another U28 chip issue or...

Ok so my g4 chimes when on button is pressed, blank screen, fan runs - nothing. I was able to get it to start a couple of times and it would run a short time before shutting down. First time it quit after moving it a few inches. second time my g4 quit it showed vertical grey/blue lines, then blank-ish screen. Seemed like it was on but showing a blank screen.

Hoping to not change out the motherboard again (did so earlier this winter) and am game to try soldering the U28. Good candidate?