Nvidia GPU chip problem

[beling]

hi all

So Please could you give me a good cooling solution to prevent video chipset failure after Reballing ?

thanks in advance

[Halim_xu]

Originally Posted by Angello

Hi,

yuo have removed in the four corner glued who attach bga to motherboard?

Hi Angelo,
Yes, i do removed the red glue attached to the four bga corner,..thanks

[Halim_xu]

Originally Posted by Dan Collins

Halim_xu , you won't have issue with removing BGA if you preheat the underside to 150C before you apply upper heat.

Another note, DO NOT USE copper shims. All that does is increase the heat to the GPU because it has no where to go except back to the GPU.
Most times if shim was used, GPU is cooked.

Also, reducing core voltage has no effect on performance unless you also lower the muliplier. Problem with lowering core voltages is the CT and DC AMD series processors do not have much of a range. Use DM series, then you can drop cores to 1.0 volts at full multiplier with no loss of performance and a 10-15C drop in temps..

Hi, Dan Collins
How long should i preheat the underside to 150c?thanks

[Dan Collins]

You preheat the underside just until it reaches 150C then apply your upper heat to the liquidus temp. Don't apply substained heat to the board or you will damage it. Just a normal reflow cycle.

I just apply silver paste to the CPU and a thermal pad to the GPU. But make sure the CPU isn't overheating. Use a temp monitor utility to determine the temps.

[pentu]

Originally Posted by JamesCH

I own an HP DV9700. I tried the reflow trick at home and it did work for about a few weeks, but then it went right back to the way it was. I contacted a circuit-level repair center in Fl called Precision Division. I sent it off to them and they repaired it using a special machine. That was about 4 months ago - and it's still working.
The only downside to the repair is that the fan was modded to run on high all of the time,but I don't really mind that because the laptop runs much cooler and it's better than having a paperweight. I also chose the option to have a secondary fan install. I didn't even know you could do that but they did. So now my laptop has two fans.
I asked them what exactly was wrong with my unit. They said that they had to "redress the BGA pad and reball with eutectic"... I heard eutectic solder is better. They said that's all they use there. And I asked about the copper shim too. They told me that a copper shim is a bad idea for an Nvidia gpu because the chip has no thermal interface material and the shim can crush the chip. Interesting. Either way, my laptop runs really cool so whatever they did, it works

what i understand by the above statement, they have reballed the old nvidia bga chip itself and soldered back with lead based solder, then you might have problem in future, you should have gone for new nvidia bga ic replacement.

[gatolt]

Hi
Does anybody have experience reflowing MacBook PRO GPU. Laptop will not boot-just fans spins for couple of seconds and then turns of. But if I remove memory laptop gives beep code and it will not turn off until I will not switch it off. I guess POST will not go beyond memory test and will not reach GPU. Just question- will reflow help? It is nVIDIA G84 GPU famous for failure. Any ideas?
Thank you

[Bobo9x]

Having troubles finding someone to repair my G84-600-A2 Nvidia GPU , so I tried it myself with heat-gun , pyrometer (poor man's) workstation . Ended up flattening a couple of balls with the inconsistent heat , any help or direction would be a huge plus ........

[Dan Collins]

OMG, heat gun! Consider that mobo trash now. At least the GPU is now toast.

[Bekim_OB]

Hello, i just found this board and i hope to get some feedback, i am trying desperatly to find a reason for that issue.
I am using since January 2011 Achi SC Pro and before I worked whith Bird IR 6000 but i think in this case it doesn’t matter what machine.
I am reballing since August 2010 and I think meanwhile I have lot of experience.
I don’t have any problems with PS3 and Xbox, when I reball them once, I don’t see them anymore.
But quit different with notebooks, I reballed many G86, GO7600 and so on in Notebooks and more than 50% came back in between 2-4 months. HP, Sony and Fujitsu Siemens almost 80-90 %. I have to say that i didn’t do more than reballing in this cases, i mean bios update and copper shims. I just thought when I reball with leaded balls the other things will be not so critical.


