Lenovo ideapad 110 no power

[jokophp]

Re: Lenovo ideapad 110 no power

Mod EDIT: bad advice

[KvnTM]

Re: Lenovo ideapad 110 no power

try to reball chipset..

Not the problem here. His problem is on the 5v rail which has nothing to do with the chipset and this laptop doesn't even have one.
The chipset (PCH) is integrated into the CPU package.

EDIT: thanks piernov for marking jokophp's response as bad advice.

[asem18]

Re: Lenovo ideapad 110 no power

Sorry to be late...thank you for all your help...PU401 (3VALW) is ok. My issue is on PU402 ( 5VALW ).

PU 402 :
Pin 2 to 5 = 20V is present
Pin 12 = 3.3v +5VALW_EN is present
Pin 15 = LDO +5VLP is not presnet ...only 0,635V
Pin 20 = +5VALW is not present ...only 0,635V.

I open PJ406 with the inductor soldered to the board and no too = same voltage.

I desolder and re-solder PU402 = same measure ...no change

[mcplslg123]

Re: Lenovo ideapad 110 no power

What about pin9 & pin 17of PU402??

[asem18]

Re: Lenovo ideapad 110 no power

Pin9/17 = 0V

[asem18]

Re: Lenovo ideapad 110 no power

PU401 :
Pin 9 = +3V_PWRGD = 0V
Pin 13 = 0,653v....PC411 = 0.653 ( from the side of pin13 ) , and 3.3V from the other side

[KvnTM]

Re: Lenovo ideapad 110 no power

PU401:
Pin 9 should be 3.3v if it's not active low.
Pin 13 is fine. It is the feedback signal which is ac coupled. Thats why you get 3.3v on one side and 0.653v on the other side of PC411.

PU402:
Replace the chip. I highly suspect that it is dead.
VCC pin (17) is odd. It is marked VCC and goes to gnd via a cap. Not quite sure what's the deal there. It is marked +5V_VCC but that rail exists nowhere in the schematic.
Can you take a closeup picture of PU402?


Sadly there are no datasheets available for both PU401 and PU402.

[asem18]

Re: Lenovo ideapad 110 no power

[KvnTM]

Re: Lenovo ideapad 110 no power



Those two components look kinda burned.
Also have you tried resoldering PU402 & PU401? The soldering doesn't look very trustworthy in my opinion.

Reflow them with a lot of flux. If this doesn't work I'd resolder them with lead free solder.

Everything seems to be fine. Either the soldering is bad or both chips died.

[SMDFlea]

Re: Lenovo ideapad 110 no power

PL402 should be 3.3µH according to the schematic .

[KvnTM]

Re: Lenovo ideapad 110 no power

PL402 should be 3.3µH according to the schematic .

He didn't mention that he replaced that inductor. I didn't even pay attention to it but that could be an issue. 1.5uh is definitely too low if he replaced it.

[SMDFlea]

Re: Lenovo ideapad 110 no power

It is to low,so feedback won`t work as it should.I agree with KvnTM about the soldering, need more flux.

EDIT: feedback should be ok,my mistake. 1.5uh (according to LA-C341P schematic) is rated at 6A whereas the 3.3uh is rated at 6.5A .

[asem18]

Re: Lenovo ideapad 110 no power

KvnTM and SMDFlea..a big thank for your help....no i didn't change inductor,as i told U before this mobo is coming from another reapir shop..ok i m gonna reflow both of them with a lot of flux...ok i will change the inductor with one 3.3µH

[KvnTM]

Re: Lenovo ideapad 110 no power

KvnTM and SMDFlea..a big thank for your help....no i didn't change inductor,as i told U before this mobo is coming from another reapir shop..ok i m gonna reflow both of them with a lot of flux...ok i will change the inductor with one 3.3µH

Yes.. I remember you said that it came from another shop.. I forgot.
They probably screwed that area up. Resolder both chips and replace the inductor.
I can remember that pu402 was getting really hot? This may be due to the wrong inductor.

[asem18]

Re: Lenovo ideapad 110 no power

Hello , i resolder PU402 & PU401 , i replace inductor with another one...same issue no 5Valw...and for Pu 401 3Valw is present but no +3V_PWRGD on pin 9.
maybe Pu402 is bad !
i will change it ..thank you for all your help

[KvnTM]

Re: Lenovo ideapad 110 no power

Just replace both chips if you already have to order one. The 3.3v chip is also not working correctly... PGOOD is missing from it.