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1 Posts

12-19-2015

United States

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Lenovo Yoga 700-14ISK - Battery not charging

2018-10-18, 13:43 PM

Yesterday my laptop stopped charging and I don’t know what to do... please help me!! :)

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32 Posts

08-18-2015

US

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Re: Lenovo Yoga 700-14ISK - Battery not charging

2018-10-18, 13:48 PM
Does one have a multimeter at hand? My first area to troubleshoot would be checking the charger tip for accurate voltage and if that shows good I would follow up with the actual charge port in the laptop (may be janked-up/broken).
If one can boot to OS: Go into device manager and uninstall all battery related "drivers" and reboot... may give joy?
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1 Posts

11-12-2018

AT

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Re: Lenovo Yoga 700-14ISK - Battery not charging

2018-11-20, 13:52 PM

I too had a not charging yoga700-14isk on my desk got from a friend. after a longer resarch i came to this thread
https://forums.lenovo.com/t5/Lenovo-Yoga-Series-Notebooks/What-s-with-the-Yoga-3-Pro-power-adapter-it-s-a-USB-charger-too/m-p/3963339#M60868
which pointed me to the right direction.


Summary: The usb adapter is a dual voltage atapter 5v normally without any yoga connected (or e.g. a cellphone) and ca. 20V  if the additional line (the adapters usb has 2 outer additional fingers - lets name it 5/20V control-line further) is pulled to 3.3V by a voltage divider (200Kohm to gnd) in the yoga in case pluged into.
In my case (which took me several 10H to realize) the input resistance (Yoga side) of the additional 5/20V control-line was 2.5Kohm instead 200K. The reason was that the parallel connected PD104, actually a TVS-ESD protection Diode - was blown ( a very tiny sod-882 device which I removed as first step -> 200Kohm -> charging was working again.

So my advise: check the input resistance first on the 5pin-MB connector in disconnected Yoga Battery and Power adapter situation to rule out the fault I had.
Actually, alternatively you can check the adapter by asserting 3.3V to this control line by a external power source (with e.g. a serial resistor of e.g. 5K) and check with the voltmeter that the Adapter output-voltage changes from 5 to 19-20V on the USB Vbus lines- normally pin 1,4.
Because The control line(s) are the 2 additional outer pins we are counting 1-6 on this special adapter usb-socket. therefore pin 1,6 are the control line - connected together by the charging cable, but only one used at the adapter side. pin 2,5 the usb voltage (5/20V). Pins 3,4 data bus  - unused and not connected at the adapter side.
Maybe I'll give some extra pictures if of interest.

In order for easy acces and checking the voltages/resistances - the MB-power(-USB) connector PJP1 pins are as follows:

Note: seen from above and connector at right side and counting from top to bottom.

 

1 - GND

2 - Control line (should be 3.3V if adapter connected)

3,4 - USB Data Bus

5 - +5/20V

good luck !

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03-04-2017

US

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Re: Lenovo Yoga 700-14ISK - Battery not charging

2019-11-05, 3:08 AM

I had the same issue and removing PD104 with two soldering irons fixed it.  

 

After my first cable stopped working, I was especially careful with my second. The computer stopped charging completely and I was hoping that the cable had just gone bad again so I ordered another, but that didn't fix the problem this time. I think what actually happened I accidentally plugged a USB cable in backwards into the charging port. I don't remember being especially rough, and there shouldn't be enough give to possibly do this. The root cause ended up being that the ESD diode PD104 was fried on my motherboard so the circuit was not correct to cause the charger to output 20V instead of 5V.

 

Lenovo made a huge mistake trying to be cute with their charger so that it could be used as a USB charger or a laptop charger. Just put a charging port on there and don't mux it with a USB port, especially if accidentally plugging in a USB device backwards stops the computer from charging completely. If I weren't a EE/CE this probably would have caused me to have to replace the whole motherboard or buy a new laptop.

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