
What I Learned From Fixing my Laptop's Motherboard - llimllib
http://www.spinellis.gr/blog/20110529/
======
noonespecial
I saved a hard drive with some very important stuff on it exactly the same
way. I had ham fisted the power connector in backwards and the sacred smoke
had escaped. Lucky for me, I had an o-scope and was able to trace to a
capacitor that had shorted in the 5 volt path. I wired up a new one and all
was well.

You know that awful sinking feeling you feel when you've just done something
monumentally stupid and embarrassing that you're going to have to fess up to?
It feels twice as good +5 when you rescue yourself from it with your geek
super-powers.

~~~
elliottkember
I know the feeling well. When installing an SSD into my pre-unibody, I screwed
a big screw where only small screws go. Straight through the machine, and into
the keyboard. I was lucky, and everything was okay, but it was a tense few
minutes as I considered what a screw hole might do to a logic board.

~~~
misterbee
Electric screwdriver?

~~~
elliottkember
Manual screwdriver. Idiot human!

------
mcantor
Hmm... I guess I'll be the one who posts the Fauxgeek's Lament on this thread.

Reading stuff like this always makes me feel like a second-rate geek! I've had
my fair share of soldering iron burns (for my senior project in college, I
cracked open an RC car's remote and connected it to a BASIC stamp, which I
controlled via RS-232 and a network socket), but the parts of this article
which the author considers "easy" stuff are still a mystery to me. For
example, " _According to the application note I could use a simple signal
diode, so I just pulled a 1N4148 diode out of my component drawer._ " A simple
what diode? A 1N4- _what_ diode? My _component drawer_? I don't even _have_
a... help! S.O.S.! Man overboard!

I'm sure that I could come to feel more comfortable with stuff like this if I
went out of my way to learn more about it, but the applicable extent of my
electronics hacking day-to-day has been unplugging the rumble packs from my
Xbox360 controller. Most of the things I use on a day-to-day basis are not
devices that I feel comfortable screwing around with!

------
timtadh
Reminds me of when I tried to fix my fried amplifier last Christmas. The amp
was around 20 years old and had mysteriously stopped working in the night.
Being cheap I enlisted an electrical engineering friend and together we
stripped the amp down. However, the problem turned out to be 2 diodes failing
hot. The short fried the micro-controller and associated eeprom thus making
the fix more trouble than it was worth. Still, process of diagnosing the issue
was a great learning experience for me. I almost exclusively work in software
so it is always a pleasure to learn about the electrical engineering side of
things.

~~~
jamesbritt
_I almost exclusively work in software so it is always a pleasure to learn
about the electrical engineering side of things._

So true.

I was poking around inside a small headphone amplifier to see what was causing
a crackling noise (I assumed a loose wire some place) when I tugged a bit too
hard and popped off some otherwise healthy wires. I was crushed.

Then I realized _I have a soldering iron_. I did a crap job (I too am way more
CS than EE) but I reattached the wires and got it working again.

Later I learned that the crackling was coming from the cable being plugged
into the amp, which was basically fine.

------
samsonasu
Good story. Reminds of when I fixed a PlayStation 2 that wouldn't turn on by
replacing a blown diode in its power supply. I wonder how many complex
electronics are out there Sitting in landfills just a single diode away from
working perfectly.

~~~
robryan
Probably most of them, even if you are experienced with electronics, with
today's electronics fixing them is more of a hobby than economically viable.
Something has to be worth a very large amount before it makes more sense for
the regular person to seek out a professional to fix something like this.

------
juiceandjuice
Haha, I did the EXACT same thing on my (original 2006) macbook, 14 months
owning it. My power supply died, so I clipped the cable, hooked it up to a 1A
18V variable power supply, but it wasn't charging fast enough, so I hooked it
up to another that was apparently broke and sent 120V to my laptop (people at
work don't throw broken things away apparently)

Anyways, I had experience soldering SMDs before so I wasn't too worried about
the repair, but there were too many power mosfets and diodes and and a ton of
devices at the same potential. Testing voltages and continuity with my
multimeter was mostly futile (and I used datasheets the entire time). I'm glad
you found the problem.

------
jamesbritt
_When I was young I remember consumer electronics, like tape recorders, coming
with their circuit diagram as part of their documentation._

I bought a Teac 4-track open-reel tape recorder many years ago. Still have it,
as well as the docs. I swear you could build one from scratch with the info
provided.

The option to open stuff up (phones, radios, TVs, tape players, etc.) and make
them do things it was not intended for was magical. Maybe Arduinos allow for
something like that feeling now; seems infeasible for most general consumer
electronics nowadays.

