MicroSoft Surface Laptop 1769 totally dead

[mferna14]

Hi all., I am working on MicroSoft Surface Laptop 1769 which does not turn on all. No liquid spill & it's clean. My initial testing was checking all the fuse & MOSFET & they all seem to be ok. Please take a look at the ISL9237HRZ battery charging chip pin 19, this does not seem right ACIN 1.1V. I have taken all the voltages on the ISL pins. Please shed a light on them, Thanks for the cooperation.
ISL9237HRZ

Pin 1 8.79V CSON
Pin 2 8.79V CSOP
Pin 3 8.79V VSYS
Pin 4 5.8V BOOT2
Pin 5 1.1V UGATE2
Pin 6 0.76V PHASE2
Pin 7 4.7V LGATE2
Pin 8 5.1V VDDP
Pin 9 4.7V LGATE1
Pin 10 0.76V PHASE1
Pin 11 0.76V UGATE1
Pin 12 5.9V BOOT1
Pin 13 1.9V ASGATE
Pin 14 12.8V CSIN
Pin 15 12.8V CSIP
Pin 16 12.8V ADP
Pin 17 12.8V DCIN
Pin 18 5.1V VDD
Pin 19 1.1V ACIN
Pin 20 0V OTG_EN_CMP_IN
Pin 21 3.2V SDA
Pin 22 3.2V SCL
Pin 23 0V PROCHOT
Pin 24 3.2V ACOK
Pin 25 0V BATGONE
Pin 26 0V OTGPG_CMP_OUT
Pin 27 0V PROG
Pin 28 1.5V COMP
Pin 29 0V AMON_BMON
Pin 30 0V PSYS
Pin 31 0.6V VBAT
Pin 32 8.79V BGATE

[mon2]

Re: MicroSoft Surface Laptop 1769 totally dead

Not sure if the schematic is the same but review the 2nd DCin mosfet = AON7405 - see attached.

With the noted gate voltage, it should be enabled.

Remove or replace it and test again.

This is from other surface schematics which appear to have the same charger IC onboard.

[mferna14]

Re: MicroSoft Surface Laptop 1769 totally dead

Yes mon2, tomorrow I will check whether the schematics I am using is the same like the shotshot you have sent me. The MOSFET which you have highlighted should be removed, tested & then maybe replaced. Do you think this is a problem???

[mferna14]

Re: MicroSoft Surface Laptop 1769 totally dead

Hi mon2 check this photo., this is the schematics for Surface 1769. I had purchased this pdf a while back. Anyway please check the photo, it's a bit different from your screen shot. In mine the ACIN in coming directly across the 150K resistor & then going to the chip. But I checked the resistor, it's fine. Pin 5 (DRAIN) on MOSFET Q63008 I get the 12v but across the resistor the voltage dropped... What could be the problem then???

[mon2]

Re: MicroSoft Surface Laptop 1769 totally dead

The mosfet on the ACIN line may be shunting this voltage to ground.

What are the voltage reading for pin # 5 of Q63005B ? This GATE voltage decides if ACIN will see the voltage on the 150k resistor or not.

Voltage of pin # 2 of Q63005A ?

[mferna14]

Re: MicroSoft Surface Laptop 1769 totally dead

What are the voltage reading for pin # 5 of Q63005B ? This GATE voltage decides if ACIN will see the voltage on the 150k resistor or not. OUT Here the voltage is 100% correct according to the Voltage divider calculator, should be 1.14 which is correct. Voltage of pin # 2 of Q63005A ? is 3.2V ??? is this correct??

[jeksona27]

Re: MicroSoft Surface Laptop 1769 totally dead

Surface laptop 1769, touchscreen not woring even in EUFI mode. screen is nor broken, what could be the cause? not driver issue