ASUS Vivobook M7600R (M6500RC R2.0) - 19V Power Rail Not generated, AC-Detect

Hello

I have an ASUS Vivobook M7600R which I received, the laptop did work on battery but now battery is depleted and it will not charge, or laptop will not power on from adapter.

There was some sort of surge and the ISL9241H chip was burnt on the battery CSON and CSOP lines and the battery charging side was short ~10ohms.

I have replaced the damaged ISL9241H and two mosfets on the battery side that are also damaged and now the short is gone and there is now 19v powering the ISL9241H but the main 19v power rail is not being generated.

The ISL9241H appears different to others I have worked with in that the AC-Detection looks as if it happens elsewhere and passes just the AC-OK signal to the ISL9241H. The ISL is getting 19v DCIN but there is no VDD on pin 18, without a schematic for this board I am having trouble finding the fault.

Can anyone help? Thank you.

Hello!

Measure the resistance and voltage to ground on pin 8 of charger chip.

Hello matic

pin 8 of ISL9241H
voltage = 0v
resistance = 29 ohms

KenM0560 wrote:resistance = 29 ohms

This resistance is definitely too low.
Remove the charger chip from the board and remeasure the resistance to ground on pad 8 on the place of charger chip. If the resistance will increase to a high value (kΩ range or greater), the charger chip is damaged and needs to be replaced.

With the ISL chip removed pad 8 resistance is now around 2M ohms!

This is the second time i have replaced the IC first one was from a spares board and this current IC was bought brand new. Would there be anything on the board that is damaging the chip or is this from a bad batch?

Also with the chip from the spares board, when fitted i get around 500k ohms and around 215mV on pin8 of ISL chip.

If all five transistors controlled by this chip (their gates are connected to the pins 5, 7, 9, 11, 32) are fine, your replacement chips are probably bad. Of course, assuming that your have soldered the chips fine.

All of the connected mosfets look to measure ok, there is no direct short when in continuity mode measuring from S-D, S-G, D-G and resistance is in the 100k ohm range or higher. The two mosfets connected to pins 9 and 11 are measuring around 200k ohm from drain to source, is that acceptable? should it not be a higher reading?

The chip is soldered ok all pins are connected when looking closer with the microscope.

KenM0560 wrote:is that acceptable? should it not be a higher reading?

Yes, that's acceptable. The transistors seems fine.

Do you have a low resistance to ground on pin 8 of charger chip with both chips you have (the one removed from a donor board and also the other brand new one)?

Ok thanks for confirming.

With the brand new chip on pin 8, i got 0v and 29ohms

and with the chip from a donor board on pin 8, i got 215mV and between 400k - 500k ohms and slowly rising.

So the brand new chip is definitely dead.
Because we are not sure about the functionality of the chip from the donor board, you need another one.

Order another chip, preferably from another vendor.

Hi

I received a new IC from Mouser Electronics, i have fitted it to the board and still no main power rail is generated. The IC is getting 19V on pin 17.

Pin 18 and 8 measure around 215mV and 5M ohm resistance now.

Measure the voltages to ground on all pins of battery connector with the power supply + battery connected.

With Adapter and Battery connected

Battery Connector Pins
1= 0V
2= 0V
3= 3V
4= 0V
5= 0V
6= 0V
7= 0V
8= 0V

The battery is damaged and needs to be replaced.
Repeat the measurements with another battery.

The customer mentioned that the laptop did run off the battery after the surge whilst there was some charge left in it, but it was unable to be charged again.

Clean the charger chip area of the board with IPA and post a clear picture of charger chip with nearby surrounding.
The picture you attached in the firs post is not very clear.

KenM0560 wrote:ISL9241H chip

This laptop will not work without a working battery.

matic wrote:Clean the charger chip area of the board with IPA and post a clear picture of charger chip with nearby surroundings.

Sure see attached images, as mentioned previously there was damage to the CSON and CSOP lines, i repaired these with jumper wire and they are making contact with the ISL chip.

carrneiro wrote:This laptop will not work without a working battery.

Im not fully sure on the condition of the battery, just the customer said that the laptop did still work on battery but was unable to charge and work off the adapter, and when the battery depleted fully it was unusable.

Was this board spilled?
The components in your first and third picture seems to be corroded.

No liquid damage just a surge.

I have a polarizing filter on the microscope and when removing the glare it can make the components look a little bit dull, with naked eye they are fine.