Asus x453ma not charging

[mon2]

Re: Asus x453ma not charging

Post the voltage of ILIM (pin 10) of charger ic with adapter attached.

Do you see the charging symbol on Windows with adapter and battery?

[Yosua]

Re: Asus x453ma not charging

Post the voltage of ILIM (pin 10) of charger ic with adapter attached.

Do you see the charging symbol on Windows with adapter and battery?

ILIM voltage = 0.68V is that normal bro?


yes..the charger symbol appears and works properly

I will measure the SMBUS CLK & DATA voltage again tomorrow bro, because tomorrow I have to go to the office early in the morning because I have to fix my boss's computer.

thank you very much in advance.. I hope you don't get bored to guide me.. once again I thank you

[mon2]

Re: Asus x453ma not charging

Yes, ILIM is ok. See attached for the conditions that must be met for the battery charging to proceed.

Post the voltages of:

1) SRN (pin 12)
2) SRP (pin 13)

on the charger IC with the adapter & battery connected.

[Yosua]

Re: Asus x453ma not charging

Yes, ILIM is ok. See attached for the conditions that must be met for the battery charging to proceed.

Post the voltages of:

1) SRN (pin 12)
2) SRP (pin 13)

on the charger IC with the adapter & battery connected.

hi bro voltage on
SRN:7.60V
SRP:7.60V
this is the condition when the battery and charger are used together.

[mon2]

Re: Asus x453ma not charging

Post the voltage of BATDRV (pin 11) when the adapter & battery are connected.

Then remove the adapter and leave only the battery connected - read the voltage again on BATDRV (pin 11).

[Yosua]

Re: Asus x453ma not charging

Post the voltage of BATDRV (pin 11) when the adapter & battery are connected.

Then remove the adapter and leave only the battery connected - read the voltage again on BATDRV (pin 11).

BATDRV = 7.45V(adapter installed condition)
BATDRV = 7.45V (adapter disconnected condition)
BATDRV = 2.65V(condition only using charger only)

[mon2]

Re: Asus x453ma not charging

Measure BATDRV with adapter removed but leave on the battery.

Then BATDRV should be about 6V + SRN voltage. Believe it is but let us confirm this detail.

[Yosua]

Re: Asus x453ma not charging

Measure BATDRV with adapter removed but leave on the battery.

Then BATDRV should be about 6V + SRN voltage. Believe it is but let us confirm this detail.

BATDRV : 13.74V mean normal?

here I see PQ8804 Voltage S, D, G all 7v is that normal?

[mon2]

Re: Asus x453ma not charging

After the above, on the backside of the logic board, locate PQ8804.

This is the HIGH side mosfet that is used to charge your battery.

1) measure and post the voltage at the GATE of this mosfet (PQ8804) when the adapter is connected. Be careful with the meter probe while measuring.

Interested also in the GATE voltage of the low side mosfet @ PQ8805. This mosfet is on the same side as the charger IC.


2) Remove all power (no battery; no adapter). Meter in resistance mode (200 ohms).

Measure and post the resistance for PQ8804:

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

The datasheet for PQ8804 & PQ8805 is attached.

3) Then repeat the same set of measurements for the LOW side mosfet @ PQ8805.

Measure and post the resistance for PQ8805:

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

[mon2]

Re: Asus x453ma not charging

BATDRV : 13.74V mean normal?

BATDRV gate voltage is normal @ 13V74 when the adapter is REMOVED. This matches what TI states in their datasheet.

To turn ON the BATDRV mosfet, the GATE voltage must be 6V higher than SRN voltage. In this case study, the BATTERY is powering the logic board so this mosfet must be turned ON.

See attached for the typical schematic that Asus has most likely cloned for your laptop.

here I see PQ8804 Voltage S, D, G all 7v is that normal?

Yes because the adapter is removed. Now only the battery pack voltage is being used to power the logic board. For this reason, each of these pins on the mosfet settle on the battery voltage.

[Yosua]

Re: Asus x453ma not charging

BATDRV gate voltage is normal @ 13V74 when the adapter is REMOVED. This matches what TI states in their datasheet.

