Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default reflowing BGA with a hot air gun?

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric
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Default reflowing BGA with a hot air gun?

On 02/08/2018 11:09 AM, wrote:
I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric


Since the machine is on its way out anyway, why not give it a whirl? Do
your backups first, of course.

Laptops use the circuit board as a stressed structural element, so they
sometimes crack when mistreated, e.g. when picked up horizontally by a
front corner. I had one go like that, and the symptoms were similar to
yours. Now when I need to one-hand a laptop I pick it up near the hinge
instead.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

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Default reflowing BGA with a hot air gun?

On Thu, 08 Feb 2018 08:09:32 -0800, wrote:

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric


We all have to start learning somewhere. My domain is
LearnByDestroying.com which should offer a clue as to how I start
learning. If you've never worked on a laptop before, your problem
will not be the hot air reflow, but rather the disassembly and
reassembly. Spare screws, mangled flat ribbon connectors, and broken
plastic are common. I suggest you use a digital camera to record the
disassembly to help with the reassembly. You might be lucky and NOT
need to remove the motherboard from the case, but that's not typical.
Before you blow dry your machine, you might look inside, around the
lower left corner, and see if any connectors have come loose. Also,
find an air compressor and blow out the dust, especially around the
fan.

There are YouTube videos showing how to use a hot air gun to reflow a
BGA.
https://www.youtube.com/results?search_query=hot+air+bga+reflow
Make sure you build a heat shield out of aluminum foil to prevent
melting nearby plastic parts. Practice on scrap PCB's before
attempting to fix the unspecified model Asus laptop. It's quite
difficult to tell if the low temperature solder balls have reflowed.
I'm undecided if liquid flux does anything useful.

Good luck.

--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default reflowing BGA with a hot air gun?

On Thu, 08 Feb 2018 09:17:52 -0800, Jeff Liebermann
wrote:

On Thu, 08 Feb 2018 08:09:32 -0800, wrote:

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric


We all have to start learning somewhere. My domain is
LearnByDestroying.com which should offer a clue as to how I start
learning. If you've never worked on a laptop before, your problem
will not be the hot air reflow, but rather the disassembly and
reassembly. Spare screws, mangled flat ribbon connectors, and broken
plastic are common. I suggest you use a digital camera to record the
disassembly to help with the reassembly. You might be lucky and NOT
need to remove the motherboard from the case, but that's not typical.
Before you blow dry your machine, you might look inside, around the
lower left corner, and see if any connectors have come loose. Also,
find an air compressor and blow out the dust, especially around the
fan.

There are YouTube videos showing how to use a hot air gun to reflow a
BGA.
https://www.youtube.com/results?search_query=hot+air+bga+reflow
Make sure you build a heat shield out of aluminum foil to prevent
melting nearby plastic parts. Practice on scrap PCB's before
attempting to fix the unspecified model Asus laptop. It's quite
difficult to tell if the low temperature solder balls have reflowed.
I'm undecided if liquid flux does anything useful.

Good luck.

Thanks for the advice Jeff. And the link. I did take this machine
apart once about 5 years ago to replace the hard drive. That all went
fine. Your "unspecified model ASUS" remark made me laugh because
when I was typing out the original message I realized I didn't have
the model number on hand and knew at the time that I really should
have included it with my post. I always seem to get caught.
Thanks Again,
Eric


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wrote in message ...

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric
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Default reflowing BGA with a hot air gun?

It's worth a go if the laptop is scrap otherwise.

Chances of success are extremely slim though.


The success stories you see on Youtube are either fake, or the tiny
percentage of these repairs that lasted long enough to make the video.



Gareth.







wrote in message ...

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric

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Default reflowing BGA with a hot air gun?

On 2/10/2018 2:03 PM, Gareth Magennis wrote:
It's worth a go if the laptop is scrap otherwise.

Chances of success are extremely slim though.


The success stories you see on Youtube are either fake, or the tiny
percentage of these repairs that lasted long enough to make the video.



