Toasty XO 1.5

My XO 1.5 units from the OLPC Contributor’s program kinda pooped out.  But I renewed them in the toaster!  Follow me below the jump for pictures and details.  Warning – lots of pictures.  If you would like higher resolution images for something, lemme know.

I’m toasting the toasting of the Toasted XO 1.5: Toasting in the Toaster Oven which made the Toasted XO 1.5 no longer Toast.

Since I did this, I’ve gotten feedback on the devel list regarding specific solder reflow temperatures.  To wit, Richard A. Smith and John Watlington advised that Quanta uses lead free solder with a melting temperature of 419F.  In particular, Wad imparted the following details:

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,

Since I didn’t have that information before I attempted the repair, I can guess at either the following, both of which are pure conjecture on my part:

1. My toaster oven has extremely inaccurate temperature settings.  I don’t have an independent oven thermometer, but this toaster has always “run hot.”  For example, the package of frozen tater tots says to cook at 425 for 18 mins, but if we do that, they burn.  I set it for 375 for 20 mins and they’re quite edible, not to mention yummy and crispy.  Now, frozen tater tots are not exactly the most scientific method of testing oven temperature, but that’s evidence indicating that my toaster oven might be a bit too fast, thus when I set it for 385, it ran a lot hotter than that.

2. The issue wasn’t the solder joints at all and heating up the board expanded the metal, thus closing microfractures.

Or it’s something utterly unexplained that I don’t understand.   It would not surprise me one bit if these XO 1.5 units refused to boot again.  The only question in my mind is when.  I don’t see this as a permanent solution.

Anyway, here’s the process I used.

We’ve got an ABC rated fire extinguisher, so we went ahead and set that next to the toaster.  Safety first and all that.  At least, make sure you can unplug the toaster or be able to flip the breaker in case something goes wrong.  It shouldn’t but, Murphy’s Law…  At the very, very least, have a box or two of baking soda handy.  DO NOT, under any circumstances, EVER put any liquids on a toaster fire.

I do in fact have a “regular” oven but I only use it during holidays.  It’s from the early 1960’s, and is even more wonky than this weird toaster.  I have to prop it closed with a chair.  Nothing says Thanksgiving like me hollering, “Honey, where’s the oven propping chair?” while I’m putting the turkey in.  Absolutely inappropriate for motherboard baking.

If you are indeed crazy enough to do this, do try to bake your circuit boards in a well ventilated room or set up the toaster outside.  There’s no telling what’s offgassing.  In my case, I’m back in the “sleeping porch.”  This house was built in 1913 when they thought that fresh air prevented and/or cured tuberculosis, so houses built in this era have a room in the back with lots of windows where folks would sleep at night, particularly in the summer.  My toaster is next to an open window.

I can’t break this XO 1.5 any more than it is.  It just died one day.  The power light comes on, but nothing else happens.

XO disassembly is covered elsewhere, so I’m not going to repeat those steps here.  When you’re down to the board, remove the RTC battery, the wifi chip, and the MicroSD card.  I circled those in red in the picture below.

After you carefully remove those three things, remove the board from the casing and check the board for anything that might catch fire or melt.  On my board, there was a cushion under the battery, a piece of yellow plastic tape on a USB port, and DO NOT forget the SD card.  I circled the MicroSD card in yellow in the image below.
For the battery cushion, I eased up a little section with a tiny screwdriver, then gently pulled it off with tweezers.  Same with the yellow plastic tape on the USB port.  The important thing is to get off the plastic sticky stuff that would melt and make a mess.

On the other side of the board, and likely at the same time you’re attending to the yellow tape on the USB drive, you’ll see a white bracket for the video camera.  It pops off with a little force, but it shouldn’t break.  See the comparison in the picture if you don’t pop it off and then accidentally bake it.  Yeah, it puffs up like a marshmallow.  The camera can still go back on without the bracket, but that is not ideal, so make sure you take it off.
While you’re examining the underside of the board, look for stickers you can remove.  Both the two little yellow ones and also the white one under the right hand side yellow one can be scraped off.  The long stickers with bar codes are OK to leave alone.  They should do fine in the oven.
At the end of my scraping and removing, here’s what all I took off the board.  The battery cushion and battery, wifi chip, camera, camera bracket, MicroSD card,  yellow tape from a USB port, two little yellow stickers, and one large white sticker.  If your particular board has something else that looks like it might burn, catch fire, melt, or otherwise make a hazard or a mess, take it off.  Just use your common sense.
So now we’re almost ready to go in the oven.  Rummage up some tin foil (aka aluminum foil) and a metal pan that will accomodate the board.  Tear the foil into four approximately 6×6 pieces and crumple into loose balls.  Here’s what they looked like in my hand to give a sense of scale.  Probably a tad bit larger than the circumference of a US quarter. 
When I did this for my two XO 1.5 boards, I baked them at 385F for 8 mins.  But now I’m not so sure – see my consternations at the beginning of this post.  At any rate, that’s what guys online do to reflow HP motherboards and some video cards.  So, preheat the oven to whatever.  While the oven is preheating, go ahead and set the board on the tin foil balls and try to get the board as even as you can.  
Due to the gap for the wifi chip, you’ll have to move the tin foil balls around to ensure the board is supported.
When the toaster is preheated, carefully pop it in.
Yes, I know my toaster is filthy.  I’m a terrible housekeeper and not fit to call myself a true Southern woman.  But maybe it was all the crumbs in the toaster that imbued these XO 1.5 boards with magic. 
Below is another view of my nasty toaster and the baking board.  Try not to leave this unattended while it’s baking, just in case.  Yes, this will give off fumes, so keep small children and pet birds far away.  Not to mention my mother would bring up quite a fuss with this.  My Mom is visiting next month, so don’t tell her I’ve been baking circuit boards in the toaster.  She’s all “organic” now.
As it happens, we got this fancy toaster for $27 at Bed Bath & Beyond several years ago because the handle was broken.  The LCD display messed up a year or so ago, which is annoying, but the toaster still makes decent tater tots.  Anyway…

BEEP BEEP!  8 minutes is up.  Since I read that you should let boards cool off very slowly, I left it in there with the door closed for about 15 minutes, then opened the oven door for about 15 more minutes.
That is in fact a George Foreman grill to the left of the toaster, but don’t even try to put a circuit board in a George Foreman grill.  Anyway, moving on, the pan might still be a bit warm, so use some common sense and grab a potholder to take the pan with the board out of the toaster.
Set it on the counter to cool.  My counter is tile and I can set boiling kettles on it if I’m so inclined, but you might need to go get a trivet.
Let the board get to room temperature, then put the XO 1.5 back together.  We didn’t worry about the stickers or the yellow USB tape or the battery cushion.  If you pay very close attention, you’ll see the glue around the chips has gotten slightly brown.  That’s about the only real difference I could tell.  
And for some mysterious, magical reason, it’s booting now!  Again, since a solder reflow seems unlikely due to the relatively low temperature, maybe the heat sealed microcracks.  I’ve done this on two XO 1.5 units and I’m really kinda perplexed as to how it managed to work.
Due to whatever offgassed from the board, it’s probably a good idea to unplug and thoroughly clean the toaster oven.  If you have some stale bread sitting about, toast some of that after cleaning and then throw the toast away.  The toaster will shortly be food safe.  Or sell it on Craigslist to unsuspecting frat boys.
I do bake excellent pies and my toaster oven will indeed be in shape in short order.

As an addendum, before I’m pelted with with questions, yes the power and USB ports and audio in/out are just fine.