Asus x453ma not charging
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Re: Asus x453ma not charging
What are the voltages for SDA & SCL ?SDA and SCL voltages are normal, but ACOK is only 1.68v
ACOK, SDA and SCL are each open-drain pins. Each of these open-drain pins will have a pull-up to the +3v3 rail. So expecting that the voltage reading should be the same for all 3 of these pins.
Can you trace the circuit to locate the local pull-up for ACOK ? Once it is found, check the other side of this resistor and confirm it is +3v3. There is a chance that the PU resistor is to +1v8 but check for it with your meter.Attached Filesif you find these attachements useful please consider making a small donation to the site
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Re: Asus x453ma not charging
What are the voltages for SDA & SCL ?
ACOK, SDA and SCL are each open-drain pins. Each of these open-drain pins will have a pull-up to the +3v3 rail. So expecting that the voltage reading should be the same for all 3 of these pins.
Can you trace the circuit to locate the local pull-up for ACOK ? Once it is found, check the other side of this resistor and confirm it is +3v3. There is a chance that the PU resistor is to +1v8 but check for it with your meter.
SDA & SCL = 3.32v more or less both are almost the same.
gosh you're right, why didn't I realize that, should SDA&SCL be normal as well as ACOK should be normal right?
is there a possibility that this IC is faulty?
if ACOK has a problem, does it affect ACDRV?
because there is no problem on the path that ACDRV passes, but the voltage is still 19vComment
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Re: Asus x453ma not charging
Hello bro
1-check replace battery first (check old battery voltage also sometime battery shows percentage bt there is no voltage in battery)
2-check sda sdl data clock line path resistors
3-check voltage in mosfet (short,or leakage)Comment
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Re: Asus x453ma not charging
hi guys, thanks for taking your time to join this issue, i have checked all mosfet on dc in , and everything is normal nothing short circuit. and the battery is still goodComment
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Re: Asus x453ma not charging
See attached.
From the boardview files, pin #5 of the charger IC = AC_OK.
This is an open-drain pin so it must use an external resistor to pull-this line to the logic high level for the pin to function correctly.
This external pull-up resistor is PR8812.
1) Meter in DC volts scale (20V max is ok).
2) Red meter probe on the PR8812 (measure the side of this 1M resistor) - is it 3 volts here ?
3) Then check the OTHER side of PR8812 - what is the voltage ?
4) Finally, what is the voltage on the OTHER side of PR8813 (yellow pad) = the voltage that is @ AC_OK pin of the charger IC ?
Post each voltage reading.
Since this is an open-drain pin, the external resistors define the high voltage value. Being that you have 1v62 on AC_OK then yes the charger IC could be bad OR the external resistors are bad.
Update - capacitor PC8823 is also involved with this AC_OK signal circuit.
Remove PC8823 off the logic board if the AC_OK voltage remains low @ 1v62 since we know for sure that this rail should be close to 3V under normal conditions.
With PC8823, what is the AC_OK voltage ?Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by mon2; 11-15-2021, 06:12 AM.Comment
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Re: Asus x453ma not charging
PR8812See attached.
From the boardview files, pin #5 of the charger IC = AC_OK.
This is an open-drain pin so it must use an external resistor to pull-this line to the logic high level for the pin to function correctly.
This external pull-up resistor is PR8812.
1) Meter in DC volts scale (20V max is ok).
2) Red meter probe on the PR8812 (measure the side of this 1M resistor) - is it 3 volts here ?
3) Then check the OTHER side of PR8812 - what is the voltage ?
4) Finally, what is the voltage on the OTHER side of PR8813 (yellow pad) = the voltage that is @ AC_OK pin of the charger IC ?
Post each voltage reading.
Since this is an open-drain pin, the external resistors define the high voltage value. Being that you have 1v62 on AC_OK then yes the charger IC could be bad OR the external resistors are bad.
Update - capacitor PC8823 is also involved with this AC_OK signal circuit.
Remove PC8823 off the logic board if the AC_OK voltage remains low @ 1v62 since we know for sure that this rail should be close to 3V under normal conditions.
With PC8823, what is the AC_OK voltage ?
PIN1 = 3.31V
PIN2 = 1.65V
PR8813
PIN1 = 1.65V
PIN2 = 1.64V
I've removed the PC8823 but the voltage on PR8812 & PR8813 remains the same and there is no change brotherComment
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Re: Asus x453ma not charging
Remove the dual mosfet (EM6K1-G) to the right side = PQ8810 (6 lead). Keep a note on the pin #1 of the device to be safe. It is the mosfet that is enabled / disabled by the AC_OK signal.
Measure again the voltage on AC_OK. If still low, remove PR8813 (1K) (to isolate the AC_OK pin from the pull-up @ PR8812.
Next, confirm that PR8812 pin #2 floats to +3v. After this testing, the BQ charger must be the fault as it is pulling down AC_OK rather than allowing it to float (high impedance / HI-Z) when 'high' (aka open-collector state).Comment
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Re: Asus x453ma not charging
and this is the resistance measurement:See attached.
From the boardview files, pin #5 of the charger IC = AC_OK.
This is an open-drain pin so it must use an external resistor to pull-this line to the logic high level for the pin to function correctly.
This external pull-up resistor is PR8812.
1) Meter in DC volts scale (20V max is ok).
2) Red meter probe on the PR8812 (measure the side of this 1M resistor) - is it 3 volts here ?
3) Then check the OTHER side of PR8812 - what is the voltage ?
4) Finally, what is the voltage on the OTHER side of PR8813 (yellow pad) = the voltage that is @ AC_OK pin of the charger IC ?
Post each voltage reading.
Since this is an open-drain pin, the external resistors define the high voltage value. Being that you have 1v62 on AC_OK then yes the charger IC could be bad OR the external resistors are bad.
Update - capacitor PC8823 is also involved with this AC_OK signal circuit.
Remove PC8823 off the logic board if the AC_OK voltage remains low @ 1v62 since we know for sure that this rail should be close to 3V under normal conditions.
With PC8823, what is the AC_OK voltage ?
PR8813 = 1.001Kohm
PR8812 = 0.980 Mohm - 1.000 Mohm (unstable)Comment
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Re: Asus x453ma not charging
is it safe when this mosfet is removed and given a voltage to be measured?Remove the dual mosfet (EM6K1-G) to the right side = PQ8810 (6 lead). Keep a note on the pin #1 of the device to be safe. It is the mosfet that is enabled / disabled by the AC_OK signal.
Measure again the voltage on AC_OK. If still low, remove PR8813 (1K) (to isolate the AC_OK pin from the pull-up @ PR8812.
Next, confirm that PR8812 pin #2 floats to +3v. After this testing, the BQ charger must be the fault as it is pulling down AC_OK rather than allowing it to float (high impedance / HI-Z) when 'high' (aka open-collector state).Comment
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Re: Asus x453ma not charging
For this case it should be fine. The signal is going to the gate of the mosfet. The mosfet is n-channel so needs a positive voltage to turn on. You are removing the mosfet out of circuit.
This is to confirm if the mosfet or charger ic are pulling down this ac_ok signal line.
https://www.electronics-tutorials.ws...or/tran_7.htmlComment
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