ibook g3 graphics card

i just bought an old 3g from my neighbor and it has screen issue where the graphics card gets loose. I took the back off and heated the card up with a heat gun and i am now able to get the screen to actually light up and it starts up dark gray and then fades to light gray. I am pretty shure it is a hardware and what can i do to fix this( if it is fixable). also it starts and does the chime but the screen does not turn on the first time but if i hold the power button until it is off and then press it again it will turn on the backlight. I also did the shut down key command and it shuts it down so it is able to boot to the os. if the screen is grey on the computer would it be the same on the external display?