Q: Screen rendering issues on PowerBook G4 Aluminum

Hi there. I am using an old PowerBook G4 Aluminum 15" just for some older programs that I still have, the specs are 1.33 GHz, 1 GB DDR SDRAM, a Model A1095 (I believe). It is running Tiger OS 10.4.11.

I am having some issues with the rendering of images, windows and icons on the screen. Sometimes, say if there is a background image, there will be pixels of a pure purple and a lime green color, and other areas of these colors in blotchy patches, which fade in-and-out in intensity. There will be a purple halo around icons on the desktop, and windows will have their title bar underlined by purple, and the window itself will also be outlined in purple. When I move these icons and windows, the color outline moves with it –the same for images with these blotchy patches. If I try to take a screenshot, it looks like it has taken this effect, but when the screen goes back to normal, the images do not show the discoloration.

There is also a sort of horizontal wind shear effect that comes and goes, like a Photoshop effect, that seems to effect the entire screen –but it hasn't been doing so lately, moreso just the blotchy colors. Neither the wind shear effect nor the blotchiness are affected by screen position.

These are intermittent issues that come and go, sometimes they may not happen for a few hours or days, and other times they keep coming back and staying –they also vary in intensity, sometimes just annoying, other times rendering the screen so poorly that I have to do a hard shutdown with the power button.

I connected this laptop to an LED TV (via a DVI to HDMI cable) when I was having these blotchy patches on the laptop's screen –and the TV screen showed fine, no blotches.

After asking some Apple Techs, they thought it could be anything from:

- the screen has gone off –but why would the discoloration move when I move the images/windows/icons?

- a bad laptop screen cable

- the video card –but it's rendering the screen image fine when connected to a TV?

- memory on the logic board

- improperly seated RAM (which I removed and reseated a few times with the same results)

Or a combination of these. They say it's not a HD issue.

I understand it's an old computer and old technology, but I would still like to get it back to normal, as everything else is working fine. I know a guy who can replace the screen and the cable, as it seems a little delicate for me to do –he wouldn't touch the video card. I'm leery about doing this as it may be other things causing this problem.

Also, the Graphics Card is an ATI Mobility Radeon 9700, Model: ATY, RV360M11 –if this helps.

Any ideas –thanks. (Please keep it relatively simple, if possible)