Quote:
Originally Posted by laptoppartes  thx a lot for your help.
my question is now why does heating chip temporarily fixes the problem, if the solder isnt liquified with the heat gun, why does work? and i also have another question and is if the cracked solder balls are between the silicon chip and the substrate( not between the substrate and the motherboard) why does everybody focus on the motherboard-chip area?
and one last question...why does the wireless card stops working before the video goes out?
thx a lot for your time and responses |
solder carcks doesn't mean a gap of miles...it means micron level gaps... when you heat the whole chip, thermal dilatation of the balls occurs so these micron gaps are temporary gone away... and the connection is almost restabilished due to the termal dilatation of the heated balls.
but, successives thermal cycles of the chip during the working create various dilatations of the solder balls. the balls increase it size, and decrease it size day after day, hour after hour.... but the crack is there, so when the gap become newly too big... game over... no working motherboard.
the cracks are not alaways between the chip and the substrate, there are no simple method to figure where is the crack, only a scanning acoustic microscope can tell the true, but we all human mortal can't even touch those kind of diagnostic machine...
so we can only think that the crack is between the chip and the motherboard and do reballing...
this is the reason why it is advisable to use new chip.
or, if we have various similar fault whe can have a statistical approac... trying to reball the faulty chip and look if the work last
response to the last question :
the wireless card stops working when the faulty chip is the northbridge, not the video card. for example on hp dv series with amd processors.
when the northbridge is going out, the first sign is the lack of the wifi functionality or other types of faults not correlated with the video section.
when the northbridge is totally out , black screen occurs, but not due to the video chip, but only due to the northbridge chip, that controls the video chips too.