Those of you with experience troubleshooting a dead
laptop, can you provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped working.
Do you have an idea how to do basic troubleshooting?

What happens when I try to reboot is that nothing shows
up on the 17-inch screen whatsoever.

The only indicators are the fan and a half dozen LEDs.

The fan is most notable.
When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

The white LED to the immediate left of the topside power
switch glows white when the computer is turned on.

The orange and white LED next to the power input on the
right side of the pc also glows either orange or white.

The white capslock key LED blinks white synchronously with
the NumLock key. The F12/WiFi function key glows orange.

The tiny LED on the DVD tray button does not light, nor
will the DVD tray open unless I insert a paperclip.

I found this "maintenance guide" but it doesn't seem to
list these conditions:
http://h10032.www1.hp.com/ctg/Manual/c02623152.pdf

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

Mainly I just want to know if I can pinpoint the failure
and then I can see whether it's worth trying to fix.

On Mon, 26 May 2014 03:28:54 +0000, Calia wrote:

When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

Actually, now that I have said that, my second timer run
shows the fan continually running.

So, to clarify, the only indications of anything working
are the fan runs continually, and a few LEDs light, as
stated prior.

Curiously, the hard disk drive LED light on the left
side does not seem to be lighting up at any point.

Calia wrote:

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped working.
Do you have an idea how to do basic troubleshooting?

Does it have a door you can remove to get to the memory card? if so,
remove the memory card, clean the contacts (gently) if they
appear dirty, and re-insert. You might blow dirt out of the
connector before putting the memory card back in.

Otherwise, some computers have various connectors between various
components, and some of these can work loose with handling. There's
always a connector for the LCD screen, but these are likely very
hard for a non-expert to get into. You might also pull the hard
drive and re-insert. Sometimes that will fix a problem, although
you'd usually get a failure message when it can't read the hard
drive.

Jon

In article , lid says...

On Mon, 26 May 2014 03:28:54 +0000, Calia wrote:

When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

Actually, now that I have said that, my second timer run
shows the fan continually running.

So, to clarify, the only indications of anything working
are the fan runs continually, and a few LEDs light, as
stated prior.

Curiously, the hard disk drive LED light on the left
side does not seem to be lighting up at any point.

Ugh!!! I take it it's not under warranty? Even with the hard disk toast
I'd expect to see the display come alive. Has the power brick given up?
That's about only test I can suggest, e.g. is it providing 12 volts or
whatever. Try to find another rated more or less same and try it
instead.

Other than that if it's not under warranty and you can't find some
"specialty shop" deals with laptops almost exclusively you likely have
some parts is about it, e.g. hard disk can likely be used in some
enclosure as an external drive etc. Fact of the matter is cost of time
to repair likely comes close to cost of replacing. Sorry for your loss.

Calia wrote in
:

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped
working. Do you have an idea how to do basic
troubleshooting?

What happens when I try to reboot is that nothing shows
up on the 17-inch screen whatsoever.

The only indicators are the fan and a half dozen LEDs.

The fan is most notable.
When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

The white LED to the immediate left of the topside power
switch glows white when the computer is turned on.

The orange and white LED next to the power input on the
right side of the pc also glows either orange or white.

The white capslock key LED blinks white synchronously with
the NumLock key. The F12/WiFi function key glows orange.

The tiny LED on the DVD tray button does not light, nor
will the DVD tray open unless I insert a paperclip.

I found this "maintenance guide" but it doesn't seem to
list these conditions:
http://h10032.www1.hp.com/ctg/Manual/c02623152.pdf

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

Mainly I just want to know if I can pinpoint the failure
and then I can see whether it's worth trying to fix.


Bad RAM will stop boot too.

On Mon, 26 May 2014 03:28:54 +0000 (UTC), Calia
wrote:

I have a Windows 7 HP G72 laptop which suddenly stopped working.

Jumping to a premature conclusion, I would guess(tm), that you have
the same problem as all these people:
https://www.google.com/#q=hp+g72+laptop+will+not+turn+on
Usually, it's bad BGA chip soldering.

Do you have an idea how to do basic troubleshooting?

Unplug the charger. Remove the battery. Go away for about 10
minutes. Put the battery back in and do not plug in the charger. If
the battery is totally dead (i.e. shorted from sitting at zero charge
for too long), it might not turn on. If you suspect that you have a
shorted battery, and can't find a suitable replacement, remove the
battery, insert the charger, and see if it will power on with just the
charger.

What happens when I try to reboot is that nothing shows
up on the 17-inch screen whatsoever.

That might be an HP G72-227WM. Is that correct? (Complete and
accurate model numbers are always helpful).

The only indicators are the fan and a half dozen LEDs.

The fan is most notable.
When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

Ummm... It should go at full blast for about 2 seconds, and then spin
slowly. 40 seconds implies that some timer on the MB is not working
normally.

The white LED to the immediate left of the topside power
switch glows white when the computer is turned on.

