lenovo yoga 260 power issue

[usuaia]

hi all

i need an advice, i have here a yoga 260 which make absolutely nothing if powerbutton pressed. if i plug in charger i have all power indicator flickering very fast, and also charger indicator is flickering...

i opened back and i could hear a flickering component around y6 (see picture), i cheched with finger if something geting hot and then, guess what? as soon as my finger is on component it stops flickering, all indicators stop flickering and i have a charging battery...

bud still no power on

any advise where to start troubleshoot?

[mon2]

Re: lenovo yoga 260 power issue

Hi. The referenced component is a clock crystal and used for your real-time clock circuit (RTC). It is used to retain your configuration of your hardware (ie/ hard drive parameters, boot sequence, etc.) and your calendar / time settings. Often the RTC chip is powered from a coin cell battery like CR2032 or similar.

Odd that placing your finger on this crystal helps but that means you are changing the load capacitance of this local circuit. Regardless, if required, these crystals are very inexpensive (< $ 1USD) but would recommend to review the power supply rails for this logic board and see if this issue still persists.

Personally have not checked but are schematics and boardview files available for this model ? If yes, please reference or post them. Will check back later (after I think a father's day pizza takeout .

[usuaia]

Re: lenovo yoga 260 power issue

hey mon2

hope the pizza was

thanks the quick reply, i found a schematic, see attached, bud no boardview.

i try to give some more information. if finger is on component i have good voltage for example on battery line, if finger removed, my voltage start to jump up and down....

can you help me to find the power rails to check?

[mon2]

Re: lenovo yoga 260 power issue

hi. pizza was great thanks.

Apparently there are 2 versions of this logic board. Your logic board matches the shared schematic ?

Can you take some clear and zoomed up pics of the same region that you are touching ?

Is it possible that you are touching the nearby surface mount 24 Mhz crystal @ Y5 ? This appears to be the input to a PLL for this logic board. The same results will happen if touching with a finger in that the load capacitance of this part will change and you will impact the clock frequency of the logic board. Most likely slow it down but that is only a guess at this time.

Is it possible that you are flexing the PCB during these touches ? Perhaps a bad solder joint that is mating once you touch / flex the board ?

With your meter in DC volts mode, check the voltage readings at the following points:

1) DCIN from the external power adapter - point 1 (before the fuse - fuse is likely white in body color) - post some clear pix of this area so we can all confirm the parts on the logic board.

2) DCIN power rail AFTER the fuse - point 2 - it should be the same as the DCIN from the raw power adapter.

[usuaia]

Re: lenovo yoga 260 power issue

you are right, there is 2 versions of the board, i just found the rev.1 schematic, my board is rev.2.
so far i think its the closes i get...

i get 20.55v on both sides of pf2 (blue arrows in picture) bud i get jumping voltage on red arrowed pins..

furthermore i found a screw damage on q170 (picture), whats this line for?

i tried to make a picture of region around y6...