An iMac and a Black Screen
May 29, 2007 | 7 Comments
I recently purchased a 20″ Intel-based iMac from Apple. I did not purchase it for myself, but for my niece. I happen to live in the same household, so I perform all security related updates on the system. I’m basically her in-house System Administrator. However, lately she has begun to complain about being unable to use her computer.
Observations:
The computer turns on without any noticeable problems, but then all of a sudden the screen goes dark (i.e., it turns pitch black). Thereafter, the computer does not recognize any keyboard or mouse input. On some occasions it makes a noise as if trying to eject a disc from the CD/DVD-RW drive. Upon closer inspection, you can faintly hear a fan spinning inside, but the power LED does not flash to indicate that the computer is in sleep mode.
If you press and hold the power button for a few seconds, the computer makes a sound; a single click as it turns off. Subsequently, all mechanical activity ceases and you can no longer hear any noises coming from the unit.
The difference between sleep mode and the aforementioned is that the power LED does not light up and blink every other second. Instead the Power LED remains off. However, this may vary. Today after restarting the computer a few times the power LED remained lit. The login screen failed to appear and the screen remained black. Also, the usual startup chime could not be heard as the computer was powered on multiple times. Other times the computer restarts on its own. Afterwards, the screen goes dark within a few minutes. Transporting the computer from one location to another and connecting it to a power source, may sometimes cause it to turn on by itself. If the computer is allowed to rest for a few minutes, then it works properly for a short duration.
On another occasion the system simply froze and displayed several multi-colored vertical lines on the screen. Nothing could be done to bring the system out of its frozen state besides performing a forced shut down.
Images:
Frequency of Occurence:
Intermittent. Usually the computer cannot remain in a usable state beyond 2 consecutive days. However, once the screen goes dark (turns black) the frequency of occurrence dramatically increases. Thereafter, you may experience the above problems every few minutes; sometimes seconds.
Duplication:
Yes.
Possible Causes:
Malfunctioning logic board
Improperly seated memory
Improperly seated video card
Malfunctioning hard drive
Attempts at Resolving the Problem:
Repaired/Verified the disk by using the disk utility from Mac OS X Install Disc 1.
Repaired/Verified disk permissions by using the disk utility from Mac OS X Install Disc 1.
Performed a hardware test by using Mac OS X Install Disc 1.
Test Results: No trouble found
Configured the Energy Saver settings to extend the amount of time before the system goes into sleep mode.
Performed a reset of PRAM and NVRAM.
Performed a reset of the System Management Controller (SMC).
Reseated the memory modules.
Reinstalled the operating system.
Hardware Overview:
Machine Model: iMac5,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.16 GHz
Memory: 1 GB
Boot ROM Version: IM51.0090.B08
SMC Version: 1.9f4
Chipset Model: ATY,RadeonX1600
VRAM (Total): 256 MB
ROM Revision: 113-xxxxxx-139
EFI Driver Version: 01.00.139
Wireless keyboard and mouse with fully charged batteries.
System Software Overview:
System Version: Mac OS X 10.4.9 (8P2137)
Kernel Version: Darwin 8.9.1
Boot Volume: Macintosh HD
Comments:
I am really starting to get very disappointed and frustrated with Apple hardware products. Throughout the last decade I have been a strong advocate for the company’s products. I have encouraged a countless number of people to purchase Macs of all sizes, shapes, and forms. All my friends and close associates even think that I should go and apply for a job at the company. However, I am starting to have second thoughts about the company’s commitment to quality. Next month, I will not be purchasing a 1st generation iPhone as originally planned. It is not the lack of available features or even the expensive price tag, but a lack in confidence on my part in the quality of Apple’s latest products.
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