Lenovo S230U does not power on.

[soker]

Hello! I need help please.
The Board Compal LA-8671P Rev 1A_1004A does not turn on. green LED lights, Battarie is charged, 3vLDO and 5vLDO are there. When pressing on the switch, the fan turns for 4 seconds and then it is out again.

measured voltages:
+ VCC_GFXCORE_AXG = 0V
+ CPU_CORE = 0V

when i press the switch, PM_SLP_S3 #, PM_SLP_S4 #, PM_SLP_S5 # rises to 3.2 V and then immediately back to 0V
+ 3vs, + 5vs, + 1.05VS, + 1.8VS, + 1.5VS, + 0.75VS only appear if PM_SLP_S3 #, PM_SLP_S4 #, PM_SLP_S5 # are set to 3.2V.

+ USB_VCCA = 0 v

Measurements on PU901

VCC = 5.01v (when I press the switch, otherwise it is at 0v)
VR_ON = 3.2v (if I press the switch, otherwise it is at 0v)
CPU_B + = 20,1V
VRMP (pin 10) = 20v
VR_HOT # = 1.05v (if I press the switch, otherwise it's at 0v)
VGATE = 3,3v (if I press the switch, otherwise it is at 0v)
PVCC = 5.01v (when I press the switch, otherwise it is at 0v)
HGA = 0v
HG1 = 0v
VR_SVID_CLK = VR_SVID_ALRT # = 1,05v
VR_SVID_DAT1 = 1.05v

Measurements on PCH

PCH_PLTRST # = 0v
SYS_PWROK = 3,3v
EC_RSMRST # = 3.2v
PCH_RSMRST # = 3.2v

+ 3V_PCH = 3.3v appear all the times
+ 5V_PCH = 5v appear only for a few second

listen to this links, it show how the board ist doing: https://youtu.be/sG1rC-Rfsl8

MOD EDIT: Link to schematic -> https://www.badcaps.net/forum/troubl...671p-schematic
Thanks for your help.

[Weelcup]

Re: Lenovo S230U does not power on.

Hi
Did you flash the bios? If so, did you back up its original bios?

[caspian]

Re: Lenovo S230U does not power on.

it seems PU901 and/or its connected Mosfets are defective. First, test PQ1001 to PQ1006 for being shorted or being defective. I addition, check all pins of PU901 for bad voltage or being shorted. all the other components of your laptop seem fine.

[soker]

Re: Lenovo S230U does not power on.

hello,
thank you a lot for the reply,

i check PQ1001 to PQ1006 but i did not found any short.

here are the resistence values of the Pins with respect to Ground

the values in the parenthesis are the Voltages:
( When i plug in the charger / when i press the power button )

PQ1001

pin 1, 2, 3 = 0 ohm (0v/0v)

pin 4 = 8,5 ohm (0v/0v)

pin 5, 6, 7, 8 = 3,8 ohm (0v/0v)


PQ1006

pin 1, 2, 3 = 0 ohm (0v/0v)

pin 4 = openline (0v/0v)

pin 5, 6, 7, 8 = 2 ohm (0v/0v)


PQ1002

pin 1, 2, 3 = 3,8 ohm (0v/0v)

pin 4 = 8,5 ohm (0v/0v)

pin 5, 6, 7, 8 = openline (20v/20v)


PQ1005

pin 1, 2, 3 = 2 ohm (0v/0v)

pin 4 = openline (0v/0v)

pin 5, 6, 7, 8 = openline (20v/20v)



here are the resistanve values and voltage on PU901


pin 13 = 10 ohm
pin 24 = 3,8 ohm
pin 32= 4,9 ohm
pin 33 = 3,9 ohm
pin 35 = 0 ohm it is Ground
pin 42 = 2 ohm
pin 49 = 2 ohm
pin 60 = 1,7 ohm

all oder pins are over 50 ohm.


i am getting following voltages

pin 10 = (20v/20v)
pin 1, 2 = (4,9v/4,9v)
pin 48= (0v/4,9v)
pin 49= (0v/0v)
pin 46= (0v/0v)
pin 45= (0v/0v)
pin 24= (0v/0v)
pin 13= (0v/0v)
pin 12= (0v/3,2v)
pin 11= (0v/0,9v)
pin 4= (0v/3,2v)
pin 36= (0v/5v)
VR_SVID_CLK=VR_SVID_ALRT#=VR_SVID_DAT1= 1,05v the only apear when the board is trying to start.

schould the voltage not appear at CSREFA (Pins 49) and CSREF (Pins 49) when i plug in the charger? may be PU901 musst first provide these Reference Voltage

[soker]

Re: Lenovo S230U does not power on.

hello Weelcup,

i did not flash the Bios.

how can i check it using the mutimeter?

[caspian]

Re: Lenovo S230U does not power on.

the problem is not related to CSREFA and CSREF . your resistance readings are very low. Ich glaube PU901 und PQ1001 bis PQ1006 sollten alle ersetzt werden. aber es kann teuer werden.