OK, the power switch is working. Is there anything on the screen? If
not, take a flashlight and shine it around the upper left of the
screen, where the BIOS boot messages appear, or in the center of the
screen, where the Windoze logo normally appears. If you see
something, then the backlighting is blown. The G72-227WM has an LED
backlight, so there's no inverter to replace. The problem will be to
determine if the lack of backlighting is caused by a problem on the
motherboard, LCD panel, cable, or connector.

The orange and white LED next to the power input on the
right side of the pc also glows either orange or white.

White means it has power. Orange means it's charging. No light means
that it's charged. Flashing means your battery is so low as to not be
able to power the laptop.

The white capslock key LED blinks white synchronously with
the NumLock key. The F12/WiFi function key glows orange.

HP Blinkenlighten codes:
http://h10010.www1.hp.com/ewfrf/wc/document?lc=en&dlc=en&cc=us&docname=c01732674&prod uct=1132551#N213
This should give you some things to check.

The tiny LED on the DVD tray button does not light, nor
will the DVD tray open unless I insert a paperclip.

I found this "maintenance guide" but it doesn't seem to
list these conditions:
http://h10032.www1.hp.com/ctg/Manual/c02623152.pdf

That's meant for users, not techs.

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

Yes, I can. Try asking in the HP support forums:
http://h30434.www3.hp.com/t5/Notebook-Hardware/bd-p/Hardware
Hint: You'll need to provide a better description of the flashing
lights and boot errors.

Mainly I just want to know if I can pinpoint the failure
and then I can see whether it's worth trying to fix.

In my never humble opinion, the last few years of HP and Compaq laptop
are not worth fixing. I hesitate to fix them because they don't stay
fixed. I often see them back in a few months, usually with a
different problem. Details and horror stories on request.

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

On Mon, 26 May 2014 00:50:51 -0300, pjp wrote:

I take it it's not under warranty?
The warranty died long ago.

Even with the hard disk toast, I'd expect to see the display come alive.
Nothing shows up on the display.
Here is a picture with the power on and the fan running:
http://oi59.tinypic.com/2h3a3oz.jpg

Has the power brick given up?
I don't know. I will try to get test leads into those tiny holes.
It appears to be charging the battery and the battery appears to
work, so, I've tested all three cases:
a) With just the battery
b) With the AC power and the battery in
c) With the AC power and the battery out

http://oi61.tinypic.com/2lj6bdv.jpg

On Sun, 25 May 2014 22:40:42 -0500, Jon Elson wrote:

Does it have a door you can remove to get to the memory card?

It's a little tricky removing those memory cards.
They seem to have a fancy "clasp" on the sides, but, I will
keep trying until I get them out:
http://oi61.tinypic.com/hsmiqc.jpg

You might also pull the hard drive and re-insert.
I am taking your advice and have removed the hard
drive, and will re-insert soon:
http://oi60.tinypic.com/5wbfa8.jpg

On Mon, 26 May 2014 04:18:13 +0000, Calia wrote:

It's a little tricky removing those memory cards.

I removed the two memory cards, and swapped them, and put
them back, and powered up, but to no avail.

http://oi57.tinypic.com/73h4rm.jpg

On Sun, 25 May 2014 21:13:55 -0700, Jeff Liebermann wrote:
(Complete and accurate model numbers are always helpful).

My mistake. I apologize.

Inside the battery bay is the model & product number:
Model G72 B54NR
Product XR826UA#ABA

Usually, it's bad BGA chip soldering.
I had to look up Ball Grid Array, which, when I found what it
was, looked far beyond my capabilities.

Is there anything on the screen?
Nothing.

not, take a flashlight and shine it around the upper left of the
screen, where the BIOS boot messages appear

Tried that. Nothing that I can see.

HP Blinkenlighten codes:

Thanks Jeff.
I had no idea those keys were blinking a code!
I followed the procedure at the suggested location:
http://h10010.www1.hp.com/ewfrf/wc/d...t=1132551#N213

Basically, I removed the power & battery & discharged the computer
by holding the power button down for 30 seconds and then hooked
just the AC power but not the battery.

1. The AC adaptor light at the right side goes white.
2. The capslock & numlock light stays white (i.e., no blinking).
3. The F12 is a steady orange.
4. I press the POWER switch.
5. I hear the fan but not the HDD nor do I hear any beeping.
6. The AC adaptor light on the side of the PC stays white.
7. The capslock & numlock keys blink once for 1 1/2 seconds,
and then they go off for 4 1/2 seconds.
8. I can discern no other pattern than that 1.5:4.5 seconds!

The really bad news is that a single blink in the table reads:
"CPU not functional"

Is that as horrible as it sounds?

On Mon, 26 May 2014 05:06:15 +0000, Calia wrote:

The really bad news is that a single blink in the table reads:
"CPU not functional"

I found this video which at least shows me how to disassemble
the HP G72 B54NR to get at the CPU to see if it can be debugged:
http://www.youtube.com/watch?v=VXrXMSOShA0

Calia wrote:
On Mon, 26 May 2014 04:18:13 +0000, Calia wrote:

It's a little tricky removing those memory cards.

