Lenovo Yoga2 13- No display and light only on keyboard

[ravi_1617]

Re: Lenovo Yoga2 13- No display and light only on keyboard

Thanks i will check , and update you soon .

[ravi_1617]

Re: Lenovo Yoga2 13- No display and light only on keyboard

Just an update now what went wrong while testing board ON & OFF, fan not spinning ,Showing short at PL802 +1.05V. opened jumper PJ801 ,L1,2,3,4,5,
couldn't find exact component .nothing heating
now no power at PL704 ,PL502

[mhf0000]

Re: Lenovo Yoga2 13- No display and light only on keyboard

It's 5 seconds LED on and I have a board with the same issue. If somebody has an idea what to to.. I would me more than happy.

I checked 19v, 3.3v, 1,35v, 5v... all on.. CPU 1.68v is also coming up.

It's consuming 0.06 till 0.010 Amps in IDLE. And while power on (till power off in 3-5 seconds) 0.280 amps.

hi i have the same problem yoga 2 pro turn on then off no signal the problem was the cpu after reballing the cpu it works again normally if cant make a reball process just heat it for 2 min on 250 degrees it should fix your prblem

[webwicht]

Re: Lenovo Yoga2 13- No display and light only on keyboard

When reading out the bios rom chip (WINBOND) from my Lenovo yoga 2 13 with a faulty flasher I damaged the bios rom chip and possibly other devices. (The CH341 flasher sent 5V instead ov 3.3 V to the lines)

I had a backup of this rom on the hd and flashed it into a new rom chip.
Now when powering on: the keyboard light is on and the fan runs for a couple of seconds but the screen stays black. (This is better than with the damaged bios chip where the fan did not run and the laptop power cycled in an endless loop)

Any hints what I could try before buying a new motherboard?
Thank you in advance.

[webwicht]

Re: Lenovo Yoga2 13- No display and light only on keyboard

I have 2 ideas what to do:

1. The Bios and EC version was 1.15 whereas the Bios-backup was 1.17
1V$96CN31WW(V1.17) since I downgraded it in the wrong hope some wifi cards would be accepted.

Must EC and Bios match? If so I need to prepare a downgraded Bios or upgrade the EC.

2. Since the faulty flasher sent 5V it might be that the ITE chip burnt. If so I could replace it.

What is the expert's suggestion?

[webwicht]

Re: Lenovo Yoga2 13- No display and light only on keyboard

I checked the signal lines of the 25Q64FSVSIG chip where I flashed the bios-Binary to and actually a short data transfer occurs. So I would assume ITE is not dead yet.

[baddjavo]

Re: Lenovo Yoga2 13- No display and light only on keyboard

I have similar problem yoga 2 13 , power led on for few second then off, repeating.
Notices 1.7V on core voltage coil PL704, is this normal voltage ?

[baddjavo]

Re: Lenovo Yoga2 13- No display and light only on keyboard

I checked lost of signals, its not thermal alert, core voltage is 1.73 volts.
Problem solved using virgin bios Ala_borbe provided on this forum.

[mon2]

Re: Lenovo Yoga2 13- No display and light only on keyboard

Well done. Thanks for your update!