Asus FX504 not charging battery

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Re: Asus FX504 not charging battery

Without anything connected it's about 35k ohms. With battery connected - 0 ohms

[mon2]

Re: Asus FX504 not charging battery

The battery is defective as this pin should not be 0 ohms when connected to the logic board.

This P_CLK pin is a signal that is used for communication with the logic board to share the battery properties, charge level, etc. Without this signal, the communication cannot proceed.

Suggest to source another battery and test again.

Do update this thread.

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Re: Asus FX504 not charging battery

Thanks for your help. I will order a new battery and will let you know

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Re: Asus FX504 not charging battery

So I got a new original Asus battery and.... it's the same issue. Without battery laptop works on AC charger, but when I plug it in, it does not charge and works on the battery power.

But when I use some random 19V power supply, it magically starts charging. But only after a reboot. When I unplug and plug it again, then it starts using battery again.

With original PS it does not work even after a reboot

[mon2]

Re: Asus FX504 not charging battery

What is the voltage of P_CLK with the new battery ?

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Re: Asus FX504 not charging battery

About 3,25 V on both clk and data

[mon2]

Re: Asus FX504 not charging battery

That is an improvement over the 0v for past P_CLK value.

Remove PQ23 (battery mosfet) and test again.

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Re: Asus FX504 not charging battery

Now the laptop thinks it's charging all the time. When I unplug and replug the charger it does not drain the battery anymore. It does not charge.

[mon2]

Re: Asus FX504 not charging battery

If you leave this battery mosfet off the board and continue to leave in the 'charge mode' with the power adapter, does the battery pack actually charge ?

Allow it to remain in this state for 30mins - 1 hour and check the voltage again on the battery pack - without the adapter.

What is the voltage of MBATV ?

Check if the attached thermal sensing parts are stuffed on your logic board.

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Re: Asus FX504 not charging battery

I don't think it is charging, voltage of battery is still the same - 11,52 V. With adapter or without.
MBATV is 2,15 V.

I will check the sensor tommorow.

[mon2]

Re: Asus FX504 not charging battery

Ok. When you are back at it...

1) check the voltages on ILIM (pin # 21) and ACDET (pin # 6) with the battery and charger attached. Still leave the battery mosfet (PQ23) off the logic board.

2) remove all power -> meter in resistance mode -> check the resistance values of the resistors @ ILIM (pin # 21). Do the resistor values match the schematic values ?

3) Does the BAT+ (battery connector voltage) increase when you apply the AC power adapter ? If not, the high side (PQ26) and low side (PQ27) mosfets need to be reviewed again.

With no power -> meter in resistance mode -> check the resistance across each mosfet pins:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate(4)
gate (4) & drain (5-6-7-8)

Post the measurements and the scale used on your meter for these checks.

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Re: Asus FX504 not charging battery

This board does not have PU38 and its components fitted.

ACDET is 2,66 V, ILIM = 0,71 V. without power it has resistance of 11,9k ohms.

PR225 should be 45k, measures 35k (on the board, so it looks fine), PR226 measures 12k.

Bat+ voltage does not increase.

PQ26:
S-D starts at 50k, goes up for 2M.
S-G 9,3k
G-D 3,75k

PQ27:
S-D starts at 15k, goes up for 150k
S-G 200k
G-D 200k

BTW thanks for your help. You're amazing!

[mon2]

Re: Asus FX504 not charging battery

PQ26 mosfet resistance looks low.

What is the voltage of BATPRES# pin 15 ?

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Re: Asus FX504 not charging battery

BATPRES is 0V with or without the battery.

What is purpose of the PQ23 (removed) anyway?

I am not sure anymore, but I think I replaced the charging FETs from some other MB I had lying around. Now it has AON7410, it should have AON7506 according to schematic, but they looked simmilar enough for test. I can order new ones, but I doubt it will help

EDIT: yes I have replaced them, it's on first page, lol.

[mon2]

Re: Asus FX504 not charging battery

BATPRES# will be ok with 0v but see attached.

Locate the small mosfet on BAT_PRS# line.

Do you have this circuit stuffed on your logic board ?

WITHOUT the battery, the mosfet (PQ88) should be OPEN. If PQ88 is open, PR531 will pull-up this line to ~3v. Review if you have PR531 onboard and also measure the +3VPCU rail. It should be present.


1) Post the voltages on each pin of the HIGH and also the LOW side charging mosfets (PQ26 & PQ27).

Source (1-2-3)
Gate (4)
Drain (5-6-7-8)

Also measure the voltage @ pin # 4 (GATE) of the missing mosfet @ PQ23 (battery mosfet).


2) Also need the voltage readings of the pins # 19 & 20 on the charger IC.

Voltage on ACOK pin # 5 of the charger IC ?
Voltage on ACDET pin # 6 of the charger IC ?

Do connect the battery during the above testing.


3) We want to leave out the battery mosfet (PQ23) till we can confirm the charger is working properly.

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Re: Asus FX504 not charging battery

Mosfet and its components are not installed. +3VPCU - 3,3 V

Battery installed, ASUS charger plugged in:

PQ26:
S - 11,44 V (same as battery voltage)
D - 19,34 V
G - 11,44V

PQ27:
S - GND
D - 11,44 V
G - 0 V

PQ23:
G - 11,44 V


PU15:
SRN - 11,44 V
SRP - 11,44 V
ACOK - 3,25 V
ACDET - 2,67 V

BTW where did you get the schematic? I only have boardview

[mon2]

Re: Asus FX504 not charging battery

Have you replaced mosfet PQ22 yet ? If not, do so.

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Re: Asus FX504 not charging battery

I have not replace it since the laptop worked on adapter just fine. But I have ordered 3 pieces to replace PQ21-23 and also 2 new charging FETs for PQ26 and PQ27. It should arrive next week, I'll let you know about the result.

EDIT: sorry about double post, internet issues...

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Re: Asus FX504 not charging battery

I have replaced both main and both charging FETs and again, no charge.

When I measure the PQ22 I only have 10,9V on VA line. That's too low, right?

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Re: Asus FX504 not charging battery

I have no idea what happend, but after replacing the PQ21 and PQ22 the motherboard is dead again. I get 20V on VA+, but nothing on the VA. I put back original FETs, but nothing has changed.

When I plug in the battery it powers on normally, but still doesn't charge and now it doesn't run on AC at all.

I give up on battery charging, I just want the laptop to work on AC again as a desktop replacement. Is it bad idea to short VA and VA+ ?