HP Omen 17 - cb1001na GPC72 LA-J672P

[tommy97]

Hi,

we've got a problem with laptop HP Omen 17 - cb1001na GPC72 LA-J672P, laptop does blue-screen every minute or two when on full load, sometimes even while idle. Ram, SSD, cooling everything been tested, we've got 2 other boards of Aliexpress however they always come faulty (One no power, 2nd switch off within a second). I don't have much experience in fixing this kind of problems, so I'm looking for tips.

[mon2]

Start with the one with no power.

1) be sure you are using a compatible power supply - the center adapter ID pin from the original is required. This analog voltage is used to identify the power rating of the adapter. If it is not present, the logic board may not power up.

2) The no power may be due to a faulty mosfet. Best to start with the charger IC and measure the main power rail's resistance to ground. You are checking the resistance to check if there is a shorted component on this critical power rail. With no power, meter in resistance mode (not diode mode) -> measure the resistance to ground.

Would you have a schematic? If not, need pictures of your board.

The approach is to locate the DCin power connector -> nearby will be 2 x DCin mosfets (8 pins; 4 on each side; black body). Usually the fault is here. Nearby will be the charger IC (BQ series by Texas Instruments is the most common) and this IC drives the DCin mosfets. The mosfets are like solid state relays that are required to turn ON / OFF to power the board.

We are after the resistance to ground first and later, power the board and measure the voltage to ground of each pin on the DCin mosfets.

Interested in the

Source (1-2-3) ; pin 1 pin voltage to ground
gate (4)
Drain

If the GATE pin is ~25 volts, then this mosfet will turn ON, else will be OFF.

Repeat for the 2nd DCin mosfet.