Hi!
I'm dealing with 2 Toshiba sat M40-307, with same symptom : constant reboot after 15 to 20s, with no display.
GPU reflowed with no result.

Did anyone experience the same situation or have any clue ?

Platform : 6050A2028701-MB-A03

Should appreciate any help.

Further to my post, wish to add :
Bios is phoenix.
Post card reading jumps directly from 00 to 86 and back cycle.
Current reading rises to 1.1V and down to 0V in a cycle of 6 times then lap shuts down.

p.s help as where to dig ?

Thanks

Hi members,

No one encountered the same problem !!!

Quite surprised not to get any advice as where to dig since my first post, 10 days ago !

So did not have such a problem if people did not respond

But they might have faced similar situation with other Toshiba or other brands, so I need a guideline as where to dig ?

P.S read 1.1A and down to 0A

The problem is well known. NB.
Reflow helps randomly. So you have to replace the chip.

Hi Panasonic! nice to hear from you.
I'll try a 2nd reflow and will post back. Unfortunately I'm not yet equipped with BGA machine.

You can create it by yourself, it not that hard .
First of all you need a good heating "bottom".
It should be a square surface controlled by some regulator and
wide enough to fit a mobo.
You might use an electric grill, a stove, an oven, whatever to heat up
the bottom side of a mobo following two conditions: the heating process must be
gradual by time and even by square.
To get the graduality you can use PID like this
http://www.aliexpress.com/item/Dual-Dig ... 07874.html
To obtain the evenness you can use a temper glass from an electric bake oven.
The glass is also a good surface to put a mobo on using small teflon or even metal stands.
For upper heating device you can use a heat air gun.
Also you might need a pair of multimeters with thermocouples to measure bottom side and
the area near the soldering chip. Or just one for calibrating of PID target temperature to achieve
about 170C on the bottom side and for further additional control of upper heating.
The upper works you can do manually (visually) checking the melting temperature.

Do not forget that the reflow is just a diagnostic measure not a repair.

Thank you for the idea, which I guess is not difficult to achieve.
I can use for upper heating my "yaxun_863D" BGA infra-red station, which I bought some months ago and didn't yet get good control of it.