More theories on the PowerBook G4 15" (FireWire 800) 'white spot' issue

Our continuing investigation (see parts 1, 2, 3) of the PowerBook G4 15" (FireWire 800) white spot issue has led to a few new theories about what might be causing the problem, including Mark O'Neill's concave screen hypothesis:

"When I close and latch the screen on my PowerBook, I notice that the corners of the housing sit about .5 mm higher than at the center section where the latch is located. I was curious to see if this had a 'physical' effect on the screen, I placed a straight edged ruler along the back of the screen housing near the top/front edge and noticed that the housing was just a 'tiny bit' concave. I repeated this same 'test' with the lid open to see if maybe 'pressure' from the latch mechanism was causing this 'deformity'. In the second 'test', I found the lid to be 'deformed' in the same way. However, I did notice that as I moved the ruler further back toward the rear/bottom of the display that the 'deformity' became considerably less pronounced ? almost to the point of where the screen housing appears to be perfectly flat.

"So now the theories: Is it possible that the aluminum screen housing was manufactured with this 'concave feature' intentionally so as to keep the screen from touching the key tops and marking the screen (as was the case with the Lombard G3)? Is there some sort of 'stiffening device' built into the lid to force it into this 'concave shape'? Is the latch mechanism forcing this deformity? In any of these cases, is this 'deformity' placing pressure on the back of the screen and causing the white spots to appear as they would if you were to place pressure in the back of your screen with your finger tips? I've posted a link to photos of these measurements here: http://members.rogers.com/focusthis/"

Meanwhile, the UK Sunday Times notes that its evaluation PowerBook G4 15" (FireWire 800) unit is displaying the white spot problem: "A recent refresh of Apple's pristine PowerBooks has blessed this 15in model with tricks previously reserved for its more sizeable sibling, including the swish keyboard that automatically illuminates in dark surroundings. Such aesthetic wizardry is Apple's forte, but performance is not neglected either, with this laptop tearing through demanding multimedia, ably assisted by friendly software. The screen on the review model showed bleached-out blotches, though this is likely a one-off, and while the laptop is thin, it still weighs a portly 2.5kg."

UPDATE: More confirmation of delays MacFixIt reader Stewart provides more confirmation that Apple is delaying shipment of some PowerBook G4 15" (FireWire 800) units:

"I live in Toronto, Canda, and I was in an Apple reseller (North Star Computers) on Saturday just passed. It indeed seems that Apple are delaying orders. I overheard a conversation between one of the sales people and an interested customer looking at the 15" (it is a small Apple reseller and the staff are quite knowledgeable). The sales person said that there was a delay in 15" PowerBook orders and he stated the screen defects as the reason."

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