rph's DIY FPGA Miner: Skillet-Reflowed?

[poo]

Hi there,

I have a question regarding the thread and instructions found here: https://bitcointalk.org/index.php?topic=44891.0

I'm wondering: what is the process of skillet-reflowing used for?  What does "reflowing" do for the FPGA chips, and how do you accomplish it with a skillet?  Are you only heating up and then cooling the chip, or is there some kind of magic soldering that occurs once the ideal temperature is reached?

Thanks!

[1715373589]

1715373589

[1715373589]

1715373589

[Chomp]

Reflow soldering is the most efficient way to solder commonly used in manufacture. Since the whole board is being evenly heated soldering can be done to multiple connections at a time giving you a professional clean even job vs hand soldering each point. Methods can be done with ovens or hot air. Skrillet is just another method. Solder paste is use to apply exact amount for each connection.

http://www.youtube.com/watch?v=_5lksMvmqQc

http://www.youtube.com/watch?v=gu0v8lfLcKg

[poo]

Oh nice, thanks!

So unlike a CPU which can be slotted into a motherboard, you need to solder FPGA chips onto controller boards?  Or is it more a matter of once the chip is slotted, you need to re-wire the board to maximize SHA2 efficiency for mining?

[kjj]

They do make ZIF sockets for BGAs, but they are obscenely expensive except for very popular shapes.  When Intel ships a couple million 1156 sockets, those are only like $20 each, but the world market for CSG484 is probably only a few thousand units, so those sockets can be hundreds of dollars each.