Dell latitude 5591 not power on

[lapfix]

Hello friends
Got this mtherboard not power on

Dell latitude 5591 , LA-F711P.

No short , no suspicion area , all is clean.

All voltage at S5 are present .
PM TABLE =
+5V_ALW
+3.3V_ALW
+3.3V_ALW_DSW
+3.3V_ALW_PCH
+RTC_CELL
+1.8V_PRIM
+1.0V_PRIM
+1.0V_PRIM_CORE
+5V_ALW2
+3.3V_ALW2
+3.3V_RTC_LDO
+1.0V_MPHYGT

Timing Diagram for S5 to S0 mode =
All is Ok until step 8
8 = SIO_PWRBTN# = 3.3v
PCH_RSMRST#_AND = 3.3v
But the PCH don't send SIO_SLP_S5#

All the power supply for PCH are present , when power button is triggered , POWER_SW#_MB 3v becomes 0 than 3 and that's the normal but SIO_PWRBTN# the signal send from io to pch to tell the PCH to get out of S5, and then go to S4-S3-S0 stay at 3V

did i miss something to chek !

[mon2]

Re: Dell latitude 5591 not power on

Remove all power. Meter in resistance mode.

Check the resistance to ground of SIO_PWRBTN#.

Actually, it should be ok since it is high...

Check for the existence of the cap @ cc269.

[lapfix]

Re: Dell latitude 5591 not power on

Remove all power. Meter in resistance mode.

Check the resistance to ground of SIO_PWRBTN#.

Actually, it should be ok since it is high...

Check for the existence of the cap @ cc269.

Thank you my friend

Resistance to ground of SIO_PWRBTN# taken at CC269 = 2.123mohm so it's good.
Yes cap is populated , not RC241.

i think when power button is trigged than SIO_PWRBTN must be 0v than 3v !

[mcplslg123]

Re: Dell latitude 5591 not power on

RTCRST#/SRTCRST# and LIDSW# checked?? Bios flashed??

Not gone thru scheme yet but just reminder to see if u missed these points.

[lapfix]

Re: Dell latitude 5591 not power on

Thank you mcplslg

PCH_RTCRST# = RH200 =3v at 2 sides
SRTCRST# = RH201 = 3v at 2 sides
LID_CL_SIO# = RE26 = 3v at 2 sides

Try another bios version still the same

[mcplslg123]

Re: Dell latitude 5591 not power on

PCH_PWROK/PCH_DPWROK/PCH_BATLOW#/AC_PRESENT-Status??

[lapfix]

Re: Dell latitude 5591 not power on

Ok , but i think that this step are not reached ! i m stuck at step 8

PCH_PWROK = step 14 not reached yet
PCH_DPWROK = RE536 = not populated = 3.3v at the 2 points
PCH_BATLOW# = RH94 = 3v from 2 sides
AC_PRESENT = RH243= 3v from 2 sides

[sikocan]

Re: Dell latitude 5591 not power on

Can you check resistance of all caps on the PCH module. As well as measure V of CMOS battery outside board and in the board.

[lapfix]

Re: Dell latitude 5591 not power on

thank you sikocan

V of CMOS battery outside board and in the board. = 3v
all caps on the PCH module = more precision please !

[sikocan]

Re: Dell latitude 5591 not power on

I'm trying to identify if PCH has an issue. Any low resistance on caps on the PCH chip itself? This method saved me many hrs of work before.

[sikocan]

Re: Dell latitude 5591 not power on

I feel like this looks like a XPS 15 motherboards. Physically board looks good? Check around TPM module, any caps with corrosion? I've had TPM_VDD power had issues on similar model.

[lapfix]

Re: Dell latitude 5591 not power on

I feel like this looks like a XPS 15 motherboards. Physically board looks good? Check around TPM module, any caps with corrosion? I've had TPM_VDD power had issues on similar model.

