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View Full Version : G751JY Completely Dead, No lights at all.



Reegs
01-17-2018, 06:42 PM
It started with the laptop going from AC to battery and back again when playing games.
Eventually the battery would completely discharge and not even register the DC jack.
A few days would pass and it would work again.

Now there is NOTHING. No lights at all when plugged in. Power button does nothing.

What I've done/tried:
1. Replaced battery
2. Disassembled / reassembled many times ( pulled main / bios battery and held in pwr button for 1+ minutes)
3. Tested AC - DC power plug and can confirm 19v output (OK)
4. Tested for 19v at DC mini-board going into motherboard (OK)
5. No visabable shorts or suspicious items on motherboard. (OK)

I very familiar with computer hardware and I can't figure this one out.

Because of the switching while gaming, I'm thinking about hot air reflow my GPU. It's risky and I wanted to hear thoughts or possibly other things to try first.

It's 2yrs old, so no warranty stuff.

Anyone have any thoughts?

jdfrench3
01-17-2018, 07:44 PM
A component in your battery circuit on your motherboard is most likely toast. This circuit is used to charge your battery. To test this, charge your battery using an external battery charger or replace with new fully charged battery. Once a fully charged battery is installed, the laptop should boot up. This wont fix your problem but it will confirm the battery circuit has failed. I would suggest a motherboard replacement.

Reegs
03-02-2018, 10:10 PM
A component in your battery circuit on your motherboard is most likely toast. This circuit is used to charge your battery. To test this, charge your battery using an external battery charger or replace with new fully charged battery. Once a fully charged battery is installed, the laptop should boot up. This wont fix your problem but it will confirm the battery circuit has failed. I would suggest a motherboard replacement.

Anyone familiar with the charging chips? What do they look like, where are they, have a PN for them? Anything?

I'm confident that I can desolder the old one and replace. I just need some info.

Please help,
Reegs

bindiou
11-16-2018, 10:05 PM
hi
did you check voltage at AC_BAT_SYS (after the second entry MOSFET) ?

ihave one of the laptops i am repairing with the same power issue, 19Volts rom charger not getting throught .
i could shunt it to 19volts, but then plugging a battery woould be impossible.
i already changed the mosfets (twice), the regulator, and some capacitys.
i also have the boardview.
but still not finding why the gate signal on the mosfets stay so low.
i also saw this signal is pulsing , but i dont find why .
AC_BAT_SYS stays at 3 or 4Volts.
the regulator you asked for, is a BQ735, it is located between the CPU V-CORE coils an the battery mosfets.

Reegs
11-27-2018, 09:56 PM
hi
did you check voltage at AC_BAT_SYS (after the second entry MOSFET) ?

ihave one of the laptops i am repairing with the same power issue, 19Volts rom charger not getting throught .
i could shunt it to 19volts, but then plugging a battery woould be impossible.
i already changed the mosfets (twice), the regulator, and some capacitys.
i also have the boardview.
but still not finding why the gate signal on the mosfets stay so low.
i also saw this signal is pulsing , but i dont find why .
AC_BAT_SYS stays at 3 or 4Volts.
the regulator you asked for, is a BQ735, it is located between the CPU V-CORE coils an the battery mosfets.



Would you be able to share the boardview? It would help a lot.
chris @ ftwce dot com