A31p motherboard reflow

[manmanmanman]

Just interested if anyone with a dead A31p motherboard tried to reflow it (since it seems that more often than not the GPU is at fault).

Im unfortunately the owner of 3 A31p's, all with the same motherboard issue.

[kfzhu1229]

I've reflowed a t42 motherboard for the same gpu problem (in fact, similar chip to the A31) with toaster oven and a A30 motherboard also with the same problem with heat gun.
I would go for toaster oven because its so much easier to control the temps. The heat gun doesn't require you to strip everything off the motherboard like plastic insulation stickers.
The T42 lived and the A30 died

[manmanmanman]

I've reflowed a t42 motherboard for the same gpu problem (in fact, similar chip to the A31) with toaster oven and a A30 motherboard also with the same problem with heat gun.
I would go for toaster oven because its so much easier to control the temps. The heat gun doesn't require you to strip everything off the motherboard like plastic insulation stickers.
The T42 lived and the A30 died

Mind me asking what temperature you used?

[kfzhu1229]

I've reflowed a t42 motherboard for the same gpu problem (in fact, similar chip to the A31) with toaster oven and a A30 motherboard also with the same problem with heat gun.
I would go for toaster oven because its so much easier to control the temps. The heat gun doesn't require you to strip everything off the motherboard like plastic insulation stickers.
The T42 lived and the A30 died

Mind me asking what temperature you used?

I use 385F for the likes of these older ones with lead solder, and 370F for the newer ones like T4x and later which uses lead free solder.
Put it in oven for like 8-10 minutes after preheat, then slowly open the door every 5 minutes or so until the door opens fully, then leave it as is for another half an hour.
Remove all the black plastic films before this and tapes too.
Good luck.

[theterminator93]

I tried with a heat gun on an A31p which was intermittently having issues, and ended up killing it completely. Clearly not my field of expertise!

[kfzhu1229]

I tried with a heat gun on an A31p which was intermittently having issues, and ended up killing it completely. Clearly not my field of expertise!

Well this is really why I ended up using oven methods as that is much easier for newbies to control.

[RealBlackStuff]

I use 385F for the likes of these older ones with lead solder, and 370F for the newer ones like T4x and later which uses lead free solder.

Actually the "old" solder with lead needs a lot less less heat than lead-free solder!
So I don't quite follow your logic.
Those figures should be the other way around, and rather with more different temperatures!
Like ~360F for lead solder and ~420F for lead-free solder.

[manmanmanman]

I'll try and get my hands on some sort of toaster or throwaway oven and update the thread once I try it, thanks!

[kfzhu1229]

Actually the "old" solder with lead needs a lot less less heat than lead-free solder!
So I don't quite follow your logic.
Those figures should be the other way around, and rather with more different temperatures!
Like ~360F for lead solder and ~420F for lead-free solder.

Oops alright then. I just followed from some YouTubers that were just casually doing it and they don't quite know the exact temperatures either.
But I do know that 385F worked for both the T42 GPU and the Latitude CPx RAM slot.
If the lead free solder has a higher melting point why does it have more problems with thermal cycling and cracking? Or was it just flawed lead free soldering techniques back then?

[RealBlackStuff]

In the T4x days they didn't know (yet, if ever) what they were doing.
The 'working' temperatures in those early RoHS days were not high enough for the new lead-free solder to properly melt and thus, properly attach.
It probably looked OK, but was anything but!