Gareth.







wrote in message ...

I have a laptop that is acting really weird. It's an older ASUS,
probably ten or twelve years old. It was plugged in, closed, sitting
on a table. It worked fine a few days before the problems started. The
display keeps shaking. The machine takes forever to boot up. And then
acts weird. But if I push down hard on the lower left side of the
machine it works fine. As long as the pressure is kept up and in just
the right area.
I spoke to my son about this problem because he knows more about
this kind of thing than I do. He said it sounded like a video card
problem that he and some of his computer whiz friends have run into.
Apparently the video processor can get too hot and the BGA under it
can start to debond.
He has a hot air rework tool and he said I might be able to reflow
the chip. Is this something that a rank amateur can likely do?
Eric


I experimented with it on a laptop video chip.

I built a box with a square hole in the top. Put in air baffles
to point airflow at the hole.
Stuck a variable paint stripper in the side of the box.

Cleaned the area under the chip with repeated applications
of simple green, alcohol, water and lots of air. Dried it overnight
in a hot box at about 120F.
Used liquid flux designed for reflow repair under the chip.

Put thermocouples on the board and spaced it above the hole.

Adjusted the paint stripper to ramp the temperature of the bottom
of the board to just below the melting point of solder.
Aimed a temperature controlled air flow designed to desolder chips
at the unmasked area around the chip on the topside.
Heated the top of the chip to above the melting temperature
of solder. Used topside thermocouples, but today would probably
try a thermal imager.
Fixed the intermittent video problem.

Elated with my success, I tried another.
I had been using paper towels for insulation under the aluminum foil
topside mask. Got careless and set the paper towels on fire.
Putting out the fire jostled the board and some chips fell off
the backside. EPIC fail!

over the next year...
Third try fixed another laptop.

Fourth try didn't help that laptop.
Fifth try didn't help that laptop.

Laptops got so cheap at garage sales that reflowing
one wasn't worth trying.

YMMV

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On Thu, 08 Feb 2018 17:37:25 -0800, wrote:

Thanks for the advice Jeff. And the link. I did take this machine
apart once about 5 years ago to replace the hard drive. That all went
fine.


That's a start. However, to reflow the BGA chips on the motherboard,
you'll need to remove the motherboard from the plastic case. I take
photos as dive into the machine. Seems to impress (or panic) the
customer. For example:
http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/HP%20Envy%20m6%20A10%20CPU.html

Your "unspecified model ASUS" remark made me laugh because
when I was typing out the original message I realized I didn't have
the model number on hand and knew at the time that I really should
have included it with my post. I always seem to get caught.


That's a catch phrase that I use quite often. An amazing number of
people ask questions without supplying much in the way of identifying
the device they're trying to repair. If they're stuck on something,
they will describe what they've done, but not what problem they're
trying to solve. After many years, I suspect the problem is chronic.
Here's my magic formula for getting mostly sane answers on forums and
newsgroups:
1. What problem are you trying to solve? No history or product
reviews, just the problem.
2. What have you done so far and where are you stuck? What happened?
3. What do you have to work with? Maker, model, version, numbers.

This won't work for a laptop, but I've been successfully reflowing HP
Jetdirect cards in a toaster oven. So far, 18 working boards out of
20:
http://www.learnbydestroying.com/jeffl/pics/repair/BGA%20reflow/index.html
Also about 15 assorted HP printer PC boards and a few game boards.
Protecting plastic parts, that are easily melted, is the main problem.
Aluminum foil shields do not work, so I have to remove the parts. Most
everything else that can survive PCB soldering, can survive the
toaster oven reflow. Unfortunately, there are too many plastic parts
on a laptop motherboard, so it's not going to work.



