Q: I have a powerbook G4 15" 1.67. When I open it up the lower half of the display is either black or greyish. Moving the screen back and forth makes it go away sometimes but other times not. What can I do to resolve this?

Most of the time, a change in the displayed image when you move the the display on its hinges indicates worn video cabling. Apple no  longer works on these models so you'll be looking for third-party repair shops.

We are at a handicap becasue you didn't fill in the "Geographic location" field in your profile. This is a big world and these international forums. if you post an approximate location, we can see if there are some recommended shops.

Also post if you are comfortable doing the work yourself. There are some online resources and instructions  for servicing these Macs.

I'm in the same boat as kommandant.  Two days ago I averted dropping my Powerbook Titanium G4 laptop by sharply tilting it to its side when I nearly tripped and fell.  After that I could see my cursor and upper screen while the lower half of the screen went black.  By fiddling with the display I could make the entire screen appear, yet the lower half was a shade darker tint and the cursor seemed to "disappear" under it.  Now, the screen is never clear enough for me to be able to see the cursor move, the lower 1/3 of the screen is always black, and the upper screen visbly starts to fade white.

After finding your response, I googled "worn video cable powerbook titanium g4" and found the ehow article "How to Repair Garbled Video in a Powerbook G4".  But, I don't have a #8 Torx screwdriver and there are not enough pictures of what hinge caps, composite ports, and composite plugs are for me to feel comfortable with giving it a college try.  Can you please help me with better illustrated, step-by-step instructions and also route me to third party help as I may be too chicken?  I'm in Indianapolis,IN USA.