Yoga3 Pro-1370 NM-A321 - no power at all

[reassor]

Hey all.
Got this patient. Resistances seem ok all mosfets lookin good yet when i connect the "usb" type charger. There is ZERO voltage on the charger connector.

When i keep the probes on it long enough it will pulse to 18-19v then drops to 0 again. each pulse is sent about every 2-3mins. There is charge cap so when i meassuer on it it shows when the pulse was cause it charges up to 18v and slowly drains.

Tried other charger same shit (dunno if it was ok).

Do not have third.

Whats the mechanism of it turning on? (charger (ac adapter))

Cheers.

EDIT : can i just inject 20v on acin +?

[mon2]

Re: Yoga3 Pro-1370 NM-A321 - no power at all

Hi. Perhaps not strong enough tea for me but having some difficulty in following this schematic.

1) Where are you measuring the DCin power rail ? Is it @ JP23, pin # 5 ?

What is JP23 on your board ? Is it a Type C connector or this connector mates with a paddle board of some type ?

I have not yet checked the boardview file. If this is indeed to a paddle board then it makes sense -> the paddle board must contain some power delivery controller to negotiate the power delivery contract (volts & amps) to power this logic board.

Can you confirm this detail ?

Post pics or more details of the power adapter you have so we can review its features.

2) Then the negotiated power delivery contract enters on pin # 5 and proceeds to power the logic board.

3) Is the power adapter you are using, the official and recommended power adapter for this unit ? Is it confirmed to be working ok ?

[reassor]

Re: Yoga3 Pro-1370 NM-A321 - no power at all

1) yes pin 5
JP23 goes dorectly to Psu Plug

PSU is original lenovo ADL40WCG - its a usb --> usb with kinda like displayport side
2) i kinda figured its something like that (PD like)
3) cannot confirm if its working since i do not have a spare.

Had broken greencell lying around so i took apart the plug it has N channel mosfet inside and USB sda and scl were all bridged in it. I gave 20v on that plug to see if it does something - but the mosfet has 19.8 on gate and it does not open . So there must be trigger for it.

It might be a bad adapter (the orginal one) i just wrote to ya all here so i stop messing around and get to know how that particular AC adapter works.

Thx