HP zbook 15u g3, doesn't work with AC

[mastsrl]

Hello,
i have a curious issue with a HP zbook 15u g3 (motherboard 6050A2822301-MB-A01):
It doesn't work with the AC adapter plugged AT ALL, it doesn't charge the battery either.
When you plug the charger, the notebook "turns on"(power led, no video) for ~2s and turns off.

If i charge the battery externally, the notebook works perfect, but it doesn't detects the AC adapter at all(nor charges it, it also don't get no adapter warning).

It's not a blown pass mosfet either, because without battery, it turns on for 2s and i also have 19V on the internal power rail, since i can't find any schematic for this motherboard maybe someone had any ideas.

I'm thinking that the AC adapter identification circuitry must be fried(as some HP notebooks won't turn on without a specific identified AC charger, nor charge the battery), but without schematics i'm not sure how it reads it in this model

[Techtiger]

Re: HP zbook 15u g3, doesn't work with AC

Find out what is Charging IC ID BQXXX ect & find out pin ACOK ACIN from schematic or PDF then The voltage of those pins what is the the Voltage on the 1st 2Fets

[mastsrl]

Re: HP zbook 15u g3, doesn't work with AC

Find out what is Charging IC ID BQXXX ect & find out pin ACOK ACIN from schematic or PDF then The voltage of those pins what is the the Voltage on the 1st 2Fets

I did check with the datasheet and everything seems ok:

ACDET is at 2.77V, ACOK is at 3.33V

ACDRV is at 25V and both input mosfets are active and passing the 19V to the internal bus

yet it doesn't turn on

[Techtiger]

Re: HP zbook 15u g3, doesn't work with AC

What is your Charging IC & SIO ?

[mastsrl]

Re: HP zbook 15u g3, doesn't work with AC

What is your Charging IC & SIO ?

The controller is a TI bq24780s, SIO is nuvoton npce586ha0mx

More testing i did and reverse engineering to find the components and some oddities, did a table with AC, BAT and BAT+AC:

AC Only:
As i stated in the previous post: internal rail is at 19V:
ACDRV: 26V
BATDRV: 12V
VCC: 19,26V
ACOK: 3.33V
BATT(battery terminals): 11,9
PHASE: 20,78 (this is an oddity, the phase pin has 20.78 DC, but the battery connector has only 11,9V)
i also checked extra pins:
REGN: 5.96v
BATPRES_: 0v

Battery only:
ACDRV: 0
BATDRV: 17
VCC: 10,63
ACOK: 0
BATT(battery terminals): 11,59 (battery is fully charged)
PHASE: 20,78 (this is an oddity, the phase pin has 20.78 DC, but the battery connector has only 11,9V)
REGN: 0v
BATPRES_: 0v

Batt+AC:
ACDRV: 25,7
BATDRV: 12.75
VCC: 19
ACOK: 3,33
BATT(battery terminals): 12,58
PHASE: 16,42
REGN: 5,9v
BATPRES_: 0v

both charging FETs are getting warm, but the notebook doesn't show charge nor battery detected, i haven't checked PWM waveform yet, but it does seems like hte BQ is indeed charging the battery

[mastsrl]

Re: HP zbook 15u g3, doesn't work with AC

any idea?, i haven't been able to solve this problem yet

[mcplslg123]

Re: HP zbook 15u g3, doesn't work with AC

Check your battery discharge fet . Its likely shorted.

[mastsrl]

Re: HP zbook 15u g3, doesn't work with AC

Check your battery discharge fet . Its likely shorted.

if the battery discharge fet is shorted, then it wouldn't work with battery(or battery would overheat and last very little or blow the fet), yet it is working normally on battery and i've not noticed any fet heating up on batt.

i will recheck for shorts but i don't think i found any

[mcplslg123]

Re: HP zbook 15u g3, doesn't work with AC

Why it wont work from battery if discharge fet is shorted?? IF the fet is shorted, battery current will directly flow from drain to source of the mosfet and power the whole mb.

[mastsrl]

Re: HP zbook 15u g3, doesn't work with AC

Why it wont work from battery if discharge fet is shorted?? IF the fet is shorted, battery current will directly flow from drain to source of the mosfet and power the whole mb.

ah sorry i answered without the actual datasheet in front of me and the discharge fet you mention is the "battery drive" FET driven by BATDRV, since you said discharge i thought it was the low side drive FET(LODRV).

i will check that FET today