Toshiba L650D turns off after 6/10 seconds

[Th3_uN1Qu3]

Have this in for reballing. After reballing NB it shows video but powers down by itself after 10 seconds if the keyboard is connected, 6 seconds if it is unplugged.
It used to shut down before reballing too, when it was showing no video. It gets to BIOS if i am quick enough, it will even boot from the HDD.

It also turns off by itself with no RAM, even with no CPU. Exactly same thing in every situation, shuts down after 6 sec without keyboard, 10 sec with keyboard. Regardless of everything else. It will stay on maybe 1 second longer if i'm mashing the keys in the meantime.

I would replace KBC. In fact i would've already done that, just that i didn't have one handy and we'll have to order it. Any other ideas? I have a 100MHz digital oscilloscope to use now.

[looofy]

Re: Toshiba L650D turns off after 6/10 seconds

is'n it a thermal shutdown signal ?

[looofy]

Re: Toshiba L650D turns off after 6/10 seconds

winch platform ?

[Th3_uN1Qu3]

Re: Toshiba L650D turns off after 6/10 seconds

Board is Inventec MAS10AD. It can't be thermal, unless the thermal diode in the NB has crapped itself somehow. This board is one of the few that DOES have thermal sensing for the NB too... But i will measure and report back. I do have spare chipsets.

[looofy]

Re: Toshiba L650D turns off after 6/10 seconds

here

[looofy]

Re: Toshiba L650D turns off after 6/10 seconds

if the power was stable before the reballing then it maybe one of the legs NB_THERMD_P or NB_THERMD_N not soldered
or there is a Leakage in NB_PWRGD signal in D4505 resulting Leakage in VCC_NB_PWRGD to the kbc

[gcomputers]

Re: Toshiba L650D turns off after 6/10 seconds

Check the power button?

[Th3_uN1Qu3]

Re: Toshiba L650D turns off after 6/10 seconds

Power button is fine. It was shutting down before reballing as well, i have already mentioned that.

[looofy]

Re: Toshiba L650D turns off after 6/10 seconds

any progress ?

[kc8adu]

Re: Toshiba L650D turns off after 6/10 seconds

fan tach not being detected?

[Th3_uN1Qu3]

Re: Toshiba L650D turns off after 6/10 seconds

I have this on my backlog, there are a few more that are urgent, this one can wait.

I've found a KBC and will try swapping that if all else fails, i have yet to check the thermal sensors. I doubt it's that, as the fan starts at "off" and only spins up a little bit before the laptop shuts down. But i will check the sensors before replacing KBC.

[fddizon]

Re: Toshiba L650D turns off after 6/10 seconds

often times, shutdown is caused by shorted rails on power distribution.

check vs voltage rails

[Th3_uN1Qu3]

Re: Toshiba L650D turns off after 6/10 seconds

All power supplies ok, until it shuts down that is. Here's an update:

Fan tach signal checks out ok, thermal protect is not operating. U6001 does not receive the THRM_SHUTDWN# signal. 3.3 and 5v remain stable at all times - if it went into thermal shutdown, those rails would shut down as the output of U6001 is tied to the enable signal of the 3.3v and 5v PWM.

Replaced KBC: same behavior
Flashed BIOS: same behavior
Heated the SB a bit: same behavior

This board's stupid...

[Th3_uN1Qu3]

Re: Toshiba L650D turns off after 6/10 seconds

Replaced Southbridge today. IT'S STILL DOING IT.