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Troubleshooting the PowerBook G4 15" (FireWire 800): Seeing spots (part 3); Bad RAM

Troubleshooting the PowerBook G4 15" (FireWire 800): Seeing spots (part 3); Bad RAM

Seeing spots (part 3) Continuing our investigation of the PowerBook 15" (FireWire 800), yesterday's theories about some sort of physical pressure in the screen's housing seem to be gaining credence.

As a reader pointed out yesterday, "if you take your finger and drag it firm, but lightly across the center of the back of the screen, you will get ripples in the white spot areas."

We've now received another report from Hanford Merritt (the same user who originally sent the picture mapping the problem), noting that small pieces of foam within the screen backing are located near where the problem spots are showing up.

"On my 800MHz Titanium PowerBook G4, my screen broke and I replaced it with another I found on Ebay. I still have the old frame, and there are several foam supports glued onto the inside of the lid frame (which rests directly against the back of the LCD). They are approx. 1/16" high. and the strips are 5/8" wide (same width as most of these new marks). The pattern of the foam is not exactly similar to the marks on the new 15" Aluminum PowerBooks, but the foam is surrounding the Apple logo. I'm sure a similar system was used in the new 15", but may not have had enough room between the pieces to avoid the distortion."

Apple delaying orders to fix problem? Though a definite causation cannot be determined, Apple is delaying PowerBook G4 15" (FireWire 800) across the board. Nigel Glazebrook writes

"This may not be related, but I've recently ordered a 15" PowerBook from Apple Store UK and have just been informed that there will be an delay for delivery (see following e-mail). I was wondering if this was to give Apple a chance to examine all shipments and replace any of the lids or screens that are causing the problems (according to their tracking Web site, the laptop is currently in Luxembourg, and has been there since 11 October)."

Bad RAM We are receiving a surprisingly high number of "bad RAM" reports from PowerBook G4 15" (FireWire 800) owners after yesterday's postulation that the new PowerBooks might be especially sensitive to faulty memory.

MacFixIt reader George writes "I bought a 15" PowerBook G4 1.25 GHz from J and R in New York, and they agreed to match MacConnection's offer of a RAM upgrade. But, when I got the machine and installed the 2 512 MB cards, the machine would have kernel panics, and I would be forced to restart. I tried Apple's Hardware test CD 4 times, and everything came up clean. I called Apple, and read the logs to the tech support fellow, and it was determined that bad RAM was the cause of my problems. He suggested removing a card, and trying each card separately. I did so, and found that one card seemed to work fine, but my computer wouldn't even finish booting with the other. So, I sent the bad RAM (made by PNY) back to J and R, and ordered a new one from Crucial."

As stated earlier this week, sometimes RAM that appears fine to Hardware Test is still defective. This is rare, but it certainly does happen. The most foolproof way to figure out if bad RAM is a cause of problems is of course to remove RAM (replacing it with known good RAM, if necessary) and see if the problem goes away. That being said, the Hardware Test CD is a quick and easy "first step" to take.

Unfortunately, it appears that Apple semi-frequently ships Macs with at least somewhat defective RAM modules. Apple does not disclose its component suppliers.

Meanwhile, some RAM suppliers are blaming the problem on misinformation from Apple. One reader received this response from reseller OWC:

"We have discovered what has been plaguing the Memory world on the new Aluminum 15" and 17" PowerBooks. It seems Apple failed to express a set of code that was needed on the memory chips for the new Aluminum 15" and 17" PowerBooks. Apple has since revealed what was missing and we have had a new batch of memory Specially designed for the Aluminum 15" and 17". It normally costs more than the memory you purchased but I can upgrade you at no additional cost and ship it our right away. Please let me know if you want this new High Performance Memory for your PowerBooks."

The safest course of action is to order memory from a reputable, established manufacturer, to which you will be able to return a faulty module.

Feedback? Late-breakers@macfixit.com.

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