MacBook (#3): Sudden shutdowns -- possible fix; More on irritating noises; Hard drive replacement instructions

Sudden shutdowns -- possible fix Several readers have reported an issue where the MacBook will suddenly shut down and then refuse to boot again.

The issue might specifically affect owners who built-to-order their MacBooks with upgraded RAM.

The fix, in most cases, is to re-seat the RAM modules. For instructions on accessing the MacBook's RAM modules, see this Apple manual.

Try removing the RAM modules then firmly seating them back in place.

As described in Apple Knowledge Base document #303083:

"If the computer detects no SDRAM (Synchronous Dynamic Random Access Memory, also referred to as RAM) or the RAM installed does not meet the appropriate specifications, the screen will remain black but the power LED on the front of the computer will blink once per second to signal the error. This error condition may be due to physically damaged RAM, installing the incorrect type of RAM, or not having RAM installed."

More on irritating noises Meanwhile, users continue to comment on two distinct, irritating noises generated by the MacBook: a "mooing" noise that occurs when a specific fan spins up then down repeatedly (similar to the one exhibited by the MacBook Pro), and a high-pitched noise emanating from the power supply.

MacFixit reader Ian Brown writes:

'I recently purchased the new MacBook.  I let the battery totally discharge prior to charging it the first time.  I plugged in the power adapter to charge the battery and continued to use the MacBook, but I noticed a high pitch scream from the power adapter that changed pitch whenever the disk drive was accessed, presumably due to increase load.  The noise is reminiscent of old switch mode power supplies."

Mark O'Brien adds:

'I received my MacBook yesterday (2.0GHz, 120GB HD, 2GB RAM) and have exactly the same mooing sound. The video you linked to shows exactly what I'm hearing when the computer is sitting idle at my desk. Peak sound occurs about every 7 seconds. I'll download the Core Duo Temp app tonight and see what the readings are when the fan cycling occurs."

If you are experiencing a similar issue, please let us know.

Apple offers Do-it-yourself hard drive replacement instructions We previously noted that the MacBook's hard drive is easily replaceable, allowing addition of 7200 RPM drives (not an option at the Apple Store).

As noted by MacFixIt reader Rod, Apple has now posted some do-it-yourself instructions for replacing the hard drive.

Previous coverage:

• MacBook (#2): Irritating fan noises reminiscent of MacBook Pro ("mooing"); Matched RAM pairs can come from different manufacturers; more
• Apple releases MacBook: 13-inch widescreen display; up to 2 GHz Core Duo; integrated graphics; starts at $1099

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