hp probook 640 g3 No Power No Charging

[Chandaj]

Hello,

Kindly help i have hp640 G3 the is only 20v on the jack and a few components around the charging area, but no 3v on the switch,also No service lights for charging.

Motherboard: clooney-6050a2860101-mb-a01

Regards

[aarya2611]

Re: hp probook 640 g3 No Power No Charging

Same issue plz tell

[mon2]

Re: hp probook 640 g3 No Power No Charging

@aarya2611, do you have schematics for this unit ? Please post or link them if on this forum.

If not available, start with the following:

1) locate the DCin adapter connector -> confirm the voltage on the input to the logic board.

2) review the markings on the topside of the 2 x DCIN mosfets near this DCin connector. Which parts are present ?

3) Locate near these mosfets -> the battery charger IC -> which chip is onboard your logic board ? The charger IC datasheet will help us to get an idea of how your logic board was designed. Usually the charger IC will be from Texas Instruments = 'BQ' series (former Benchmarq company).

Often, the faults are in the 2 x DCin mosfets which get damaged and need to be replaced -> this usually fixes the no power fault if the adapter is working ok.

If you have liquid damage then the fault would be somewhere else and sometimes can even cause damage to the CPU.

The mosfets can be inspected with a simple meter in resistance mode. NO POWER when checking resistance.

Start with, remove all power / no battery.

Meter in resistance mode.

Measure the resistance of each of the 2 x dcin mosfets as follows:

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

Post each measurement and the meter scale used.

Repeat for the next mosfet.

You will find 3 other mosfets that will be for the battery charging and that connects the battery to the logic board.

Also interested in the measurements of those mosfets which are high side, low side and battery mosfets.

One or more of these is leaking. The measurements will tell us which one is defective.

No power when checking the resistance values.