Lenovo G50-30 no POST on powerup

[mastsrl]

i'm having an idsue with a Lenovo G50-30, motherboard ACLU9/ACLU0 NM-A311
REV: 1.0

motherboard powers on(power LED), but no post, no video(internal or external), no beep, nothing.

All power rails check ok, i have all the ALW rails(5, 3.3, 1.8 and 1.0) on standby as well as the LP rails, i have also all the VS voltages and Vcore(0.76v) Vgfx(0.86v), Vsoc 1V and active voltages(Vddr at 1.35v, etc)

There's nothing on the screen, so it's not a no backlight scenario only.

reflashed bios with a dump that i got here: https://www.badcaps.net/forum/showthread.php?t=54053 with no result.

Also, pressing the power button for several seconds turns the motherboard off(so at least that logic is working).

¿any ideas?, ¿try another flash image?(flash chip seems to be ok, as i programmed it with blank check and verify and it passed everything ok)

[lapfix]

Try to Clean me region fo your dump .

[mastsrl]

Originally Posted by lapfix

Try to Clean me region fo your dump .

how to do that?, i've never done it before with a BIOS dump, i just googled and found wildly varying information

[Stevedb]

Hi upload your Biosdump and ask in the bios section to clean your dump somebody Will do it for you then. Regards Steve

[Duranitron]

measure the vcc of the bios ic.. also the rtc battery
.

[ktmmotocross]

just throw in other bios dump and ofcourse measure all coils for voltage

[mastsrl]

i already managed to clean the ME settings after finding a guide, it didn't work.
I also have another exact same model motherboard with another failure(blown EC), so i swapped flash chips between motherboards... nothing, same failure.

I dumped that motherboard flash and did a ME cleanup, same issue.

so far the bios i've tested are: one downloaded from the post i mentioned, no work
swapped flash chips with another exact same model, no work.
dumped that flash and cleaned ME region, no work.
everytime same failure, no video out(in fact, screen remains totally dead, it's not a baccklight on but no graphics, it's totally dead), only power led

@duranitron all voltages check ok, bios included.

i'm baffled

[mastsrl]

i've been sent another BIOS, with replaced DMI area.. exactly the same issue

[mcplslg123]

These sort of cases are very difficult to solve on soc structure. Still check ram clock/data signal(if u have oscilloscope better). Dramrst# on pin 30 of ram slot. All sys pwr good present??

[mauda]

Hello @mastsrl, did you find a solution? I have a very similar problem.

[mastsrl]

no, and it's getting to be quite an issue with the customer.

I haven't checked dramrst, but as i've said in the 1st post, ALL power rails that i could measure are present and good.

So far we think it's a fried CPU, it's not the first lenovo with soldered CPU that has died

[piernov]

Known good compatible DDR3L RAM?
Caps lock key triggering caps lock LED?
PLTRST# present?

[mauda]

@piernov
Known good compatible DDR3L RAM = yes, I tried.
Caps lock key triggering caps lock = no LED indication
PLTRST# present = 1.8V

Any other idea?

[mauda]

I will measure all power rails before/after power on again and write them here.
I hope that this motherboard is not death

[mauda]

Here are my measurements:

PL_coil = stand_by voltage, power_on voltage
===========================
PL301 = 20.4V, 20.4V
PL302 = 2.74V, 2.74V (without battery)
PL402 = 3.38V, 3.38V
PL404 = 5.1V, 5.1V
PL502 = 0V, 1.37V
PL601 = 1.8V, 1.8V
PL603 = 0V, 1V
PL701 = 0V, 1.06V
PL902 = 0V, 0.9V
PL903 = 0V, 0.78V

Voltages on:
EEPROM 1st pin = 1.8V
ETC battery = 3V
DRAMRST# = 1.34V
PLTRST# = 1.8V

Not measured:
PL101, PL102, PL201, PL202, PL401, PL403, PL501, PL602, PL901

Please, help ... what next should I check?

[mcplslg123]

You need to measure powergood signal of each and every pwm.

[mauda]

PG signals (coil>controller,PGpin = voltage):
PL402>PU401,pin2 = 2.8V
PL404>PU402,pin2 = 0.2V
PL502>PU501,pin10 = 1.37V when power_on
PL601>PU601,pin5 = 0.57V
PL603>PU602,pin2 = 3.3V
PL701>PU701,pin5 = 0.67V when power_on

PL902+PL903>PU901:
- pin8 = 5V
- pin15 = 3.3V when power_on
- pin22 = 5V
- pin27 = 3.3V when power_on

[mauda]

I also tried to measure some KBC pins (ENE KB9012QF A4).

[mcplslg123]

PU402, PIN2 POWERGOOD should be 3V.

[mauda]

Can you please explain to me why the PU402 pin2 is not connected anywhere in the diagram?