[SOLVED] Toshiba Qosmio x870 Video Issue

[MACTEP003]

Hi! I have Toshiba Qosmio x870 Gaming Laptop. My client gave it to me to repair. Laptop was dead. Will not turn on.
I have replaced Video Card NVIDIA Geforce GTX 670MX first. Will not Turn on. So I have replaced motherboard as well . Motherboard has latest firmware.

The computer turns on now and boots normally with just external monitor attached. As soon I connect internal monitor and try to turn it on, computer will turn on but it will not start. It will flash red power light for 5 seconds on and 5 seconds off.

It does the same with just LCD cable attached, without LCD. Replaced memory. I have replaced LCD cable and LCD - same thing. Now I'm puzzled. Could not find anything like that on any forum.

Any hint or help is greatly appreciated.
Thank You.

 

[MACTEP003]

Ok. Some update. It was motherboard. Defective motherboard. Replaced motherboard, Now computer starts with cable attached and displays video on screen. However video is screwed. Tried 2 other monitors. No video on them, just backlight.