Is This Typical GPU Failure ?

[mmartell]

Re: Is This Typical GPU Failure ?

Spoke too soon. After a reboot very few artifacts but the cpu/gpu fan running quite a bit faster. Ah hell will try reflow one more time

[Th3_uN1Qu3]

Re: Is This Typical GPU Failure ?

Remember to reapply good quality thermal compound. And don't be afraid to blast the die with really hot air - just don't do the same for the green substrate.

[mmartell]

Re: Is This Typical GPU Failure ?

Remember to reapply good quality thermal compound. And don't be afraid to blast the die with really hot air - just don't do the same for the green substrate.

Ya I hit it at 450f but I only ever use the station at 500f as it is mostly useless below it but I figured after four minutes it would work. I've got no problems hitting it again at 500

I will say I only have generic paste but have never had a problem with it the several times I've used it, lastly on an LG z-sustain. How hot does the vram get ? I've been reusing whatever goop is on there already as I have no thermal pads let alone know what thickness to use.

[Th3_uN1Qu3]

Re: Is This Typical GPU Failure ?

The VRAM does not get hot, there's no problem leaving the old pads on.

Oh, so you were talking deg F. I was talking Celsius. Does it even melt solder at 450F? You will want to use a setting that you would normally use for desoldering small parts.

[mmartell]

Re: Is This Typical GPU Failure ?

If you're NOT talking F you're going to burn your house down. Or I could be confused, wouldn't be the first time

[mmartell]

Re: Is This Typical GPU Failure ?

And btw, I'm guessing there's no solder inside the die so how does heat repair the connections even temporarily ?

[Th3_uN1Qu3]

Re: Is This Typical GPU Failure ?

I am talking Celsius. Really. Remember the hot air station will have its sensor inside, in front of the heater element. By the time the air goes thru the nozzle and into the outside world, it cools down significantly.

If you use a multimeter probe put in front of the nozzle of your hot air gun, it should read around 320C. I can't see how lead-free solder would melt any lower than that anyway. I use 400C for working with leaded solder and 430-450 for lead-free. I don't think my station is poorly calibrated as this is my 2nd one and i'm using the exact same settings. My hot air station is a ZD-939B.

I have however found that for Gordak ones you need to set the temp lower, as the heater seems to be higher power. The Gordak i had at work did not have its heater marked in deg C, just from 1 to 8. I had to use it at the "5" position or slightly lower on sensitive boards otherwise it would burn them.

There is solder inside the die, obviously. How do you think they connect them otherwise? They don't use bond wires anymore for chips this dense.

[reaper57]

Re: Is This Typical GPU Failure ?

And btw, I'm guessing there's no solder inside the die so how does heat repair the connections even temporarily ?

The problem might not be the bga under the chip. The crystal is also connected to the die via solder balls. They are a lot smaller, but still solder.
Also you can take a look at this, it should clarify why heat effects it.
https://books.google.no/books?id=G9A...%20die&f=false
Also if you had your station set at 450F the first time, that would explain why there still are artifacts. The air gets a lot cooler by the time it gets to the chip, and if the problem is the solder under the chip it's even cooler when it reaches it. I wouldn't be surprised if the chip was at under 150C (302F) during the reflow. But this is good! If the chip starts to show signs of life with only a low temp reflow, that means that there is a good chance for it to be fixed by a proper one.

[Th3_uN1Qu3]

Re: Is This Typical GPU Failure ?

The problem might not be the bga under the chip. The crystal is also connected to the die via solder balls. They are a lot smaller, but still solder.

That is exactly what i was talking about. These nvidia chips are known to have a problem there.

[mmartell]

Re: Is This Typical GPU Failure ?

A quick update: all artifacts have disappeared and the display is rock solid. This is without another reflow and also without stress testing. Temperatures as reported by the sensor seem nominal at about 35c. The cpu/gpu fan runs quite a bit faster than it did when the computer was "broke" so I'm still going to disassemble it to make sure I didn't leave a sensor unplugged and also check the heatsink-gpu surfaces.

[Th3_uN1Qu3]

Re: Is This Typical GPU Failure ?

If it ain't broken, then don't fix it. These things do fix themselves sometimes. If it breaks again, hit it harder next time.