~~~
swishercutter
My electronics instructor still uses his amplifier from the 70's because he
can rebuild it with common parts...nowadays if an amplifier section breaks
chances are that it is a chip which may or may not be available (many
manufacturers keep no backstock of one off chips, therefore there is no way to
get replacements).

One of the things I really took with me from his instruction is a disgust at
the "Death of the TV repairman". People would rather throw something in the
garbage instead of having it fixed...not that it is always their fault. It has
become cheaper to purchase an item than to have it fixed, that combined with
the fact that most manufacturers typically do not release schematics until the
item is out of production (if they do at all) and an increased effort by
manufacturers to not allow anyone other than their techs to work on things
(i.e. special Iphone screws, warranty voiding tape, part numbers removed from
chips).

Remember, just because it is small and complex does not mean it cannot be
fixed. If it was built it can be rebuilt (or unbuilt, see ifixit).

~~~
barrkel
I'm not so sure it's like that. Consumer electronics have gotten more and more
integrated, and the bits that are assembled rather than integrated are
assembled with a higher and higher density. The point is, the time spent
finding faulty components and fixing and / or replacing them (or jerry-rigging
something like the article here), multiplied by the hourly cost of a person
with sufficient training to do that job, at this point usually exceeds the
cost of replacing the complete component.

~~~
swishercutter
He could have found the same SMT diode as he was replacing had he tried...he
rigged it because it was the same part (electrically) just a Through-hole
part.

Just because a device is "dense" or heavily populated does not mean it cannot
be repaired if done properly, if the schematic is provided (and accurate per
revision) and you can still source the part it can be repaired. Even IC's can
be removed it just takes different tools (i.e. solder pot, hot air pen, hot
plate, etc).

I assure you there is no difference between troubleshooting old tech and newer
stuff its just different. An IC is just that an "integrated circuit", meaning
they just took what used to be an entire daughter board and made it on a
silicon chip. I would actually argue that it could be easier in some cases to
find an issue on newer stuff since if a chip is failed you just replace it (if
you can get it, which is the real problem).

It's just like he said in the article use the datasheets if you don't have a
schematic typically they are just using some circuit that someone designed 20
years ago and put in the datasheet as an example.

I understand the labor cost involved in fixing an item but I would argue the
long term cost of replacement/improper disposal (even recycling...have you
seen the little kids with the campfires of circuit boards in india/africa that
are trying to reclaim the valuable metals...that is the cost I am talking
about).

As an electronics tech I can tell you that I have worked on many complex
circuits in the field and in production and I have never had a problem with
the complexity...but I have had many issues with finding "one off" IC's and
schematics.

Things are not always about money...sometimes its best to fix things just to
fix them (and hopefully learn something at the same time).

Also, consumer electronics are built to fail. If they were not the
manufacturers would require some IPC class, nobody wants quality though...they
want cheap.

~~~
chopsueyar
_I assure you there is no difference between troubleshooting old tech and
newer stuff its just different._

Exactly.

------
ljf
top tip: use an ice cube tray to hold all the screws you remove. I remove the
first set, put them together in the first cube hole and continue. then just
reverse the order of cubes when you are putting it back together.

~~~
ezy
I actually draw a small outline on a piece of paper of the components I'm
unscrewing and tape the screws to the correct spots. :-)

~~~
shabble
I've been bitten by that scheme after I'd carefully disassembled my laptop,
putting all the screws on a neatly labelled sheet of paper, only to later
attempt to blow out some dust, and have them scatter across the desk and
floor.

Double-sided tape, or actual compartments, sound like a much better idea.

------
dhughes
Take pictures of each step don't use paper since flat surfaces and screws soon
part company use paper cups instead .