To turn ON the BATDRV mosfet, the GATE voltage must be 6V higher than SRN voltage. In this case study, the BATTERY is powering the logic board so this mosfet must be turned ON.

See attached for the typical schematic that Asus has most likely cloned for your laptop.



Yes because the adapter is removed. Now only the battery pack voltage is being used to power the logic board. For this reason, each of these pins on the mosfet settle on the battery voltage.

PQ8804
1,2,3 =2.77V
4 =2.77V
5,6,7,8=19.54V

PQ8805
1,2,3 =GND
4 =0V
5,6,7,8=2.77V

For resistance measurement, should I connect one of the probes to ground?

[mon2]

Re: Asus x453ma not charging

Next, confirm that the ILIM pin is with the proper voltage and voltage divider resistors. You have posted ILIM already but let us confirm the details of this pin again and their local resistors.

PR8819 = 100K
PR8820 = 300K

I think that your ILIM voltage is too low which limits the current used to charge the battery. This may be the issue. It should be 0V825 and earlier you posted 0V68. Please confirm this important value again.

To fix this voltage to be 0V825, both PR8819 & PR8820 may need to be replaced. First confirm that +3v3 is truly present on the one side of PR8820. The boardview file states that ASUS used +3V for the PR8820 resistor but let us confirm this.

Next, flux and reflow both of these resistors and check again. If you do not see ILIM pin @ 0.825V then both of these parts should be replaced.

If you cannot source them locally, send me PM with your address. I believe that we can have them drop shipped to you from Arrow with our free shipping account. The parts are very inexpensive, provided that we have free shipping. If it goes well, you will have them next week by Fedex.

Also you have seen this same battery charge to 100% in another laptop ?

[mon2]

Re: Asus x453ma not charging

For resistance measurement, should I connect one of the probes to ground?

Sorry - no. Use the one meter probe to SOURCE and other meter probe to DRAIN. Then read the resistance on the meter.

Repeat for the other combinations. This will just confirm that the mosfets are not shorted or leaking.

I think there is an issue is with the ILIM resistor / voltage created by the divider circuit.

The gate voltages with adapter connected do not look correct for PQ8804 & PQ8805.

These mosfets are N-channel depletion mosfets. They will require a higher voltage than what they are passing to enable.

For example, gate of PQ8804 should be 6V higher than the ACN value on the charger IC to turn ON this mosfet.

So we should be observing about 25V on the gate of PQ8804. Since this is not the case, the charger IC could be to blame or this mosfet.

Post your resistance measurements so we can rule out a defective mosfet.

[Yosua]

Re: Asus x453ma not charging

After the above, on the backside of the logic board, locate PQ8804.

This is the HIGH side mosfet that is used to charge your battery.

1) measure and post the voltage at the GATE of this mosfet (PQ8804) when the adapter is connected. Be careful with the meter probe while measuring.

Interested also in the GATE voltage of the low side mosfet @ PQ8805. This mosfet is on the same side as the charger IC.


2) Remove all power (no battery; no adapter). Meter in resistance mode (200 ohms).

Measure and post the resistance for PQ8804:

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

The datasheet for PQ8804 & PQ8805 is attached.

3) Then repeat the same set of measurements for the LOW side mosfet @ PQ8805.

Measure and post the resistance for PQ8805:

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

I measured it using 2k mode

PQ8804
S - D = 459
S - G = 1.333
G - D = 784

PQ8805
S - D = 514
S - G = 1.462
G - D = 879

[Yosua]

Re: Asus x453ma not charging

Next, confirm that the ILIM pin is with the proper voltage and voltage divider resistors. You have posted ILIM already but let us confirm the details of this pin again and their local resistors.

PR8819 = 100K
PR8820 = 300K

I think that your ILIM voltage is too low which limits the current used to charge the battery. This may be the issue. It should be 0V825 and earlier you posted 0V68. Please confirm this important value again.

To fix this voltage to be 0V825, both PR8819 & PR8820 may need to be replaced. First confirm that +3v3 is truly present on the one side of PR8820. The boardview file states that ASUS used +3V for the PR8820 resistor but let us confirm this.

Next, flux and reflow both of these resistors and check again. If you do not see ILIM pin @ 0.825V then both of these parts should be replaced.

