XO 1.5 Solder Reflow in Toaster Oven

John Watlington wad at laptop.org
Mon Aug 22 17:49:32 EDT 2011


I hope you did indeed fix the problem.
I would point out, however, that 385F isn't
quite high enough to melt the lead-free solder
used in the XO-1, and those laptops might
fail again soon.

Suggestions for future tries:

Start by baking the board for thirty minutes
at 180F (below the boiling point of water), to
remove any moisture that has been absorbed
into chip packaging or the PCB.   If significant
moisture has been absorbed, putting them directly
into a high temp oven will cause "popcorning".

In a normal reflow oven, the board goes through
1 to 3 minutes at between 300 and 400F, then
1 to 3 minutes at over 425F, with at least thirty
seconds within 5 degrees of 500F.   It spends
around 8 minutes total in the reflow oven.

There are two main concerns: melting the plastic
connector housings, and parts falling off or moving
around on the board.

Best of Luck,
wad

On Aug 22, 2011, at 12:00 AM, Chris Ball wrote:

> Hi,
> 
> On Sun, Aug 21 2011, Anna wrote:
>> And no, this is definitely not for the "typical" user, but hey, on
>> Friday I had two dead XO 1.5's and now on Sunday evening I've got two
>> working units. No idea on the longevity of this fix, but OLPC is all
>> about experimentation, right?
> 
> +1 from me.  Nice job!
> 
> - Chris.
> -- 
> Chris Ball   <cjb at laptop.org>   <http://printf.net/>
> One Laptop Per Child
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