I removed the two memory cards, and swapped them, and put
them back, and powered up, but to no avail.

http://oi57.tinypic.com/73h4rm.jpg


You test the memory SODIMMs, one at a time.

Do not insert both.

Try only one of them.

If still a problem, remove that one and try the other.
It is unlikely for them to both fail at the
same time (although that has happened to me).

Paul

Calia wrote:
Those of you with experience troubleshooting a dead
laptop, can you provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped working.
Do you have an idea how to do basic troubleshooting?

What happens when I try to reboot is that nothing shows
up on the 17-inch screen whatsoever.

The only indicators are the fan and a half dozen LEDs.

The fan is most notable.
When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

The white LED to the immediate left of the topside power
switch glows white when the computer is turned on.

The orange and white LED next to the power input on the
right side of the pc also glows either orange or white.

The white capslock key LED blinks white synchronously with
the NumLock key. The F12/WiFi function key glows orange.

The tiny LED on the DVD tray button does not light, nor
will the DVD tray open unless I insert a paperclip.

I found this "maintenance guide" but it doesn't seem to
list these conditions:
http://h10032.www1.hp.com/ctg/Manual/c02623152.pdf

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

Mainly I just want to know if I can pinpoint the failure
and then I can see whether it's worth trying to fix.


Black screen with blinking error code LEDs are described here.

Try to match the table info, to your machine. Applies to
UEFI BIOS machines.

http://h10025.www1.hp.com/ewfrf/wc/d...s&dlc=en&lc=en

And this is my proof that a G72 may be using a UEFI BIOS.

http://h10025.www1.hp.com/ewfrf/wc/s...293043&os=4062

Paul

On Sun, 25 May 2014 21:13:55 -0700, Jeff Liebermann wrote:

Usually, it's bad BGA chip soldering.

I will likely try overheating the motherboard, to solve
this problem, as per this video on the HP G72:
http://www.youtube.com/watch?v=IgH98o3cu0A

On Mon, 26 May 2014 01:29:41 -0400, Paul wrote:

Try to match the table info, to your machine. Applies to
UEFI BIOS machines.

http://h10025.www1.hp.com/ewfrf/wc/d...s&dlc=en&lc=en

I get a single blink, which translates to:
LEDs blink 1 time, CPU, CPU not functional

It seems the CPU disconnects from the motherboard due to solder
cracks, at least if I understand Jeff correctly.

Calia wrote:
On Mon, 26 May 2014 01:29:41 -0400, Paul wrote:

Try to match the table info, to your machine. Applies to
UEFI BIOS machines.

http://h10025.www1.hp.com/ewfrf/wc/d...s&dlc=en&lc=en

I get a single blink, which translates to:
LEDs blink 1 time, CPU, CPU not functional

It seems the CPU disconnects from the motherboard due to solder
cracks, at least if I understand Jeff correctly.

Not necessarily true. It could be the VCore regulator
near the CPU socket which is not functioning. It could
be a loss of power feeding into the VCore regulator (like
a problem with the circuit distributing power from battery
to elsewhere inside the computer).

CPU/Processor chips are very reliable.

On laptops with a separate GPU chip, some of those have
problems with cracked solder balls. But for the
CPU socket, it could be using a thruhole socket
with land grid array springs to make contact with
the CPU. And that doesn't have nearly the same issues
as a fine pitch BGA might.

Also, when you see LEDs blink, they may not be
blinking due to the "test procedure". They could
instead blink because of the way a power failure
is happening inside the unit. For the entries in the
table with multiple blinks, seeing the LED blink
multiple times would be a reasonably reliable
indication of a problem. But when you see one blink,
is that a "CPU test failure", or is it "the power
regulator just turned off". We don't know. Some
test results will not be that accurate and specific.
And it would be a mistake to jump to a conclusion just
yet.

I would retest with battery pack IN versus
battery pack OUT, and see if the timing of the
blink changes at all. If if was a true CPU
test failure, the timing should not change at all.
If the blink duration seems quite different,
between those two test cases, it could be an
internal power distribution issue.

Paul

On Mon, 26 May 2014 05:29:51 +0000, Calia wrote:

I will likely try overheating the motherboard

If the overheating of the motherboard doesn't work, is it
feasible to remove the motherboard and somehow, "reflow"
the solder joints?

For example, in this video, a guy removes & replaces
a chip with some sort of brass torch tool:
http://www.youtube.com/watch?v=zHpeLYb-puw

Is the IC replacement as easy as that video makes it seem?
(Seems to me the chances of getting all the pins lined
up and nothing shorted elsewhere has got to be near zero.)

Calia wrote:
On Mon, 26 May 2014 05:29:51 +0000, Calia wrote:

I will likely try overheating the motherboard

If the overheating of the motherboard doesn't work, is it
feasible to remove the motherboard and somehow, "reflow"
the solder joints?

