well as normal under a normal temperature, which is much lower than the temperature needed to boot it up. It is likely that the cracked joint returns to be unconnected as the computer starts running.

Therefore, I suspect that the cracked joint is only needed to boot the laptop up which might help locate where the cold/broken solder is. If my theory is correct, that will reduce the part/parts for reflowing the cold solder to some specific area/areas, hence reducing the risk of burning the motherboard by heating the whole thing up.

Unfortunately, at the moment, as the problem gets worse, the crack widens to a point that even heating it above the stove would not help boot the laptop anymore. It is officialy dead.

Does anyone have any idea of where the cold solder might be based on the symptoms I have described?


Any advice will be much appreciated!

Cheers,

[kunfuchopsticks]

From my expereince in other non notebook areas I can tell you check areas that correspond to following:

Pressure areas from motherboard screws or other objects.


Don't think it would be near CPU or bridges because they heat up already.

[daweitowalk]

kunfuchopsticks

Thanks for your reply.

Don't think it would be near CPU or bridges because they heat up already.

You probably are right since the cpu running temperature woundn't be enough to rejoin the joint anyway if it is really running. However, why would you think the cpu is running at all? Cannot the power led, battery led and fan be turned on independently of cpu?

[Nick Y]

I would take covers off and try and press gently the motherboard components in order to locate the bad joint. I suggest starting from 'cold' as you should press somewhere and it will start firing up.

[daweitowalk]

Nick Y

Thanks for your advice. I will try that.

However, I think using this method, I can probably have much less than 50% chance of locating the cold joint. This is because of the possibility that the cold joint could be on the bottom side of the motherboard, and doing pressing on the upside woundn't help reflow. Even on the upside, not every bit of the board can be easily reached.

But like I said, less than 50% is still a chance. I'll let you know the result.

Cheers,