~~~
oasisbob
Another technique that I found handy when replacing a Macbook keyboard
assembly: I used a piece of foam roughly the same size as the notebook, and
stuck the screws in their representative places after they were removed.

That model in particular had many screws that shared the same pitch, but with
different lengths. The thought of piercing something with a 10mm screw in a
hole meant for a 6mm screw was scary. I thought this technique worked well.

~~~
ljf
I use an icecube tray. same idea though.

------
rb2k_
I had a Samsung Laptop that I broke while trying to downgrade the Bios image
without properly downgrading some other controller image first. The only
problem was that the soldered EEPROM had the wrong image and thus the laptop
decided not to start. Samsung wanted to charge 700+ Euros (CPU was soldered to
the motherboard).

I was really confused that the world's biggest electronics concern wasn't able
to replace an EEPROM. Luckily I came across bios-fix.de and paid 65 Euros
including shipping to get the old eeprom soldered out, flashed and soldered
back in.

I wish bigger companies would actually try rather than going down the service
path of least resistence :(

~~~
FlowerPower
Makes them and all their partners in the service industry more money, our
economy is based on use-and-dump not on re-use and re-cycle.

------
swishercutter
Always remember the Maker rule..."If it is broken it is fair game..". Open it
up, do your best, if you don't fix it but you learn something then its time
well spent.

If you are like me you also salvage as many parts from what cannot be (or is
not worth) fixing there is always something else to use the parts on.

------
kylemaxwell
Really handy stuff and a reminder that "this product contains no user-
serviceable components" is rarely true. I also liked the structure of the
post. Isolating the lessons and documenting his work while still discussing
the higher-level implications certainly made it more useful than just a walk-
through of how he fixed the motherboard.

------
nopakos
Some trivia: Diomidis Spinellis is currently the General Secretary of
Information Systems at the Greek Ministry of Finance. [
<http://en.wikipedia.org/wiki/Diomidis_Spinellis> ]

~~~
PanosJee
Having such a position in Greece right now can lead to bad reputation I think
(of course the state of the economy is not his fault) :) Diomidis Spinellis is
an alpha geek and a great scientist. He has written great books such as Code
Reading, Code Quality and he is also a FreeBSD committer.

------
r0s
This is why I will always prefer a desktop PC.

Modular components and hardware standards with many third party manufactures.
Laptops will always hold second computer status for me.

~~~
adrianN
Fixing the motherboard of a desktop PC isn't any easier. Disassembling the
laptop is definitely not the hard part.

~~~
scasware
But replacing the motherboard is cheaper and easier on a desktop PC. You can
even buy a different model given that it supports the same processor.

------
jdietrich
Genuine protip:

Replacing through-hole parts on motherboards is exceptionally difficult.
There's so much copper in a modern multilayer board that it's very difficult
to get enough heat in without cooking something delicate. Even with preheat, a
reflow gun and a powerful iron it can be very hard going.

Replacing broken PSU connectors is one of the most common laptop repairs and
should be an easy job, but has a dismally low success rate.

~~~
swishercutter
If you are replacing the connector and you don't care about reuse I find it is
best to cut off the part then just do cleanup, remove as much as you can to
eliminate the heatsinking. Then its up to tip size, temperature and
flux...even still I can't say I have not lifted a few pads in my day.

------
kabdib
Common sense will get you a long way. I was replacing failed memory chips on a
Vax 11/780 and doing other hardware-level things in pretty much the same way;
the downside of screwing up was a multi-thousand-dollar service call to DEC,
since our machines were not under maintenance contract. Well, and bringing a
machine that twenty people were using down, for days (which would have been
the more expensive piece of the equation).

------
linker3000
Lesson 0 has to be 'have several years electronics repair skills under your
belt' - and that's the kicker for most.

I agree though - a bit of knowledge can be a powerful thing; a 'resistor pack'
for my car (to regulate the 4 speed aircon blower) is 80UKP + labour to
replace when it fails but the most common fault is that the thermal fuse
(approx 0.80UKP to replace) blows when the airflow is reduced by an air filter
that just needs a clean-out.

------
pacemkr
I fixed my t42 motherboard by soldering a tiny wire over a blown fuse.