For example, in this video, a guy removes & replaces
a chip with some sort of brass torch tool:
http://www.youtube.com/watch?v=zHpeLYb-puw

Is the IC replacement as easy as that video makes it seem?
(Seems to me the chances of getting all the pins lined
up and nothing shorted elsewhere has got to be near zero.)


You use a hot air rework station for BGA replacement.

http://product-image.tradeindia.com/...ation-G500.jpg

On good quality PCB material, a BGA site can be repaired
up to three times, without damage to the PCB.
Computer motherboards are not high quality,
so your mileage may vary.

The hot air rework, applies heat from the top
of the PCB. It also applies heat from the bottom.
This is to reduce stress on the PCB. On the top side,
the area to be heated, is controlled by fitting
a metal "hood" to the nozzle. There are different
sized hoods for different sized chips. (We had
at least 20 different ones for our machine at work.)

On the top side, a "vacuum wand" can be used to lift
the molten-hot chip off its PCB site. That's when it is
hot enough. The small knob on top of the tool in
the picture above, could be related to chip release.

When you put down a new chip, the soldering process
is "self aligning". When the new chip is heated, to make
the solder balls melt, the surface tension of the solder
helps "attract" each contact, to its mate on the PCB.
So even if the chip is rotated 1 degree from ideal
position, it will "snap" into position when the
solder melts. This reduces soldering defects to around
1 bad connection in 100,000 solder balls.

When a repair is finished, a 2.5D Xray machine can be
used to verify the quality of the solder joints.
Pictures are taken, using Xray energy, at an angle off
the vertical axis. And any balls with a "popcorn" problem,
can be seen in the picture taken with the Xray energy.
I've never seen one of these in person, but our factory
had one. Every large chip was verified with one of these
(as part of closed loop process feedback). Eventually,
once all the kinks are worked out of the manufacturing
process, this might not be as necessary.

http://www.koreaittimes.com/story/28...uality-control

A company in town used to do this repair here, but
they charge $1000 per chip. They have this high charge,
because their staff are mostly idle. And the company
has likely long since closed up and moved. In Taiwan,
where staff do this for a solid eight hours a day, the
cost of repair is a lot lower.

Depending on the ball count, pitch, and so on,
there may also be "underfill" materials squirted
underneath the chip. This forms a solid which helps
control stress when the product is at its normal
operating temperature. I know nothing about how
you deal with underfill, when such a chip needs
a repair. Underfill would be a popular solution
for stand-alone GPU chips. (I don't even know
what materials to use, so this is just an illustration.)

http://www.namics.co.jp/e/product/chipcoat03.html

*******

Home computer repair people, they use the "oven
method" to repair GPUs. Which is about as dumb
and dangerous as it sounds. While the repair
may seem to work at first, the track record
of such repairs is not perfect. Temperature
profile is completely uncontrolled - plastics
may melt on items which were not intended for
this sort of treatment. Proper repair with a hot
air rework station is better, because the temperature
profile is controlled during the entire operation. You
can use the chip manufacturer recommended profile,
when doing a repair.

Paul

On Mon, 26 May 2014 01:50:09 -0400, Paul wrote:

I would retest with battery pack IN versus
battery pack OUT, and see if the timing of the
blink changes at all.

The timing of the single blink remains whether I use the
battery or the AC power supply without the battery.

I am googling how to reflow the motherboard and it looks
like I have three major options (none of which are really
all that good).

1. Cover all fan ports & run the PC hot for 20 minutes.
2. Disassemble & reheat specific chips (e.g., cpu).
3. Disassemble & bake motherboard in the kitchen oven.

None seem particularly safe.

On Mon, 26 May 2014 06:53:56 +0000, Calia wrote:

3. Disassemble & bake motherboard in the kitchen oven.

Here is the procedure I may need to follow:
http://www.computerrepairtips.net/ho...p-motherboard/

On Mon, 26 May 2014 05:06:15 +0000 (UTC), Calia
wrote:

On Sun, 25 May 2014 21:13:55 -0700, Jeff Liebermann wrote:
(Complete and accurate model numbers are always helpful).

My mistake. I apologize.

Inside the battery bay is the model & product number:
Model G72 B54NR
Product XR826UA#ABA

Thanks.

Usually, it's bad BGA chip soldering.

I had to look up Ball Grid Array, which, when I found what it
was, looked far beyond my capabilities.

It's not impossible to do SMT repairs, but it does help to have the
right equipment and plenty of practice. Also, if you're replacing
parts, it might be helpful to have a supply of known good
replacements. Cannibalism from other motherboards works in
desperation, but is not a good idea. I use a Chinese hot air SMT
workstation that I bought cheap on eBay for about $80. Make sure you
get a good selection of nozzles. The video you mentioned should have
had some aluminum foil around the chip to prevent the hot air from
melting nearby parts and plastic.

