lenovo laptops

Hello guys! I have 3 different laptop with same problem: Lenovo ideapad 100( MB: NM-A681 ), Z50-70 (MB: NM-A272) and yoga 700. all of them power on, fan spinning, power light on, battery charging but no display. Made some measurement on edp port and i found that +LEDVDD 20v, +3VS 3V, but...

Lenovo BIOS series model: BIOS BVDT Note: Version càng mới càng tốt ( new as possible ) :D How To FIND PRODUCT NAME & SERIAL NUMBER? 100 Series (IdeaPad) 100-14IBY Laptop (ideapad) 100-15IBY Laptop (ideapad) 300 Series (IdeaPad) 305-14IBD Laptop (ideapad) 305-15ABM Laptop (IdeaPad)...