Lenovo Yoga 500-14IBD LT41 Wistron 14217-1

Hi,

this laptop have missing a voltage from power up sequence.

The 1D05V_M step is present only in in page 99 and 100 in schematic, but seems that there are no components connected to it.

It is the seven step in the power up sequence, and the PCH_RSMRST# is 2 step after it.

PCH_RSMRST# are reseting the PCH, (PCH_RSMRST# is 0,0v) so nothing functions after that.

Probably is a bug on the schematic.

The PCH_RSMRST# diode reading is .470 so no short-circuit in it.

There are some activity on bios, but a few pulses, on pin 1, and also on pin 5. (Pulses at pin 5 are below 2 volts)

This low voltage at pin 5 makes me think that problem is a pch/cpu related issue.

Can someone point me a in the right direction to solve the problem?

Thanks.

Check PU4801 1D05V_PWR.

No output from PU4801, activating signal, EC_PM_SLP_S3# is low level.

PM_SLP_S3# never present until PCH_RSMRST# is high.

If I understood correctly, PM_RSMRST # is low.
Measure and show
3d3v_pwr
5v_s5
rsmrst#_kbc
3v_5v_pok
3v_5v_pok#
lid_close#
ac_in_kbc#
ecrst#
vd_in1, vd_in2

Hi, these are the readings:

3d3v_pwr= 3.31v
5v_s5= 5.02v
rsmrst#_kbc= 0.0v
3v_5v_pok=3.2v
3v_5v_pok#= does not exist. ¿?
lid_close#=3.2v
ac_in_kbc#= 0.0v
ecrst#=3.2v
vd_in1, vd_in2= 3.2v, 3.2v

Check Q1701.

Q1701 replaced.


Q1701 pin 1, 3, 4, 5, 6-->0.0v
Q1701 pin 2-->3.2v.

Diode reading pin 3--> .470

Check ADT_TYPE.

ADT_TYPE--> 0.44 volts with a 45w charger
ADT_TYPE--> 1.5 volts with lab psu and lenovo dc-jack adapter.

I will tray replacing kbc. (it is coming soon)

Sadly kbc replaced but nthing changes.

PM_RSMRST# are always at low level.



Any advice?