While this may be above your present abilities, I suspect that
throwing money at the laptop is not going to work because it will
probably cost as much as the laptop is worth to fix it. Big and
awkward 17" laptops, with only 1600x900 displays and a slow CPU, are
not exactly in demand. In the past, I've removed the motherboard, and
sent it off to a random reballing service:
www.ebay.com/sch/i.html?_nkw=g72+motherboard+repair+service
It usually cost me about $150 plus about $20 shipping each way. Add 2
hrs of my labor to tear it down, and put it back together, and I'm
well over the value of the machine.

I had no idea those keys were blinking a code!
I followed the procedure at the suggested location:
http://h10010.www1.hp.com/ewfrf/wc/d...t=1132551#N213

Basically, I removed the power & battery & discharged the computer
by holding the power button down for 30 seconds and then hooked
just the AC power but not the battery.

1. The AC adaptor light at the right side goes white.
2. The capslock & numlock light stays white (i.e., no blinking).
3. The F12 is a steady orange.
4. I press the POWER switch.
5. I hear the fan but not the HDD nor do I hear any beeping.
6. The AC adaptor light on the side of the PC stays white.
7. The capslock & numlock keys blink once for 1 1/2 seconds,
and then they go off for 4 1/2 seconds.
8. I can discern no other pattern than that 1.5:4.5 seconds!

The really bad news is that a single blink in the table reads:
"CPU not functional"

Is that as horrible as it sounds?

It's unlikely to be the CPU. I haven't seen a dead Intel CPU for
maybe 10 years, and only a few older AMD Athelon chips that blow up
when the heat sink is dislodged. The CPU is in a socket so you can
easily replace the CPU. Photos:
http://www.ascendtech.us/hp-615849-001-g72-series-motherboard_i_mbhp61584901g72.aspx
The big white socket is for the CPU, which appears to be an Intel
2.0GHz P6100. Cheap.
www.ebay.com/sch/i.html?_nkw=Intel+P6100
From your detailed description (thanks), it looks like 1 flash, which
means "CPU not functional". More likely, it's one of the other chips
holding down the address or data lines causing the CPU to misbehave. I
can't tell from here which chip without poking my scope onto the
address and data lines.

One thing you can do is buy|borrow|steal a hot air SMT workstation and
get some practice on this machine. Well, practice on some old boards
first to get a feel for how much heat is needed and for how long.
However, don't try to remove the chip. Just slop on a mess of paste
flux, and heat it until the solder reflows. Maybe push LIGHTLY on the
chip to get it closer to the PCB. If the astronomical signs are in
your favor, you might end up with a usable board. If not, you won't
be any worse than you started, and maybe you can do better on the next
motherboard. Or just use it as a cat warmer:
http://www.11junk.com/jeffl/pics/drivel/slides/Cat-warmer.html



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

On Mon, 26 May 2014 06:53:56 +0000 (UTC), Calia
wrote:

1. Cover all fan ports & run the PC hot for 20 minutes.

The theory is that since the BGA chips use low temperature (bismuth)
solder balls, it doesn't take much heat to reflow the solder. The
reality is that without flux, the broken solder connections are
unlikely to fuse together.

2. Disassemble & reheat specific chips (e.g., cpu).

The CPU is in a socket. Buy a cheap replacement on eBay and try it.

3. Disassemble & bake motherboard in the kitchen oven.

That will melt all the plastic parts (i.e. connectors). Bad idea.

There's a 4th option. Send it to someone with the expertise and
equipment.
www.ebay.com/sch/i.html?_nkw=g72+motherboard+repair+service
Just watch your costs very carefully.

None seem particularly safe.

Well, they're a step above the Xbox repairs that use a sterno can
under the PCB to reflow the solder.

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

Calia wrote:
On Mon, 26 May 2014 06:53:56 +0000, Calia wrote:

3. Disassemble & bake motherboard in the kitchen oven.

Here is the procedure I may need to follow:
http://www.computerrepairtips.net/ho...p-motherboard/


If you're serious about doing that, *don't* use the
oven that you use to prepare food.

Find a used toaster oven, keep it outdoors while
attempting the repair. The stink of melted plastic or
burned materials will stay with your used toaster oven,
while the family food oven is kept safe.

In an industrial setting, the duration (hold time) and
temperatures are all strictly controlled.

http://www.ami.ac.uk/courses/topics/...bapws_imgb.gif

As the posters note in your article above, if you heat the
entire motherboard, the electrolytic capacitors could
suffer. This is why a real re-work station uses a hood,
so the hot air only goes to the chip being repaired. If you
own a hot air gun, you can make a home made hood out of sheet
metal. For temperature monitoring, you could use a
thermocouple connected to a multimeter.

http://en.wikipedia.org/wiki/Thermocouple

Paul

Most likely an inverter failure.
..

Calia wrote:
Those of you with experience troubleshooting a dead
laptop, can you provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped working.
Do you have an idea how to do basic troubleshooting?

