[clug] really cheap linux laptop

[Scott Ferguson]

On Mon, 28 Feb 2011 18:23:34 +1100 Mike Carden wrote:
> 
>> > I'm one of those guys who is terrified of soldering irons and I want no part
>> > of the fix described above so what I need is some kind of replacement
>> > machine.
> I read the above and rolled up my sleeves thinking that I'd pipe up
> and volunteer to do it for you. After all, I have had many years of
> experience with surface mount rework.
> 
> Then I read the forum post and saw what is being suggested. Eeep! No way.
> 
> Still, if the T42 is going in the bin, I'll have a go at a slightly
> less random way of reflowing the GPU. I may well kill it, but if it's
> a goner anyway...
> 
> -- MC



Having done a number of similar repairs without error I should at least
point out that the linked article just makes things much more difficult
than they have to be. On a job some years ago I went through the "dead
parts" in the store - of the written off NICs, Video cards, and MBs over
half where recovered by simply baking for 5 minutes at 110C in an oven
(use good ventilation). Chip creep/dry solder is the most common cause
of "failure".

There's a couple of things missing from the linked instructions that'd
make me wary of following them...

First - use some heavy aluminium foil - oven drip/roasting trays work well.

Second - use some thin paper to make your template first. If the hole
doesn't fit flush temperatures will vary across the component.

Third - make a proper sliding frame - two stacks of books and some
plywood with a hole cut in it. Bags of rice and gaffa make great
temporary mounts for the hair-dryer (use lowest hot setting).

Fourth - make sure the owner has truly left the house before you start
using her hair-dryer. Trust me, no matter what great excuse you've got -
your exclusive rights to your razors *are* shot.

Fifth - sod the infra-red thermometer (don't need a theodolite to run a
straight fence either) - slide the lappy out of your professional rig
and put a 20c coin in the exact place where the re-flow component sits.
Time how long it takes solder to melt on it (one cat and dog...) Tip:
bluetack and sticknotes are great markers for the kitchen table.

Lastly - put lappy back in place, use the eraser end of a pencil to push
the edges of your (heavy) foil template down around the GPU.

It's a lot less risky than you'd think. Un-powered silicon is pretty
tolerant of heat. I recently left a late model high-end video card
(accidentally) in the toaster oven for ten minutes to discover it's a
neat way to de-solder a component, *and* that after experimentally
re-soldering it did work again!

If you should stuff it up - remove the GPU completely, and the
screen/lid. You'll then have a nice low power headless boxen and a bonus
screen for your projector project.

For a replacement laptop - an ASUS Eeee PC 701SD (bonus webcam) can be
picked up for under $200, they usually don't have flaky keyboards, it
should have the grunt to do the job, and it's cheap enough to knock around.

Lastly - I'd suggest you don't get rid of your T series, decent
keyboards on lappies are few and far between.

Cheers