Thank you

Nothing unusual around pch or UZ12

[sikocan]

Re: Dell latitude 5591 not power on

Did you check resistance of all these rails attached?
Also, a dangerous method, but I end up using this in last case scenarios, inject V to each power rail according to their specs and see what happens. Components like CPU GPU ram etc will get power etc but your looking for abnormalities in amp consumption.

[lapfix]

Re: Dell latitude 5591 not power on

Did you check resistance of all these rails attached?
Also, a dangerous method, but I end up using this in last case scenarios, inject V to each power rail according to their specs and see what happens. Components like CPU GPU ram etc will get power etc but your looking for abnormalities in amp consumption.

Thanks again.

i can't reach S3 , as i mention before SIO_PWRBTN# the signal send from io to pch to tell the PCH to get out of S5, and then go to S4-S3-S0 stay at 3V and not go to 0v than 3 V.

at page 47 i just reach the step n8 , step 9 = SIO_SLP_S5# it's not generated .

Yes maybe i will try this dangerous method

[sikocan]

Re: Dell latitude 5591 not power on

Something in the board knows there maybe an jssue down the line of power rails hence it's not allowing it to turn on, brute force it baby.

[lapfix]

Back for this Laptop.
With charger consumption = 0.028amp..and not trigger on.

All the voltages that i mention before are present.

I started from the beginning ..PQ9 and PQ4.
PQ9 = S 19.5v / G 9.31v / D 19.5v So good
PQ4 = D 19..5v / G 18.5 v / S 13.21v..this is my issue .

So gate of this PQ4 must be low and there's a voltage divider = must be 1.75V
no high voltage on PQ7 = voltage divider not woking

As mon2 mention at his post , the voltage of VBUS2_ECOK must be a high enough voltage to enable the mosfet @ PQ4.

#48
https://www.badcaps.net/forum/troubl...e3#post1729109.

So.The GATE pin must be lower to enable.

I Attach a ground wire to the bottom pin of the bottom resistor PR16 Test and it replaced mosfet enables.
.
So why VBUS2_ECOK is not high !...there's no short , all resistrances values are correct !

I try to power on my motherboard via a type-c charger and i didn't find my oridinary voltages!

PQ1206 =votage not stable swing between 0.600v to 1.5v
Diode mode = Drain to S = 0.549v ok
resistance mode = D to S = 2.677 mohm ok

PQ 1213 = Same behaviour of voltage swing

PQ 1202 = same behaviour of voltage swing.

So what to check else

[lapfix]

Update
I verify some measurements at P48 :
PQ1B is High ( turned on ) so PQ1A is Low (turned off)
Wich cause at the gate of PQ5 same as source so is turned off.
But PQ7 is OFF due to the absence of VBUS2_ECOK at his gate.

UT5 = PD controller
+TBTA_Vbus_1 = must be 20v in normal condtion..or 5v/ nothing in case of issue..but i got a non stable voltage , swinging between 0.6--1.2 v..PQ1206 is not shorted .

[lapfix]

Update 2
I try with another original charger ( lenovo ) PD controller is OK
all voltage are present...But same as with charger ...no VBUS1_ECOK

same too : no power light indicator , no caps light

[lapfix]

ue1
VBAT 3.1v
VTR_ANALOG 3.3v
VTR_PLL 3.3v
VTR_REG 3.3v
VTR1 3.3v
VTR3 RE340 pin 2 = 1.8v
SIO_SLP_SUS# 3.3
AC_PRESENT 3.3v
LID_CL_SIO# 3.3v
PS_ID 3.3v
RESET_IN# 3.3v
SYSPWR_PRES at RE57 not populated : only side 2 = 3.3v but
POWER_SW_IN# 3.1v
ALWON 3.1v
ACAV_IN 3v
RTCRST_ON 0v ok
SIO_PWRBTN# 3v

[mon2]

Test the crystal / clock @ MEC_XTAL1 / MEC_XTAL2_R.