"Paul" wrote in message
...
Adam wrote:
System: ASUS N61JQ (laptop)
Host OS: Ubuntu 12.04 LTS


After a power outage yesterday, pressing the power button of
ASUS laptop does nothing. The laptop was/is connected to
an APC battery backup (surge protection only) outlet (via AC adapter).
AC adapter's green light is "on".

Any ideas?


The attachments in this thread may help.

"ASUS N61JQ won't start"
http://www.badcaps.net/forum/showthread.php?t=42461


Thanks (Guru Paul), that's such a cool website.


You need an account to access the attachments. The
mainboard schematic is for a member of the same family,
but might not be exactly the same as your mainboard.
(The circuit may use different component values for
65W versus 90W designs.)

The first MOSFET (one circled on a schematic page),
is an inrush limiter. If the AC adapter is "hot" and then

If "hot" means to the touch,
I just felt the ASUS AC adapter and
it does not even feel warm.

For comparison, I also felt my DELL AC adapter and
it feels warm (but not hot).

Both laptops are not powered "on".

So, DecadentLinuxUserNumeroWhat (haha) may be onto something.
Sorry, DecadentLinuxUserNumeroUno, I couldn't resist. :-)

Where's the best chance of getting a compatible AC adapter?
Fry's? Radio Shack? Other?


plugged into the barrel connector, a lot of current
would flow for a short period of time. Instead, the
inrush limiter gradually turns on the power, using an RC
circuit tied to the gate. And the inrush limiter
prevents the overcurrent inside the AC adapter
from getting tripped.

I don't see a fuse in that schematic. It's possible
if a fuse is present, it sits in front of a clamp diode.
If, somehow, reverse bias is applied to the barrel
of the power connector, the clamp diode starts to
conduct (protecting the motherboard). The fuse would be
there, so the clamp diode doesn't burn out. Otherwise,
the AC adapter has its own current limiting inside
the adapter, so doesn't really need a fuse at the
motherboard level.

What I learned from that thread, is "look for burned stuff" :-)
That's better than trying to decode that schematic...

Paul

I haven't disassembled the laptop yet but nothing smells burnt.