What makes a GPU reflow last longuer ?

[Pedro90]

Hi am new to this board and am practicing hot air station refliw on some laptop gpus .

How i can improve reflow life time ?

[Sametbey]

Re: What makes a GPU reflow last longuer ?

you can disassemble and install SMD chip with a similar hot air station. but you should not interfere with the chips in the BGA foot structure, such as the GPU. good works

[Pedro90]

Re: What makes a GPU reflow last longuer ?

you can disassemble and install SMD chip with a similar hot air station. but you should not interfere with the chips in the BGA foot structure, such as the GPU. good works

Hi and thanks for your quick replay .

So do you mean i should not heat the gpu die and only the sides?

[ktmmotocross]

Re: What makes a GPU reflow last longuer ?

reflow is NOT repair. it will last as it can, but havy gaming and u have it back within week

if u want to reflow u MUST have preheater. 70% of heating power must comes from preheater



if u wanna practice, than practice with reball. dont waste your time on reflow

[piernov]

Re: What makes a GPU reflow last longuer ?

https://www.badcaps.net/forum/showpo...02&postcount=2

2.1. Never reflow large BGA
It won't fix the problem since 99% of the time it's not an contact issue between the BGA and the logic board. There's a high risk of damage the board even further.
If you want to confirm if an AMD/NVidia chip is bad, you can heat it up to 200°C max for a minute and a half, no flux. It'll come back to life for a short while and then die again, because it's bad. In this case it has to be replaced.

[Pedro90]

Re: What makes a GPU reflow last longuer ?

reflow is NOT repair. it will last as it can, but havy gaming and u have it back within week

if u want to reflow u MUST have preheater. 70% of heating power must comes from preheater



if u wanna practice, than practice with reball. dont waste your time on reflow

Ok thanks mate . What would be an affordable beginner bga reball station or something i can build up.

[Spider1211]

Re: What makes a GPU reflow last longuer ?

Most "beginner" bga reball station, while cheaper, they usually have rather poor calibration and require some experience to gauge when the chip has reached reflow temperature. Otherwise it is very easy to damage the chip, or worst, damage the board itself due to the latter delaminating, etc.

If you are new to soldering, i'ld suggest you start by practicing through hole soldering using a 'normal' iron with a proper tip and SMD soldering (you can get by with a cheap Chinese one, they are OK for small jobs).

[Pedro90]

Re: What makes a GPU reflow last longuer ?

Ok better send those bga chips for professional reball.

[RethoricalCheese]

Re: What makes a GPU reflow last longuer ?

You would only need to reball if you are replacing a bad chip with a working used chip. Reballing a bad chip has no point.

[Spider1211]

Re: What makes a GPU reflow last longuer ?

Reballing a bad chip has no point.

Unless if you want to practice reballing. Since the chip is already dead, you dont have to worry about killing it and/or ripping pads when pulling stencil out

[coltron]

Re: What makes a GPU reflow last longuer ?

How can you confirm a good reball if the chip is already shot?

[Dan81]

Re: What makes a GPU reflow last longuer ?

I still wonder about it - why do some reflows (with flux, that is.) last a lot of time, and some die within weeks?

Let me show you two cases - one that lasted about two weeks, the other still works for 2 years already:

1. Packard Bell MB65 - G86-703-A2 - reflowed countless times because every time it would die after 2 weeks.
2. HP Pavilion dv6723 - G86-730-A2 - reflowed just twice - first time it worked for 6 months, and died with a white screen, opened up, reflowed it again and it's been working since 2018, and in early to mid 2000s games (which did seem to take a toll, especially since all were maxed out on a 1680x1050 panel I installed from an ASUS G1 - the game it originally died on was Ford Racing 2.)

Maybe proper cooling is a key in having those last longer? The heatsinks on the MB65 were really gutless compared to the dv6700. Just my 2 cents, and of course I can be horribly wrong about this.

[piernov]

Re: What makes a GPU reflow last longuer ?

Both these GPU are affected by NVidia bumpgate. Heating them at 200°C will soften the underfill and the bumps between the die and the substrate, so that they make contact again, but repeated heat cycles will damage them again. On top of that the die has hot spots, it doesn't heat up uniformly creating even more stress. So yes, keeping them very cool will help as they will suffer much less stress from thermal expansion of the die.
The fixed revisions with "good" underfill and bump materials won't fail that way.