Lenovo g50-30 self power up and dark screen

[nels]

hi all,

aim trying to repair a lenovo g50-30

black screen ,just led and dvd start.
hdd not turn on and wen i plug the charger its power on (just leds..)

any idea?

thanks

[pyry]

First check with a flashlight the screen has an image
you should see some letters or something like that
if you see something check these signals
LID_SW #, INVT_PWM, DISPOFF # should have 3v

[piernov]

Check if you have CPU VCore, if it's there, try flash the BIOS.

[nels]

thanks for reply

pyry: nothing on screen ,nothing on external screen vga port.

piernov :bios is mi first thing ,i use arduino+serprog to flash but 3.3v chip,
this chip is 1.8v need to find the way to program 1.8v chip...,but i have replaced the chip it one from another motherboard ,same motherboard and same bios the symptoms still the same.

cpu (pl902)= 0.945v
on 5v (pl402)=5.18v
on 3v (pl401)=3.480v

3v at 3.480v its normal ?

thanks

[Luaina]

Check for lvdsvdden. It should be 3.3v. If it is not present, reflow the graphic card or reball

[nels]

thanks Luaina,

but this model have integrated video on cpu.

and its power up (just led) when charger is plugged .

[Luaina]

Originally Posted by nels

thanks Luaina,

but this model have integrated video on cpu.

.

All the things that you just described points to the faulty graphic card (And yes, it includes the integrated one). The last asserted signal before POST which enables the LCD is LCDVDDEN. That's why It's a good idea to check it and act accordingly.

[Chieftain]

Friend your problem is a defect bios chip... I replaced the bios chip with a 3.3v chip from another vendor with double capacity (16mb) and my laptop posted... Ofcourse with warning message : " Bios vendor is not in the Lenovo's vendor list" but after 5 secs laptop continues fine... Find another same or similar Bios chip and flash it . I also sharing w you the bios dump .. My model is NM-A272 With i3 and w/o extra VGA.