If you cannot source them locally, send me PM with your address. I believe that we can have them drop shipped to you from Arrow with our free shipping account. The parts are very inexpensive, provided that we have free shipping. If it goes well, you will have them next week by Fedex.

Also you have seen this same battery charge to 100% in another laptop ?

for now the voltage on Pin number 10(ILIM) = 0.33V(only uses charger and no battery)

I don't know since when this voltage dropped.

okay if it is the resistor that is the problem I will try to find it first on another mobo.

yes I'm sure this battery is normal on other motherboards.

[mon2]

Re: Asus x453ma not charging

Pin number 10(ILIM) = 0.33V

Interesting. This could be a key here. Based on this lower current limit, the charger IC could decide to turn the high & low side battery charging mosfets OFF.

The resistance of the mosfets look fine.

For comparison, on the working laptops, what is the charger IC. Is it the same model of laptop ? If yes, that is our 'golden sample'.

Proceed to check the ILIM voltage on the working laptop. It should be close to 0v8. Then also check the gate voltage on the PQ8804 & PQ8805 of the working laptop. Have this battery connected for these measurements.

I think we are getting close...

[Yosua]

Re: Asus x453ma not charging

Interesting. This could be a key here. Based on this lower current limit, the charger IC could decide to turn the high & low side battery charging mosfets OFF.

The resistance of the mosfets look fine.

For comparison, on the working laptops, what is the charger IC. Is it the same model of laptop ? If yes, that is our 'golden sample'.

Proceed to check the ILIM voltage on the working laptop. It should be close to 0v8. Then also check the gate voltage on the PQ8804 & PQ8805 of the working laptop. Have this battery connected for these measurements.

I think we are getting close...

sorry it seems too late to measure a working laptop, because the laptop has sold bro, after all the laptop is exactly the same as this, namely x453ma

does this mean damage to this ILIM?

resistance measurement on
PR8819 = .084
PR8820 = .166

I measured it using 2M mode on the avo meter

and now the voltage on the ILIM is 0.77v(unstable) when the motherboard is powered on

I'm really confused here hehehehe

[mon2]

Re: Asus x453ma not charging

Suggest to replace both of these resistors.

PR8819 = 100K 0402 1% is great but 5% will work.
PR8820 = 300K 0402 1% is great but 5% will work. TI suggested 316K but Asus appears to have selected 300K.

Can you confirm that the voltage on the OTHER side of PR8820 is 3V? Or is it 3v3?

If this voltage is lower than 3V then ILIM will also result to be lower.

Wait...0V77 is ok. Is it holding steady ? This should be ok as it is close to 0v825 (text book calculation).

Given that high side & low side mosfets are not turning on, I would suggest to replace the charger IC. From the diagnostics, the proper conditions are there for the charger to turn ON. The charging symbol is working so the charger IC has been instructed to turn ON. After this, the high side and low side mosfets should work together to 'dial up' the ideal charging voltage for this target battery pack. The gate voltage is too low for the n-channel mosfets to be turning on.

If you are ordering a replacement charger IC, will not be a bad idea to also order replacement parts for PQ8804 & PQ8805. They should not be available on Aliexpress and equivalent parts from Arrow.com.

[Yosua]

Re: Asus x453ma not charging

Suggest to replace both of these resistors.

PR8819 = 100K 0402 1% is great but 5% will work.
PR8820 = 300K 0402 1% is great but 5% will work. TI suggested 316K but Asus appears to have selected 300K.

Can you confirm that the voltage on the OTHER side of PR8820 is 3V? Or is it 3v3?

If this voltage is lower than 3V then ILIM will also result to be lower.

okay I'll try to replace these two resistors.

on the other side PR8820 is 3.32v

[mon2]

Re: Asus x453ma not charging

Please review my last message.

Summary:

1) replacing the resistors is a good idea but if 0.77V = should be ok if holding steady
2) consider to replace the charger IC since the HIDRV & LODRV voltages are too low to enable PQ8804 & PR8805 mosfets
3) not a bad idea to order replacement mosfets for PQ8804 & PQ8805 - just in case.