Asus X554LJ , mb X555LD : cannot start after battery removed

[Caimano]

MB X555LD Ver 3.3 with intel i5 5200U and graphic processor
original BIOS X555LJ (331 on the sticker) (207 on the bios screenshot)

received the laptop with damaged screen and sticky keyboard. Probable liquid damage (coffee ?) which has been partially cleaned, but still present in some small areas of the top pcb (as well as the keyboard).
The MB can work perfectly for days from battery and adapter, loads windows without any problem, charges battery. But unfortunately after the battery is removed and reinstalled it's unable to start. It takes a lot of tries, resets, adapter and battery insertions and removals to get it back to work. At this point the le laptop works and restarts without problems until battery is removed and problem reappears.
MB has been perfectly cleaned, EEPROM flashed with new version and also using ezflash from bios while it was working. same problem. Checked resistence and voltages compared with working MB : they are ok.

This is what happens when it does not work.
Inserting AC adapter : 3,3V and 5V are present. The orange charging led is lit even if no battery is present . +5VSUS present. 5VSUS_ON =3,28V. +3VSUS as well as 3VSUS_ON, as well as 1,05V starts, but immediately disappears ar start or at reset. No sign of start for other voltages.
From battery : 3,3V and 5V are present. No led is on. +5VSUS present. 5VSUS_ON =3,28V. +3VSUS as well as 3VSUS_ON, as well as 1,05V are present. No sign of start for other voltages.

Tried 3 different batteries all with 3,3V LDO_3.3V present. During start 3,3V are present on SMB pins.
Tried also resetting many times shorting to ground RTC_RST# and SRTC_RST#onJRST2201 and JRST2202. Pressing start button for 8 seconds actually resets, but start sequence does not complete.

I could not find a sequence that makes the mb working again, but afetr many resets and test it eventually works and from there on it keeps working and restarting until the battery is removed and the problem is back.

Any help or suggestions? Should I change the EC chip?
Thanks in advance

[mon2]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

I would wait on the feedback on the EC chip replacement for now.

1) Confirm the battery connector is solid. Are you using the recommended power adpater for this unit ?

2) If you remove the battery and use only the external power adapter - is the logic board able to power up normally everytime ? If not, this needs to be reviewed.

3) Remove the battery. Power up with the external adapter only - the logic board will show that the battery is connected ? It should not if the battery is disconnected.

4) With the battery charged up enough to power the logic board, is the logic board able to boot up or this is the flaky (pastry?) part of the operation ?

5) Any chance you have schematics for this ASUS ? If not, where and what is the charger IC on the boardview file ? Have the BV in my database.

Suspects are:

Battery I2C interconnect.
Current sense circuit for the battery.
Each mosfet mated with the charger IC including the battery mosfet.

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

I attach my original bin file and the boardview file closest to my MB rev3.1 instead of 3.3

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

I would wait on the feedback on the EC chip replacement for now.

1) Confirm the battery connector is solid. Are you using the recommended power adpater for this unit ?

2) If you remove the battery and use only the external power adapter - is the logic board able to power up normally everytime ? If not, this needs to be reviewed.

3) Remove the battery. Power up with the external adapter only - the logic board will show that the battery is connected ? It should not if the battery is disconnected.

4) With the battery charged up enough to power the logic board, is the logic board able to boot up or this is the flaky (pastry?) part of the operation ?

5) Any chance you have schematics for this ASUS ? If not, where and what is the charger IC on the boardview file ? Have the BV in my database.

Suspects are:

Battery I2C interconnect.
Current sense circuit for the battery.
Each mosfet mated with the charger IC including the battery mosfet.

Thanks Mon2 for your prompt reply!
Here are my comments :
1) yes, it's the original adapter. I will solder battery contacts and let you know
2) laptop does not power up normally with adapter only. I never tried when working if it powers up leaving the adapter and removing the battery. If I succeed in having it working again I will try this scenario.
3) As I said if I remove the battery and plug the adapter the board lights the orange recharge led, which looks strange, I agree
4) When laptop is working it starts and works fine from battery without adapter
5)I could not find any schematics, but I have repair guide and boardview of a similar revision. Charger IC is HPA02196RGRR

Does this help you in finding the problem?