I was in the process of replacing the failed fan on the CPU heatsink. (Had to
transplant the fan from a smaller heatsink that came from a lesser t42 with a
smaller heatsink that didn't fit... Long story.) Prior to the procedure, I
wanted to carefully see if there was even voltage on the FAN pins. I wasn't
careful enough and thought I shorted the pins. Indeed, when I connected the
working fan, it didn't work. So I figured that a fuse blew somewhere. Did some
searching on the web, found a partial schematic for the board, found the 1mm x
2mm FAN_FUSE (or something) and soldered a wire on top of it. To my surprise
it worked. Still using that t42 when on the go.

This t42 is my Oliver, basically.

------
rcamera
I once had to replace my laptop's motherboard because the gpu part of it fried
due to a malfunction that cause alot of heat. I had to buy another motherboard
at Asus, that was actually pretty cheap, 150 dollars, but I didnt want to pay
another extra 100 dollars for, the technician to change the boards.

Well, I couldn't find the service guide, all the ones I found were diagrams,
but not a guide on how to dismantle the laptoo, so I decided to figure it out
myself. After 4 hours I managed to take the whole motherboard apart and
extract all components, then another hour to install the new one. It was
pretty challenging, but I managed to close the case with all parts in place
and no extra screws lying around.

------
inner_trax
Sometime Ago, I tried to repair a Motherboard form a Dell Laptop.

The best thing that I learned these days was photograph every part of the
disassemble process, and where you put each screws and cables, with this you
can go back in the time and see how to reassemble much more easily

------
Tarks
I love stuff like this because the time it took him to fix it was probably
worth more than the cost of the motherboard BUT the fact that he pulled it off
is what makes him so valuable (and cool ^_^ ) and he learned a lot while doing
it. Simply awesome.

~~~
ignifero
Yes. However, this guy is also the general secretariat of information systems
of the greek government, and oversees the online tax reporting system, which
has been having extended outages in the past months. I 'd rather he fixed that
instead.

~~~
chopsueyar
Perhaps he needed a working laptop first?

How else was he to access his private key?

~~~
DSpinellis
LoL

------
chopsueyar
That is ghetto fabulous (heat-shrink tubing with diode). Nice juxtaposition
with the SMD stuff.

Well, the diode did as it was supposed to, and prevented the reverse-polarity
from damaging anything of vital importance.

Nice write-up.

~~~
kragen
> Well, the diode did as it was supposed to, and prevented the reverse-
> polarity from damaging anything of vital importance.

I don't think so. If the diode were being used to prevent reversed polarity,
it would simply have not conducted. If it were a normally-reverse-biased shunt
across the power supply, then blowing it would have left the laptop
unprotected but otherwise functioning (and it would have had to blow something
else in the process, like a fuse). So I suspect it was intended for something
else.

~~~
DSpinellis
According to the data sheet <http://datasheets.maxim-
ic.com/en/ds/MAX1908-MAX8765A.pdf> "D2 protects the MAX1908/MAX8724/
MAX8765/MAX8765A when the DC power source input is reversed. A signal diode
for D2 is adequate because DCIN only powers the internal circuitry."

~~~
kragen
I guess I was wrong. Thanks!

------
mattberg
Off topic: Anyone else read this title as "What I Learned From Fixing my Mom's
Laptop"? I think I have been doing too much tech support for my mom and her
friends lately.

------
dazzla
And I was proud of not destroying my laptop when I replaced the power socket
on the motherboard.

------
samlittlewood
Addition to lesson 2: Use a camera or video recorder to record each step of
the disassembly.

------
cstrouse
Awesome post. I've always wondered what it would take to fix a mobo these
days.

------
Estragon
This is cool. How does one go about learning these kinds of skills?

~~~
logic
For a self-learner at a casual pace, try starting with something like an
Arduino; it'll abstract away a lot of the more complicated ideas at first, and
give you a ton of positive feedback along the way. It's a great bridge to
hardware for a software guy.

For more formal stuff, see electronics/digital computer fundamentals/etc.
courses at your local community college or university, or see if your local
Maker community (if there is one where you live) can point you at more
targeted local resources.

------
raheemm
After a zombie attack, these are the kinds of geeks who'll help to rebuild
civilization. Seriously!