What happens when I try to reboot is that nothing shows
up on the 17-inch screen whatsoever.

The only indicators are the fan and a half dozen LEDs.

The fan is most notable.
When I press the power switch, the fan goes on for what
I timed at 40 seconds. Then the fan goes off.

The white LED to the immediate left of the topside power
switch glows white when the computer is turned on.

The orange and white LED next to the power input on the
right side of the pc also glows either orange or white.

The white capslock key LED blinks white synchronously with
the NumLock key. The F12/WiFi function key glows orange.

The tiny LED on the DVD tray button does not light, nor
will the DVD tray open unless I insert a paperclip.

I found this "maintenance guide" but it doesn't seem to
list these conditions:
http://h10032.www1.hp.com/ctg/Manual/c02623152.pdf

Those of you with experience troubleshooting a dead
laptop, can you provide advice?

Mainly I just want to know if I can pinpoint the failure
and then I can see whether it's worth trying to fix.


You have received a lot of useful information and suggestions, so what I
am about to say may be for naught: I have two G72 laptops. One I
bought new and experienced much the same type of problem as you are
after the warranty ran out. Being that I am one who cannot accept a
device is not repairable, I dug into trouble shooting and repairing my
laptop. At first I opened it up and inspected the connections because
the problem was intermittent. I would disassemble the computer,
reassemble it, and it would work for a time. Then it would fail again.
Without going into great detail of all the steps, the solution to
fixing this computer was to re-solder the connections at the power
switch board. There appears to be an opto isolator on a daughter board
where the switch is mounted. It takes a steady hand and a low wattage
iron, but this computer has not failed in a couple of years since I
touched up the connections. I think I fixed it.

After having fixed the above computer, I purchased another G72 computer
on Ebay where the seller was encountering the same failure as mine. I
bought it for little, and thought I would use it for parts if my
computer ever failed. When I received it, it DID NOT include an AC
adapter. I plugged in my adapter to the computer and everything
worked!! That has been over a year now.

So what can one learn from the above? First off there appears to be
some experiencing such failures that are attributed to the power switch
board. There are such posts on the web. Second, if the adapter
delivers less than the proper level of voltage to the computer, it too
will fail in a similar manner. Measuring the voltage with a volt meter
is not going to work unless you load it down sufficiently. If it were
my computer, I would borrow a power adapter that you know works on that
model computer. If it does not solve the problem, suspect the power
switch board.

There are no guarantees as to what will solve your problem, and the fan
running seems to contradict my experience, but a lot is happening when
you start a computer. Any of them failing will negate the boot process.
Good luck.

On Mon, 26 May 2014 04:48:06 +0100, Good Guy wrote:

Does it boot up with from a CD drive? I suggest put in your Windows 7
DVD and see if it boots up with it.

Just because I could, I tried booting to Knoppix, but it didn't even
get to the BIOS screen, which, if the CPU is reporting itself bad,
would be the case.

I don't think Windows 7 would fare any better, but, I don't have a
Windows 7 boot disk anyway.

On Mon, 26 May 2014 03:28:54 +0000, Calia wrote:

Those of you with experience troubleshooting a dead laptop, can you
provide advice?

I have a Windows 7 HP G72 laptop which suddenly stopped working. Do you
have an idea how to do basic troubleshooting?

What happens when I try to reboot is that nothing shows up on the
17-inch screen whatsoever.

The only indicators are the fan and a half dozen LEDs.

Before you have disassembled anything, shine a flashlight (electric torch)
at the screen, and watch closely as you power up. Maybe just the backlight has
failed.

On Mon, 26 May 2014 09:40:34 -0400, Wolf K wrote:

your _first_ concern should be to get all your
data off the disk drive

This is good advice, as had been all the prior advice.

I am heading down to Radio Shack today, if they're open, to pick
up an SATA/ATA USB adapter, which will make it very easy to get
all the data off the hard disk drive.

I've done that step before, and, even better, I recently
made a backup of my data hierarchy only about a month
ago, so there really isn't much data that I need to
back up incrementally anyway.

On Mon, 26 May 2014 14:44:02 +0000, Wond wrote:

Before you have disassembled anything, shine a flashlight (electric torch)
at the screen, and watch closely as you power up. Maybe just the backlight has
failed.

I tried that, and saw nothing. Even in the dark.

I think the single blink of the numlock and capslock indicating a bad CPU
(or the power to it) is the issue.

Most people here seem to indicate that the CPU itself didn't fry, but,
that the solder joints honeycombed, and eventually cracked.

At least that's what I seem to have gotten so far out of the
conversation.

In article , lid says...

On Mon, 26 May 2014 14:44:02 +0000, Wond wrote:

Before you have disassembled anything, shine a flashlight (electric torch)
at the screen, and watch closely as you power up. Maybe just the backlight has
failed.

I tried that, and saw nothing. Even in the dark.