[mon2]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

Suggest to remove all power. Meter in resistance mode (2k scale is ok).

Check the resistance for:

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

of each mosfet linked to the charger IC. Which charger IC is on your board ?

Using the charger IC markings, we should be able to locate a similar schematic for this review.

Likely there are 2 mosfets between the external adapter and the charger IC -> then HIGH & LOW side mosfets for the battery charging + battery mosfet to allow for the logic board to power off the battery.

Each mosfet needs to be measured for a low resistance check = defective mosfet.

Post your readings.

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

Resoldering the battery connector did not solve the problem.

The charger chip is bq24735 or HPA02196RGRR (datasheet attached).
Tomorrow I will perform the resistance measurements on the 5 mosfets you indicated.
For the moment I can already tell you the voltages between them whith adapter only:

Adapter--19,5V--mosfet1--19,5V--mosfet2----19,5V----mosfet3--12,75V--

19,5v---Hmosfet---12,75V---Lmosfet---0V

The charger ic outputs 12,75V when battery is not connected is and this is true also on another working board I have, And this could probably explain why the orange led is lit even when battery is disconnected.
I will let you know the findings.

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

Here are the readings (6Kohm scale) :
mosfet1 (1st near adapter) : all out of scale in both polarities
mosfet2 (2st near adapter) : all out of scale in both polarities
mosfet3 (battery side) : all out of scale in both polarities
Hmosfet (charging mosfet high side): out of scale in both polarities between D-S and G-D; between G-S 4,68Kohm in one polarity and out of scale in the other
Lmosfet (charging mosfet low side): out of scale in both polarities between D-S and G-D; between G-S 4,68Kohm in one polarity and out of scale in the other

I also checked the 5 mosfets in diode mode and they look fine to me (I can correctly read the internal diode in each one of them).

These are the voltage readings :
ADAPTER ONLY :
Adapter--19,5V--mosfet1--19,5V--mosfet2----19,5V----mosfet3--12,75V--

19,5v---Hmosfet---12,75V---Lmosfet---0V

BATTERY ONLY :
Adapter--0V--mosfet1--0V--mosfet2----7,94V----mosfet3--7,94V--

7,94v---Hmosfet---7,94V---Lmosfet---0V

ADAPTER + BATTERY :
Adapter--19,5V--mosfet1--19,5V--mosfet2----19,5V----mosfet3--7,94V--

19,5v---Hmosfet---7,94V---Lmosfet---0V

That's what I would expect from them.

I would geuss that I2C (SMB) battery interconnect work fine because when it was working I could read all the battery parameters with HWMonitor utility, and even when it does not start the battery charges fine (orange led) until fully charged (white led).
Same for current sense circuit.

The thing that puzzles me and I cannot explain is the different behaviour of +3VSUS and 3VSUS_ON with or without adapter :
with adapter : +3VSUS and 3VSUS_ON go high for a moment then go back to 0V
with battery : they go to 3,3V and stay there (3VSUS_PWRGD =2,98V)

Anything to check in the RTC circuit which is powered by the 3,3 LDO voltage from the battery?

[mon2]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

This thread implies it may be bios related:

https://www.badcaps.net/forum/printthread.php?t=84589

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

I tried flashing EEPROM with programmer with a more recent version (507) after cleaning ME : same problem.
When it was working I successfully used ezflash to load new version 603. but even with this latest version the laptop stopped working when I removed the battery.
Today I tried 3 different bios versions (X555LJ 207, 570, 603) using a chip from another board, but same problem:
Running on battery : starting sequence stops after turning on +3VSUS, +5VSUS, +1,05VSUS
with adapter (with or without battery) : starting sequence stops after turning on +3VSUS, +5VSUS, +1,05VSUS, but then only +5VSUS stays on .

If there will be no suggestions from forum, next step will be replacing the ec chip.

[Caimano]

Re: Asus X554LJ , mb X555LD : cannot start after battery removed

I finally found a workaround to make the mobo work again : I installed a 3V coin battery between LDO_V3.3 and GND. With it the board starts every time without problem.
I Don't understand why it does not work with the battery supplying the 3V (I tried 3 different batteries all having 3V on pin 5 ), but I already lost too much time troubleshooting this problem to investigate further.
In case you are having problems with X555LD not starting , you might give it a try.