DIY reflowing nvidia chips.

Just reflowed a Samsung R70 board which wouldn't boot.

Stripped the board out. Shielded the surrounding stuff with ali foil. Started to heat it with a craft hot air gun (only 300w, bought to puff up ink according to my daughter). Couldn't get my digital temp probe to work above 150C (maybe bust) so I put a piece of solder on the chip where there was only solder resist. Heated it until the bit of solder melted and then for about 10 seconds more to make sure it had penetrated the chip's substrate. Allowed it to cool slowly by moving the gun away a bit at a time. Reassembled and now have a working laptop.

I did manage to drop the damn keyboard and broke the ESC key.

Now I need to make sure the Nvidia drivers underclock it so it doesn't get too hot.

Reply to
dennis
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OMG, daughter?

Reply to
Adrian C

This technique is much quoted and demonstrated on the 'net for 'restoring' connections that have given way on the graphics engine chip in a PS3. A while back, I did a lot of experimenting with it, and every single time, it worked. For about 2 weeks ...

As far as I can work out, it is not actually possible to 'reflow' the existing solder balls by applying direct heat to the chip. The general concensus of what is actually happening with this technique, is that the heat produces uneven expansion between the chip and the board, and this causes microscopic movement across the crack(s) on the failed joint(s). This in turn causes the insulating oxide layer that has formed within the crack from air exposure, to break up enough to get a connection back across the crack - temporarily.

You might get away with it for quite some time, if the chip is not being worked too hard. Underclocking may be an assistance here. With the ones that I experimented with, I kept one running myself as just a media streamer, for six months or more. However, just about all of the ones that came bouncing back, were from "Call of Duty" players. This game works the graphics engine extremely hard, so the chip gets very hot, and it seems to be this which causes the failure in the first place, and then the re-failure after the 'repair' ...

Arfa

Reply to
Arfa Daily

You can't actually fix it by re-balling either. Its an internal design/manufacturing fault within the GPU package that is the root cause of the problem. I would have taken it back under the SOGA but I didn't buy it so I have no cover under the SOGA.

I know that there is less chance it will fail if it doesn't get worked hard, Nvidia also know this as they made the performance lower in their drivers after the fault was found (but they didn't tell anyone).

I have set maximum power saving on the graphics chip and I am hoping it will last longer this time, or if it does fail it may fail in a way that still allows the machine to boot into a headless server. Before the "repair" it was a door stop.

Reply to
dennis

Yes you can...

reball with leaded solder rather than lead free.

Also fix the heat ladder / sink so that it makes proper contact with the device - on many laptops there is a poor contact between the metal and the top of the device.

BGA is not a particularly unusual form factor. Its just that in this application there is more heat than with many devices.

Note that on many laptops with nVidea GPUs, the GPU is used for running the LCD, but not always the external VGA (this is sometimes embedded in the south bridge chipset). Hence with laptops, you can sometimes get normal operation by connecting to an external monitor.

Reply to
John Rumm

The fault is inside the package. Re-balling it doesn't fix the problem, it just fixes the symptoms.

Its the internal heat sink that is the problem, not the external one. You can fit a perfect heat sink to the outside and it still wont be correct.

In this case the thermal bits inside the package not working correctly is the problem.

Not on this one, it wouldn't even boot.

Reply to
dennis

Not sure what gives you that idea.

You mean it takes the symptom of it "not working" and fixes it?

So that is how you explain how all these "internally broken" BGA packages that can be reballed on the outside, and then work perfectly for years after.

ok den whatever you say...

Reply to
John Rumm

It not working correctly is just a symptom of the problem.

Well as I already said nvidia have changed the driver so they aren't stressed as much to start with. Before the new driver I could easily get GPU temps over 120C now they sit at around 60C even though the CPU is only 46C. That is the die temps BTW not the package which is a lot lower due to the heat sink.

Well you *could* check with nvidia and then understand the truth rather than claiming I am wrong. Go and argue with

formatting link
or someone that actually has any belief that you don't just argue to be a PITA.

Reply to
dennis

Interesting semantic angle...

The (non nVidea) article you cite claims problems with two specific GPUs.

You appear to have extended that to all BGA GPUs.

Reply to
John Rumm

Where?

Unlike you I have stated it was an R70, this has an 8400m GPU.

It is you that is claiming all faults can be fixed by re-balling and claiming there are no internal faults on the nvidia chips.

Its not the only GPU that nvidia have screwed up, but there are different reasons for some of them. Indeed some of them fail due to useless heat sinks in particular machines, however not in this case as they fail prematurely even in machines with good heat sinks.

Do you intend to continue with your argument even though you are totally wrong?

Reply to
dennis

A direct translation from the original Esperanto?

Reply to
The Natural Philosopher

Have you considered a trip to your GP to discuss your memory problems?

A day ago Arfa was discussing repairs to the PS3 GPU, effected by hot air reflows. He expressed his doubt that reflowing would effect a long term repair. You then claimed:

"You can't actually fix it by re-balling either."

Which seems an odd claim since in the case of the PS3, this is the standard fix and generally seems to be an effective long term fix.

You also claimed "Its an internal design/manufacturing fault within the GPU package" supporting this with an article discussing a GPU which is not even used in the PS3.

Again this would seem to be your failure to comprehend.

PS3s den?

Sorry your question is a non sequitur.

Reply to
John Rumm

In this thread which has nothing to do with PS3. Are you confused? You sure appear to be.

This thread doesn't talk about PS3s at all, are you confused? Let me remind you that its about a R70 laptop as stated in the original post. This has the 8400M chip as talked about in the article as was previously stated.

Are you sure you aren't confused?

PS3 probably has heat sink problems but this thread isn't about PS3. The fix is to reflow it and make the heat sink better in case you wonder.

I suggest you see your GP. Your argument is still totally wrong and isn't even anything to do with this thread. Please try to remember this as it will make life easier, maybe you can write it down somewhere obvious?

Reply to
dennis

I have little interest in your memory problems, and certainly not enough to draw them to the attention of my GP.

see above.

I recall. However you were replying to comments about PS3 GPUs.

Time for bed den, you need your beauty sleep.

Reply to
John Rumm

No I wasn't. I have even gone to the extent of stating that only some nvidia chips suffer from the problem. I was replying to the comment about reflowing only working for two weeks.

Then you claimed that re-balling always fixed things, which it doesn't, not even on PS3. Since then you have been ducking and diving to avoid other people knowing you were wrong again.

If you don't have anything useful to add, don't reply, it does you no good.

Reply to
dennis

whatever, the evidence is there, but I doubt anyone cares.

Reply to
John Rumm

Other than watching dense squirm, no not really

Reply to
geoff

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