Toshiba A300 turns off after 10 secs

[rmps]

Hi guys..

This notebook turns off after 10 seconds. Even on bios... I´ve tried with battery only and power only and even with battery + power. Same results.

Initially this notebook didnt power on because the TI BQ24721C was shorted. So i´ve bought one and changed it. Now the notebook powers up fine, i can access the bios but it turns itself off after 10 seconds no matter what i do...

Already replaced the NEC/TOKIN chip too...

Any ideas?

Thanks in advance

[spleenharvester]

Re: Toshiba A300 turns off after 10 secs

Remove RAM and power it. Does it still power off after 10 seconds?

[rmps]

Re: Toshiba A300 turns off after 10 secs

yes it does mate :/

[janpol10]

Re: Toshiba A300 turns off after 10 secs

You have to replace the capacitor (NEC TOKIN) with the same value Or another options is the modification process using 4 tantalum capacitor (330uf atleast 2.5 volts).

[spleenharvester]

Re: Toshiba A300 turns off after 10 secs

That's really peculiar. And almost certainly not an NEC/Tokin problem (I have powered Tokin repaired L300 boards up with shorts across the caps and no caps at all before and not a single one of them powered off). Maybe a thermal shutdown?

Personally, I'd go through all the S0 power state voltages (5V run, 3V run etc) and measure them from power on time until power off time. Maybe something is gradually dropping below a threshold?

[fddizon]

Re: Toshiba A300 turns off after 10 secs

Remove processor. Test all coils to ground using ohmmeter. If u find a short in one of them, you know what to do

[whaldsz]

Re: Toshiba A300 turns off after 10 secs

You may try to reflash the bios.

[spleenharvester]

Re: Toshiba A300 turns off after 10 secs

Actually, come to think of it, my test L300 board does this if no processor is present. I know it POSTs but have you tried a different one?

[rmps]

Re: Toshiba A300 turns off after 10 secs

Actually, come to think of it, my test L300 board does this if no processor is present. I know it POSTs but have you tried a different one?

I've tought about it too but i dont have another one to test.... :/
I'm going to test the coils later like the other member said. Then i'll post results.

[spleenharvester]

Re: Toshiba A300 turns off after 10 secs

Whereabouts are you based? If you're in the UK I can chuck a Celeron 900 in the post for you to try.

[rmps]

Re: Toshiba A300 turns off after 10 secs

Ok, so..

Tested all coils for shorts. Nothing shorted!

Tested with another CPU. Same problem!

I´m out of ideas....

[dycc]

Re: Toshiba A300 turns off after 10 secs

probably something that heats

[robrock1]

Re: Toshiba A300 turns off after 10 secs

check if the cooler really touches the cpu, maybe there is some small gap between? Had similar problem before, i had to bent the cooler and screw it back very tightly.

[dj_ricoh]

Re: Toshiba A300 turns off after 10 secs

Ok, so..

Tested all coils for shorts.

What is a good value and a bad value for a coil?

[robrock1]

Re: Toshiba A300 turns off after 10 secs

a coil should generally be low ohms, if it burns resistance will go up. but it will need a lot of power so you will see it from the outside.

[jtamad44]

Re: Toshiba A300 turns off after 10 secs

to make it sure, remove coil and measure the value, if the value is ok, then trace backward or forward reading.

[infosquadsn]

Re: Toshiba A300 turns off after 10 secs

What is the mainboard model ?

Could be a overheat protection circuit issue or even a BGA problem on the southbridge.


Sorry my poor english and good luck