MOSFET no voltage at gate Quanta G7HA DAG7HAMB8EO

[irfan karatela]

I'm working on a HP Pavilion Laptop Model 15-eh1508sa that is missing 19v. I've looked at the schematics and want to know what conditions the ISL9238C checks before it enables the gate for MOSFETs PQ8200 and PQ8201,

I havent found any shorts on the board.

I get 19v at +PRWSRC but around 1.7v at the Drain of PQ8201(+vin)

On Page 82 of the attachment. Link to schematic - https://www.badcaps.net/forum/troubl...g7hamb8e0-g7ha

[mon2]

See here:

https://www.badcaps.net/forum/troubl...arging-circuit

On charger ICs, often it is the ACDET pin which must be around 2v6 or higher to denote that a valid charger is attached.

[semajnoerrac]

I'm working on a HP Pavilion Laptop Model 15-eh1508sa that is missing 19v. I've looked at the schematics and want to know what conditions the ISL9238C checks before it enables the gate for MOSFETs PQ8200 and PQ8201,

I havent found any shorts on the board.

I get 19v at +PRWSRC but around 1.7v at the Drain of PQ8201(+vin)

On Page 82 of the attachment.

check BQ chip

[pc_okay]

Hello,

I think you are facing a more complex system, that you usally see.
This is a buck/boost converter with double mofset (connected to the big Coil and to the ground).

So during normal functionning, the charging IC pulse voltage to the gate of the dual mofset to lower the voltage. (with the help of the big coil and caps and ground...)
This is a typical system on USB-C charging laptop.
You can't see those pulses with a multimeter, you need and oscilloscope for that.


But don't worry you don't actually need an oscilloscope for now!

First check voltage on +VIN rail with adapter only, you may find battery voltage approximatively. (without the battery plugged).