Panasonic toughbook cf-h2 Mk1 no power, 3.3v-5v present but no 3v on bios chip

[eukal]

Hello, i have a Panasonic Toughbook Cf-H2 Mk1 that won't power on. The battery charge without problem but no response from the laptop when i press the power button.
I have disassemble and unpluged the cmos battery, same no power on on battery with and whitout the adapter, and only adapter
I have check the voltage i have the main power rail ( +-16v normal for toughbook it's not 19v). I have on the coil after power management chip 3.3v and 5v.
I have check the 3.3v on the power button ribbon cable attach to the motherboard and the voltage go to 0v when i press the button. So no problem on the button i think.
After that i have check the voltage on the bios chip and no voltage at all (only 10mv on 3,5,7 but same with ac adapter remove)
For what i know the 3.3v is getting by bios chip from the 3.3v always, maybe with a resistor between but i have no schematics to trace the voltage.
If anyone have an idee to help me.
Thanks.

[Sephir0th]

Re: Panasonic toughbook cf-h2 Mk1 no power, 3.3v-5v present but no 3v on bios chip

Most often the 3.3V for the BIOS chip comes from a load-switch which needs its own enable later in the sequence. So the board might by simply stuck even earlier in the sequence.
Detailed inspection of all secondary power rails necessary,.voltages and resistances. Also a schematics would clarify this instantly. Dunno whether there is something available.

[eukal]

Re: Panasonic toughbook cf-h2 Mk1 no power, 3.3v-5v present but no 3v on bios chip

Most often the 3.3V for the BIOS chip comes from a load-switch which needs its own enable later in the sequence. So the board might by simply stuck even earlier in the sequence.
Detailed inspection of all secondary power rails necessary,.voltages and resistances. Also a schematics would clarify this instantly. Dunno whether there is something available.

Ok thanks, in my mind the bios received the 3.3v directly. I have check with thermal cam, no hot spot. And whitout schematics hard to trace the volatge and check the resistance. I have ask the schematics in the apropriate section.

[eukal]

Re: Panasonic toughbook cf-h2 Mk1 no power, 3.3v-5v present but no 3v on bios chip

So after more research i apply 1v 0.3a on the bios 3v leg and found the smsc chip model mec1609 goes hot on thermal cam. So i think this chip is dead but i have no tools to program a new one so i stop now and start to search a motherboard to repair the laptop. Thanks anyway.