Technical Support LENOVO NM-B453 BATTERY NOT CHARGING

[Ipart]

Hi, laptop working on AC adapter, also working on battery. But when battery and ac adapter are connected, battery in not charging and laptop work on battery not on ac adapter. Replaced battery and bq24780s. What could be the problem?

 

[Ahmad Safari]

Hello
We have two MOSFETs for battery charging
They may be injured.

 

[Ipart]

Hello
We have two MOSFETs for battery charging
They may be injured.

replaced but not change. I've measured a few voltages, can you check it?

Only AC Adapter	AC ADAPTER+BATTERY
PJ301- 19,5V	7V
PL302- 0,85V	7V
ACOK- 3,3V	3,3V
ACDET- 2,7V	2,7V
REGN-6V	6V
HIDRV- 0,82V	0V
LODRV-0,82V	6,9V
BATDRV-0,85V	13,2V

HIDRV maybe problem? but there is new PU301 and new mosfets(PQ315 AND PQ316). Resistance between PU301 pin26 and PQ315 PIN4 is 0ohm. PQ301 PIN5 -7V
Any idea?

 

[Ahmad Safari]

There is a problem with the HIDRV pin.

The problem can be from ICs or MOSFETs.

Sometimes the pins are not soldered well and have to be re-soldered with solder.

Check the health of the MOSFET with a diode test.
Test on the motherboard: source to drain should be like a diode.
The gate should not be related to the source and the drain, or the value should be very high.

 

[Ipart]

There is a problem with the HIDRV pin.

The problem can be from ICs or MOSFETs.

Sometimes the pins are not soldered well and have to be re-soldered with solder.

Check the health of the MOSFET with a diode test.
Test on the motherboard: source to drain should be like a diode.
The gate should not be related to the source and the drain, or the value should be very high.

I checked it again and all mofets are ok. I also checked CMSRC and ACDRV. When only the charger is connected CMSRC 19.9V and ACDRV 25.9V . but if a battery and charger are connected CMSRC and ACDRV =0V

 

[Ahmad Safari]

These values indicate that the laptop with the battery does not recognize the charger.
Now you have the same values with the battery alone.
Replace the battery and adapter.
IC charging and SIO microcontroller may also be the cause of this problem.



Unrelated note:
Some of the new laptops have a battery detect screw or a battery detect micro switch.