--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


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Jeff:

Just did the 350F bake for 8 min for an HP P2015dn printer formatter PCB a few weeks ago. Gas oven. Level. Since there was a report of melting an Ethernet jack, I used 1/2 thick felt to protect it. I also removed the stickers. I did thermocouple the oven and did the overnight "do not disturb" thing after turning the oven off and opening the door. Worked great!
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Once upon a time on usenet Jeff Liebermann wrote:
On Thu, 08 Feb 2018 17:37:25 -0800, wrote:

Thanks for the advice Jeff. And the link. I did take this machine
apart once about 5 years ago to replace the hard drive. That all went
fine.


That's a start. However, to reflow the BGA chips on the motherboard,
you'll need to remove the motherboard from the plastic case. I take
photos as dive into the machine. Seems to impress (or panic) the
customer. For example:
http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/HP%20Envy%20m6%20A10%20CPU.html


I had to LOL at that. I have an HP Envy dv7 laptop that I don't use anymore
even though it's by far my most modern computer. Being an invalid with
chronic lower back pain vacuuming is one of the most crippling household
chores so it doesn't get done as often as I'd like.

The Envy has such a high air through-put that it doesn't take long to injest
enough dust to start causing problems. Also it's no IBM ThinkPad when it
comes to dis/assembly and has quite a few plastic tabs which won't handle
many cycles before breaking.

So I still use my ThinkPad T60 / 2GB RAM Win XP while my envy with i7 / full
HD display / 32GB SSD-accelerated 1TB HDD / 16GB RAM sits in a drawer. I
used it for a week or two but could tell that even in tat time and trying to
be careful of dust the airflow was reducing... This T60 pushes far less air
through and is simple to pull down once a year to clean the fan and fins.

I got the dv7 from a neighbour who offered it to me in return for data
recovery from it. (It got so hot that it wouldn't run for long, the RAM was
'cooked' and causing HDD corruption every time they tried to read from it
and it randomly shut down. I installed the new 16GB after I was happy there
was a good chance it would work again.) Maybe I'll get to use it when I
finally have to go into assisted living - if people still use laptops then.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

Your "unspecified model ASUS" remark made me laugh because
when I was typing out the original message I realized I didn't have
the model number on hand and knew at the time that I really should
have included it with my post. I always seem to get caught.


That's a catch phrase that I use quite often. An amazing number of
people ask questions without supplying much in the way of identifying
the device they're trying to repair. If they're stuck on something,
they will describe what they've done, but not what problem they're
trying to solve. After many years, I suspect the problem is chronic.
Here's my magic formula for getting mostly sane answers on forums and
newsgroups:
1. What problem are you trying to solve? No history or product
reviews, just the problem.
2. What have you done so far and where are you stuck? What happened?
3. What do you have to work with? Maker, model, version, numbers.

This won't work for a laptop, but I've been successfully reflowing HP
Jetdirect cards in a toaster oven. So far, 18 working boards out of
20:
http://www.learnbydestroying.com/jeffl/pics/repair/BGA%20reflow/index.html
Also about 15 assorted HP printer PC boards and a few game boards.
Protecting plastic parts, that are easily melted, is the main problem.
Aluminum foil shields do not work, so I have to remove the parts. Most
everything else that can survive PCB soldering, can survive the
toaster oven reflow. Unfortunately, there are too many plastic parts
on a laptop motherboard, so it's not going to work.




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On Fri, 16 Feb 2018 14:04:33 +1300, "~misfit~"
wrote:

Once upon a time on usenet Jeff Liebermann wrote:
On Thu, 08 Feb 2018 17:37:25 -0800, wrote:

Thanks for the advice Jeff. And the link. I did take this machine
apart once about 5 years ago to replace the hard drive. That all went
fine.


That's a start. However, to reflow the BGA chips on the motherboard,
you'll need to remove the motherboard from the plastic case. I take
photos as dive into the machine. Seems to impress (or panic) the
customer. For example:
http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/HP%20Envy%20m6%20A10%20CPU.html


Photo of the above heat pipe radiator AFTER I blew compressed air into
the area from the outside. The only way to get the crud out is to
tear it apart.
http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/clogged_fan.html

Also, this one way it could be easily cleaned:
http://www.learnbydestroying.com/jeffl/pics/repair/Dell%20Inspiron%201525/index.html
The bottom cover comes off exposing the entire heat pipe assembly,
which is then easily cleaned. Too bad Dell (or Foxcom) designed it
into a crappy machine (Inspiron 1525) with miserable BGA soldering.