I think the single blink of the numlock and capslock indicating a bad CPU
(or the power to it) is the issue.

Most people here seem to indicate that the CPU itself didn't fry, but,
that the solder joints honeycombed, and eventually cracked.

At least that's what I seem to have gotten so far out of the
conversation.

The manufacturer's site may have some info on what you "see" and "hear"
depending on what's wrong. Least used to be "x" beeps meant this and
"y" beeps meant that type idea, maybe lights do similar?

Internal power supply likely provides a number of leads with varying
power. Could be it's failed on one or more of them but not all hence see
leds lit on some keys?

Again an experienced shop would know how to test all that, I don't. I
also don't really like taking laptops apart IF I also have to put it
back together and have it run I solder with a blowtorch LOL

On Mon, 26 May 2014 17:37:55 +0000 (UTC), Calia
wrote:

On Mon, 26 May 2014 09:40:34 -0400, Wolf K wrote:

your _first_ concern should be to get all your
data off the disk drive

This is good advice, as had been all the prior advice.

I am heading down to Radio Shack today, if they're open, to pick
up an SATA/ATA USB adapter, which will make it very easy to get
all the data off the hard disk drive.

I've done that step before, and, even better, I recently
made a backup of my data hierarchy only about a month
ago, so there really isn't much data that I need to
back up incrementally anyway.

That probably will work, especially since the drive is not failing and
there's little risk of losing anything on it.

In the future, you might consider doing an image backup instead. I
use Acronis True Image 2014, but there are free drive cloning programs
that will also work:
http://clonezilla.org
Some of the benefits of image backups a
- Speed. I just did an SSD to USB 3.0 backup running at 6
GBytes/minute. Typcial for older machines and USB 2.0 is 1-2
GBytes/minute backup.
- It backups up literally everything. Nothing is missed. That's
great for programs the dump files in unusual places or strange stuff
in hidden partitions. Also works with UEFI boot.
- In this case, it will also get the recovery partition, which you
might need for a reinstall. The alternative is to order the recovery
DVD's from HP (about $30).
- etc...

I'm at the point that everything that is brought to the shop usually
gets backed up twice; once on arrival and once when it's done.
http://802.11junk.com/jeffl/crud/backup-drives.jpg
That's about 6TB of drives show. There is probably another 5TB of
drives that I've since the picture was taken. What makes this
practical is the speed of the backup (and restore).

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

"Calia" wrote in message ...

I am heading down to Radio Shack today, if they're open,
to pick up a SATA/ATA USB adapter, which will make it very
easy to get all the data off the hard disk drive.

If you're near a computer-supply store, you might want to look for Vantec. I
can recommend them from personal experience.

www.vantecusa.com

In message , Calia
writes:
On Mon, 26 May 2014 05:29:51 +0000, Calia wrote:

I will likely try overheating the motherboard

If the overheating of the motherboard doesn't work, is it
feasible to remove the motherboard and somehow, "reflow"
the solder joints?

For example, in this video, a guy removes & replaces
a chip with some sort of brass torch tool:
http://www.youtube.com/watch?v=zHpeLYb-puw

Is the IC replacement as easy as that video makes it seem?
(Seems to me the chances of getting all the pins lined
up and nothing shorted elsewhere has got to be near zero.)

Yes and no; it takes practice!

Step by step through that video:

melting the solder on the pins of the IC with a hot air blower.
Personally, I'd have some Kapton tape (like the yellow tape visible near
the top of the video around just after 7 minutes in) over the other
small components around: not so much as to keep them in place - if
they're decoupling capacitors, it _might_ not matter too much if they're
lost - as to stop them going off and shorting something else. It's easy
not to detect these almost microscopic components.

Removing the IC. I'm pretty certain there was a skip in the video, as it
seems to disappear by magic - one moment it's there, the next it isn't.
The most important thing is to make sure all the solder is really
melted: if it isn't at just one or two pins, you can pull off tracks
(which are the devil to repair) when you pull the IC off. Ideally it
will just blow away.

Cleaning up the solder pads. That's what he's doing with the solder
braid (the copper woven strip) and soldering iron. Basically, you want
to clean the pads until they're flat, no solder (other than a very thin
flat layer).

Applying solder and replacement chip. It looks like he applied solder
and then reheated it all with the hot air again. I'm sure that can be
made to work; the way I usually do it is manually tack two opposing legs
to hold the chip in place, then go around chasing a blob of solder
around the remaining legs: amazingly, this does work, if the
solder-resist is in reasonably condition. Lining the chip up before
tacking is the difficult bit - doable, just takes patience (and a second
or third try if it moves during the tacking: you just have to groan and
do it, don't go ahead and assume you can fix it after you've soldered
_all_ the legs).

The second half of the video seems to be replacing a surface-mount
connector, by much the same means, though I think he does use tacking
this time.

I'd agree with those expressing doubt as to whether it's worth it, and
try with an external monitor first.

