HP Zbook 15 G2 laptop won't turn off completely

[RODAKSAN]

Hi everyone, I have a HP Zbook 15 G2 with some issue, it won't turn off completely. Once you turn it off by OS or Manually, the screen goes off, but the fan goes crazy at full RPM and it don't stop until the battery is drained. It is not a OS issue, the laptop does not turn off with or without OS. May be a thermal issue?

Motherboard:LA-B381P with latest BIOS version, OS works normally, no faulty devices found on HP diags.
It has new thermal compound and clean fans.
Found no burned components on visual inspection.
Holding the power button does not work, it keeps blowing air.

Please help, I already have the schematics and the tools to do a rework.

Best regards

[mon2]

Re: HP Zbook 15 G2 laptop won't turn off completely

Power down and remove the wifi module and test again.

[RODAKSAN]

Re: HP Zbook 15 G2 laptop won't turn off completely

Thank you mon2 ,
I removed the wifi module, same issue; once you plugged in the Battery charger, it starts to blow air, if you turn it on, the fan works normally until you turn off the book and then goes crazy again

[mon2]

Re: HP Zbook 15 G2 laptop won't turn off completely

Do you get the crazy fan spin if running from battery only ?

[RODAKSAN]

Re: HP Zbook 15 G2 laptop won't turn off completely

same issue with both only battery powered and battery charger powered (original 120W)

[mon2]

Re: HP Zbook 15 G2 laptop won't turn off completely

What is the voltage of pin # 2 (TACH_FAN_IN) on JFAN1 connector when the fan is normal speed ?

What is the voltage of this pin when the fan is in crazy spin mode ?

The fan speed is decided by the SMC @ U17. This component sends out the stream (pin 121) of the PWM signal to speed up or slow down the fan.

[RODAKSAN]

Re: HP Zbook 15 G2 laptop won't turn off completely

ACH_FAN_IN 3.3v, zbook turned on with no fan movement, it starts to spin seconds later
ACH_FAN_IN 1.72v, in normal speed
ACH_FAN_IN 1.72v, fan at full speed (zbook powered off)

[mcplslg123]

Re: HP Zbook 15 G2 laptop won't turn off completely

This happens 'coz your VS lines are not not switched off even after turning off from windows. Check your dc-dc converter for 3V/5V VS .(U45/U46)

[RODAKSAN]

Re: HP Zbook 15 G2 laptop won't turn off completely

Thank you mcplslg123!! I found u45 burned, now I'm looking for a replacement. Once u45 replaced, I will post the result.
Best Regards

[RODAKSAN]

Re: HP Zbook 15 G2 laptop won't turn off completely

Success!! I replaced the U45, brand new part from china (take so long time to get here :p) but the laptop works again normally. Thank you all who helped me, specially to mcplslg123