More later. Gotta run.


--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default reflowing BGA with a hot air gun?

Once upon a time on usenet Jeff Liebermann wrote:
On Fri, 16 Feb 2018 14:04:33 +1300, "~misfit~"
wrote:

Once upon a time on usenet Jeff Liebermann wrote:
On Thu, 08 Feb 2018 17:37:25 -0800, wrote:

Thanks for the advice Jeff. And the link. I did take this machine
apart once about 5 years ago to replace the hard drive. That all
went fine.

That's a start. However, to reflow the BGA chips on the
motherboard, you'll need to remove the motherboard from the plastic
case. I take photos as dive into the machine. Seems to impress
(or panic) the customer. For example:
http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/HP%20Envy%20m6%20A10%20CPU.html


Photo of the above heat pipe radiator AFTER I blew compressed air into
the area from the outside. The only way to get the crud out is to
tear it apart.
http://www.learnbydestroying.com/jef...ogged_fan.html


The HP envy that I have likewise must be stripped down to where the top and
bottom shells are apart to clean the fan. This is what the fins looked like
when I finally got the
http://test.internet-webmaster.de/upload/1519009591.jpg
I was fully intending to cut a hole in the bottom case (and make a hinged
door with tape) so I could access the fan / fins for the frequent cleaning
it will require but the fan lifts out *upwards* and is half under the
keyboard.

(In that picture the heatpipe that you can see is the one from the GPU
that's already been past a smaller set of fins [out-of-shot to the right].
Behind that are the two heatpies that come directly from the 3GHz quad core
i7 CPUs heat collector.)

Also, this one way it could be easily cleaned:
http://www.learnbydestroying.com/jeffl/pics/repair/Dell%20Inspiron%201525/index.html
The bottom cover comes off exposing the entire heat pipe assembly,
which is then easily cleaned. Too bad Dell (or Foxcom) designed it
into a crappy machine (Inspiron 1525) with miserable BGA soldering.


I've not seen setups like that on recent machines. IMO manufacturers are
using 'heatsink clog' combined with difficulty of disassembly / reassembly
(with fragile plastic clips and ribbon cables) as a form of built-in
obsolescence. After all CPUs and SSDs aren't becoming obsolete /
underpowered as quickly as they once did...

More later. Gotta run.


Cheers,
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)


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The Envy has such a high air through-put that it doesn't take long to injest
enough dust to start causing problems.


get a piece of foam and make an external intake filter

much easier to clean an external filter

m



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On Mon, 19 Feb 2018 14:03:37 -0800 (PST), wrote:

The Envy has such a high air through-put that it doesn't take long to injest
enough dust to start causing problems.


get a piece of foam and make an external intake filter
much easier to clean an external filter
m


Won't work. The basic problem is that the typical laptop fan air
intake is on the bottom of the laptop, where it can play vacuum
cleaner and suck all the dust, hair, and food debris from the table
and into the fan. The fan then uses centrifugal force to launch all
this crud into the heat pipe fins, where they get stuck. Plugging the
intake with a filter might prevent clogging the downstream fins, but
just moves the problem to the intake filter, which can also become
clogged. Granted, an intake filter is easier to clean, but from
experience, nobody ever cleans the filters until they are totally
clogged.

A better solution would be to find a more protected air intake
location, such as on the top of the machine. That could be done with
a plenum or duct, but with todays ultra-thin laptops, there's no room.
Worse, most of the top is obstructed by the keyboard. There are a few
laptops that have the air intake on the side, and exhaust out the
back. Those don't clog as easily, but do tend to have larger cases.



--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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