Lenovo x270 no post problem help!!

[NConstantinou]

I have lenovo laptop which has all voltages on coils except PL402 near CPU 0V. when i power on keyboard lights comes on and then off but no POST.
I reprogram Bios but nothing.

Does anyone has any ideas!


Thanks.

[MAA]

Re: Lenovo x270 no post problem help!!

HEllo, i have the same problem...
I believe it is the motherboard which gone bad.
Note that this No-POST problem occured AFTER i updated my Bios Firmware via the Lenovo support website.

Were you able to resolve your issue?

[Stevedb]

Re: Lenovo x270 no post problem help!!

I would program the bioschip externaly with biosprigramler or try first to reset bios by removing the bios battery and short the pins for 30sec. If he has a bios battery.

Regards

[MAA]

Re: Lenovo x270 no post problem help!!

Hey, Thanks for your answer.
You say i should short the BIOS for 30 seconds:
it does have a BIOS battery, so do you mean that i should unplug the charger and laptop battery and then short the BIOS ?
In other words, the laptop shouldn't be powered ON during this procedure?

Thanks for your help mate!

[Stevedb]

Re: Lenovo x270 no post problem help!!

No if he has no bios battery then remove the battery charger and hold the powerbutton for one 1min or so of longer if you want.

[MAA]

Re: Lenovo x270 no post problem help!!

it has a BIOS battery...
So?

[Stevedb]

Re: Lenovo x270 no post problem help!!

Ok if it has a bios battery you can short the two pins for 30 sec where the bios battery is plugged in. The connector.

[MAA]

Re: Lenovo x270 no post problem help!!

Okay thanks,
so i removed the laptop battery and charger,
i unplugged the BIOS small battery and shorted the 2 pins of the connector for 30 secs.
Problem still there... black screen on startup, no POST.
i even removed the RAM stick and turned on the laptop, no beeps whatsoever, means the motherboard did not even notice that it has no RAM (again, this means there is a no POST).

[Stevedb]

Re: Lenovo x270 no post problem help!!

The bios battery is 3v?

What abouth connecting external keyboard with usb.can you toggle capslock or numlock?

[mcplslg123]

Re: Lenovo x270 no post problem help!!

@MAA, do you have a dc supply?? If yes, measure the consumption on your dc supply 01) With ram 02) Without ram?? If you dont have the dc supply, measure voltage on pin30 of Ram slot( I assume its DDR3-L).

[NConstantinou]

Re: Lenovo x270 no post problem help!!

i have set ps to 15v and ampere about 1A. power consumption is 0.02A with and without ram.

BUT i noticed ic PU701 13 (RT8606A) pin 4 which is power good has 0v.
i cut output track line of pin 4 for power good and ic does not output PG.
i beleive that is my problem.

one question.
the EN pin does not have any voltage also. does it come before of after PG!
do you have any boardviwe for this board! X270 NM-B061 Rev:0.1

i am waiting for replacement part.

Thanks.

[mon2]

Re: Lenovo x270 no post problem help!!

EN = enable pin for the regulator.

After the regulator is enabled and the output voltage is within the specifications, then the power good signal is available. Till then, the power good signal will remain LOW. This is the most common style of power good status signal.

[NConstantinou]

Re: Lenovo x270 no post problem help!!

Thanks

so i have to cut track of pin5 to see if there is any voltage going to IC in order to test if ic is ok!for EN pin

any boardview available for this model!

[mcplslg123]

Re: Lenovo x270 no post problem help!!

Dont cut the track for EN pin. Trace it back where from it is coming-most likely SIO. Resistance on EN pin??

[NConstantinou]

Re: Lenovo x270 no post problem help!!

After resoldering chip i manage to get EN on PU701 and Pg on pin5 BUT
most of the voltages are fluctuating.
3.3v,5v,12v and Bios 3.3v are constant.


i flash Bios but nothing.

on bios battery connector without battery i get 1.19v.

No power on.

does anyone has any ideas!

Thanks

[NConstantinou]

Re: Lenovo x270 no post problem help!!

Note:

if fan is spinning then all voltages are fluctuating including 3.3,5v and bios

[NConstantinou]

Re: Lenovo x270 no post problem help!!

I managed to power on laptop.
when is power on and i press power buttom keyboard light comes on, power buttom flashes 3 times and switches off.
i noticed on board there are 2 ic's and 2 coils for VCCGFXCORE.
PL401 has output BUT pl402 has no output.
PL402 resistance to ground is 0.07 OHMS (0V) and the other coils has 0.10 OHMS (1.0V)
The processor is solder on board.

is it a problem with BIOS or CPU. i flashed Bios but i do not no if file is good.

No beeps during power on.

Anyone has any ideas

Thanks

[piernov]

Re: Lenovo x270 no post problem help!!

https://logi.wiki/index.php/User:Pie..._I_solve_it.3F

[NConstantinou]

Re: Lenovo x270 no post problem help!!

Thanks Piernov for your reply
i am using x270 nm-b061 rev 4.0 schematic instead of rev:1.0
there are 2 NCP81382MNTXG ic's one connected to PL401 which is ok but the other
ic does not send output to coil. there are no mosfets.
BUT
when i connected everything the laptop show LENOVO logo, i press F1 to go to setup but nothing on display.

is it a problem with ic NCP81382MNTXG for pl2!

thanks

[NConstantinou]

Re: Lenovo x270 no post problem help!!

Now i managed to go to BIOS to setup date and time but when i went to press F10 to save
freeze.
still PL402 0v. when display was shown bios.