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