HP DV7 No display

[anno]

hi

i have hp dv7-4010sd without display. I have cpu core voltage, so i think problem is in display (gpu / gmch?).

this laptop uses gmch and gpu for display then it is muxed?
i don`t have LCDVDD (disp_on) on lcd connector. now i am confused and don`t know what to check. Does the display on signal coming from gmch (northbridge of gpu?) Does the gpu (ATI) only work when there is more graphic power needed?

[gcomputers]

Re: HP DV7 No display

reflow ati chipset first that model have to much problem with him,non grafic chip

[anno]

Re: HP DV7 No display

ok . i did a reflow but still black screen
i see vgacore voltage is fluctuating , not stable. i measure on vgacore coil 1.0 ohm to ati gpu. i think that is to low? is there a short in ati gpu?