OK, I believe that the problem is soldering GPU back. So please tell me your opinions. You know each time i do something else soldering chip back, I have to wait next weeks and months if it will be good or not. I preheat every board till 150 C ( I am meassuring always at the board with 2 thermocouples on 2 chip sides ) than I went to 195 C for 30-60 seconds. Afterwards I tried with 200-205 on top for 30-60 seconds as well. Each time I let a board slowely cooling down. But as i said there were so many comming back.

Few days ago I found this old motorola profile for leaded solder.



So I should go to 220 C for 20-30 sec. and than quickly back to 140 C !!!!!!!!

I am even doing it like that, at the moment, and everything works but I don’t know for how long. I have read in this board that guys reballed hp (DV6000/9000) notebooks 2 years ago and never had some back. What are thay dooing different ??? Can this high temperature ( 220 C for leaded solder !!) be the reason ??? And why is everything OK with PS3 and Xbox with mormal leaded profile up to 190-195 C. ??

Please, Please feedback

Bekim


About current equipment.


Achi SC Pro
2 Thermocouples on Chip Sides
Leaded 0,6 mm balls
Amtech flux for soldering back and Burnley Flux for reball
Normal Reballing Tool with stencils ( no direct heat)
Hot Air Gun melting the balls
Very qualitative soldering wick for clean

[Dan Collins]

Problem with notebooks is the poor cooling system. This problem is especially seen with AMD CPU's because they tend to run very hot and hotter when they get stressed by constant high temps. Don't assume your reflow was bad. If it was, the laptop would have failed right away. You need to monitor the CPU core temp and make sure it stays between 30-60C. If the CPU won't maintain good temps, replace it. I assume you do a proper job cleaning the heatsink/fan assembly and install good thermal paste and pads.
NEVER use copper shims, they will do more harm than good.

[Bekim_OB]

Hello Dan, thank you for reply.

What termal pad do you use ? and why should copper shim make things worst ? ( i never used it but i wanted to start with it)

You have any tip what soft. is OK monitoring a CPU temp. ?

[Dan Collins]

Copper shims tend to collect heat, which makes them ovens on top of the GPU because the cooling system cannot get the heat out fast enough. Also they will crush the GPU if not installed correctly. How many of us have seen mobo's come in with video problems and there is the copper shim. The real challenge is to get the heat out of the laptop. Not keep it in there. There are many good cooling pads out there. You are looking for the highest thermal conductance possible. As for the temp monitor program, do a google search. There are plenty out there, and I do not like to make any recomendations because my opiniions are speculative. You have to decide for yourself.

[geniusmiki]

Originally Posted by Dan Collins

You preheat the underside just until it reaches 150C then apply your upper heat to the liquidus temp. Don't apply substained heat to the board or you will damage it. Just a normal reflow cycle.

I just apply silver paste to the CPU and a thermal pad to the GPU. But make sure the CPU isn't overheating. Use a temp monitor utility to determine the temps.

150c of preheat? we don't risk to damege something?
i have read of 100-120 C of preheat, never 150C!
is this a good tip?

[Bekim_OB]

OK, i understand, i will get some 1-1.5 mm thick Thermal Pad with 6 w/mk and try it.
But i still would like to hear your opinion abot reflowing reballed chip back, of course with leaded balls.

What peak temp do you use and how long (dwell) ?
Do you cool the board fast with fan, or let it slowely cool down ?

I tryed peaks from 190 C to 210 C, dwells from 30s to 90s and i cooled board fast and slow. They worked every time after it, but i just don´t know what is better that NB lives longer !!!!

Thank You, Bekim

[Bekim_OB]

i dont know why but i can´t see may post from yesterday, and try once more.

i would still like to know your opinion about Peak temp and dwell time for this boards. And do you cool them down with fan, or let them slowely cooling down ?