(Also, my own - extremely limited! - experience of laptop repair has
been that cracks - in the solder joints or the PCB tracks around them -
in the vicinity of the power input connector can be the problem: and
lights can still come on, just there isn't enough power getting through
to do anything else. If it gets to a dismantling and possible soldering
activity, I'd reflow the solder around those before anything else: a lot
easier than the finer chips. My experience replacing chips is genuine
[avionics], but not with laptops. And I wouldn't expect to be able to
reflow a ball-grid array.)
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

he was eventually struck off by the BMA in 1968 for not knowing his gluteus
maximus from his humerus.

On Mon, 26 May 2014 11:49:48 -0700, "William Sommerwerck"
wrote:

"Calia" wrote in message ...

I am heading down to Radio Shack today, if they're open,
to pick up a SATA/ATA USB adapter, which will make it very
easy to get all the data off the hard disk drive.

If you're near a computer-supply store, you might want to look for Vantec. I
can recommend them from personal experience.
www.vantecusa.com

This model?
http://www.vantecusa.com/en/product/view_detail/586
$27 from NewEgg.
http://www.newegg.com/Product/Product.aspx?Item=N82E16812232033
Ouch. Note that I'm buying USB 3.0 these days because it's becoming
common and the speed improvement is worthwhile.

Cheaper on eBay:
http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&LH_BIN=1&_nkw=usb+3.0+SA TA+adapter&rt=nc&LH_PrefLoc=3





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

On Tue, 27 May 2014 00:00:05 +0100, J. P. Gilliver (John) wrote:

melting the solder on the pins of the IC with a hot air blower.

I was wondering what that was, as he seemed too close for it
to be a flame burner.

On Tue, 27 May 2014 00:00:05 +0100, J. P. Gilliver (John) wrote:

I'd have some Kapton tape (like the yellow tape visible near
the top of the video around just after 7 minutes in) over the other
small components around:

I had never heard of this "kapton" tape!

Googling, I'm still not sure what it is, but it must be a great
insulator.
http://en.wikipedia.org/wiki/Kapton

On Tue, 27 May 2014 00:00:05 +0100, J. P. Gilliver (John) wrote:

I'd agree with those expressing doubt as to whether it's worth it, and
try with an external monitor first.

I hadn't even thought of that!

It's a great idea.

I have one at work, which I can test out tomorrow!

Thanks!

"Calia" wrote in message ...

I had never heard of this "kapton" tape!

My heavens! Stephen Foster wrote a song about it in the 19th century -- "De
Kapton Races"!

"Oh, de Kapton ladies sing dis song --
Doo-dah, doo-dah.
De Kapton racetrack five miles long --
Oh, de doo-dah day."


Googling, I'm still not sure what it is, but it must be
a great insulator.

Kapton has been used to make orthodynamic loudspeakers. It's also used to
cover waveguide ports, so the nitrogen within won't get without. (The
waveguides are filled with dry nitrogen to keep moisture out.)

In message , Calia
writes:
On Tue, 27 May 2014 00:00:05 +0100, J. P. Gilliver (John) wrote:

melting the solder on the pins of the IC with a hot air blower.

I was wondering what that was, as he seemed too close for it
to be a flame burner.

It's generally a thing not unlike a very specialised (usually with a
temperature control) hair-dryer. You can get assorted nozzles, some
shaped to suit devices; the one I think he was using was just the one
that reduces the nozzle diameter to about a third, which gives a more
directable stream (but you have to move it about more).

I think a flame burner would pollute the environment (I mean the board
and components, not the planet) too much: you really need a fairly clean
environment for fine solder, flux, and solder-resist all to work as
they're supposed to.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

TV and radio presenters are just like many people, except they tend to wear
make-up all the time. Especially the radio presenters. - Eddie Mair, in Radio
Times 25-31 August 2012

In message , Calia
writes:
On Tue, 27 May 2014 00:00:05 +0100, J. P. Gilliver (John) wrote:

I'd have some Kapton tape (like the yellow tape visible near
the top of the video around just after 7 minutes in) over the other
small components around:

I had never heard of this "kapton" tape!

Googling, I'm still not sure what it is, but it must be a great
insulator.
http://en.wikipedia.org/wiki/Kapton

I must admit I was just using the name those who taught me PCB rework
used, though I _think_ it's correct. (The Wiki article doesn't mention
this specific use.) Though not perfect - the adhesive tends to weaken a
little under the great heat (and fair amount of wind!) required when
removing a largish chip - it does a pretty good job of protecting
(somewhat) the solder holding down the smaller adjacent components,
and/or holding those components in place if their holding solder _does_
get melted. The fact that it's transparent helps too: foil, as mentioned
by someone else in this thread, probably protects better, but you can't
see through it.

As we use it, it's on rolls, looking like thin brown "Sellotape" (UK -
Scotch tape I think US). I think the rolls shown in the Wiki article are
like it (though not sure if those ones have adhesive backing).
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

10.0 times 0.1 is hardly ever 1.0.