[Weelcup]

Re: Lenovo S230U does not power on.

hello Weelcup,

i did not flash the Bios.

how can i check it using the mutimeter?

it doesn't need to be checked via multimeter. I just wanted to exclude the bios from the equation as I had a problem of shutting down in seconds with bios issue. but as much as it is the original then no worries.


I agree with #Caspian. your resistant readings are low.

[soker]

Re: Lenovo S230U does not power on.

hey i disconect PL1001 and PL1004 and check the values of resistances.

for PL1001

on the Mosfet site i have 2 kohm and the oder site 4 ohm


for PL1004

on the Mosfet site i have 2 kohm and the oder site 2,3 ohm


on PU901 i get

Pin 24 = 4ohm
Pin 32 = 2kohm
Pin 33 = 2kohm
Pin 34 = 110kohm
Pin 41 = 110kohm
Pin 42 = 2kohm
Pin 43 = 68kohm
Pin 49 = 2,4ohm

when i press the power and check the voltage , i some time get 0,9 v on pin 1,2,3 of PQ1002 and 0,3v on pin 1,2,3 of PQ1005.


i also purchace a new PU901 and PQ1001 to PQ1006 the will comw latter

do you think that the PCH and CPU coud be defekt? because the have a low resistance on the line +CPU_CORE and +VCC_GFXCORE_AXG?

i dont anderstand what the following instruction meant (Choke PN:SH00000JX00
DCR=1.33~1.396m ohm) ist is on page 48 of the schematic. pleace could you explane me that?

thank you!

[soker]

Re: Lenovo S230U does not power on.

hey

I read on internet that one of the Bios-chip must have Voltage on the Pin 3 and 8 when i only plug in the charger but dont power the Board. is it true?
in this case with BIOS-chip must have the Voltage before i power the board?

thanks

[Conste]

Re: Lenovo S230U does not power on.

Yes that is right. BIOS Chip and KBC / Super I/O must habe 3,3v to start the device, as far as I know actually
KBC seems to have 3,3v in your case

[on/off]

Re: Lenovo S230U does not power on.

hey

I read on internet that one of the Bios-chip must have Voltage on the Pin 3 and 8 when i only plug in the charger but dont power the Board. is it true?
in this case with BIOS-chip must have the Voltage before i power the board?

thanks

It's depend what them design, when KBC have 3.3V from +3VLP. That enough to power KBC and give command to any regulator to power up. While supply for bios come from switching 3ALW to 3VS need triggering from SUSP signal. (this signal appear after pressing on/offbtn#).
Already you've prove that VS voltage present even only momentary

[caspian]

Re: Lenovo S230U does not power on.

I was busy these days. Sorry that I could not answer early. It seems that the CPU is defective and the PU901 circuit is fine. Before buying or replacing PU901 , if you have got a BGA machine, remove the CPU. solder PL1001 and PL1004 back on the mainboard. then measure voltage on these coils again. Unfortunately, the CPU is soldered. So testing the circuit gets difficult. Do not replace PU901 and the Mosfets.

[piernov]

Re: Lenovo S230U does not power on.

Usually CPU VCore will not be produced if the CPU doesn't request it. (to the CPU buck controller through SVID). Also, VCCGFX is usually produced only after BIOS is running, and in several cases it requires the internal display to be recognized.
Before the CPU can request CPU VCore, UNCOREPWRGOOD has to come high, meaning VCCSA and VCCIO are good. On this platform you can measure it on R28. On some platforms it's not available to measure, so you have to rely on the signals that come up before like SYS_PWROK or PCH_PWROK.

Better try to replace PU901 before trying to desolder CPU, but this rarely solves the issue on those platforms. Even more so on Haswell and newer where the CPU die way more easily than earlier platforms.
Also make sure there's no knocked off component or liquid damage near PU901 circuits.

Also make sure the 25Mhz PCH clock is ok.

PS: didn't read the whole thread so sorry if I missed something…

[caspian]

Re: Lenovo S230U does not power on.

that us right. It is possible that both the CPU and the PU901 circuit be fine. In that case, desoldering the CPU and PU901 is useless. So make sure before doing any desoldering.

[RJARRRPCGP]

Re: Lenovo S230U does not power on.

Even more so on Haswell and newer where the CPU die way more easily than earlier platforms.

Are you sure you don't mean Skylake or newer?

Skylake was when Intel was confirmed to have the ultra-thin layer that easily bent under heatsinks, LOL. It's thinner than even Haswell!

[soker]

Re: Lenovo S230U does not power on.

thank you all for the reply.

i check some voltage like @piernov said and i found this

SYS_PWROK = 3,2V when i press the power else it is 0v

PCH_PWROK =3,2V when i press the power else it is 0v

VCCSA = VCCIO = 1,05 V when i press the power else it is 0v

H_CPUPWRGD = 0 V when i press the power it is still 0 V and is not shorted

look at this video: https://youtu.be/sG1rC-Rfsl8