2007 iMac errors on startup, but displays different symptoms.

[bagelche]

My work iMac is having serious problems at start up, but the symptoms keep changing, so I'm not sure what the culprit is.

Friday, I turned it on from sleep and it didn't wake up. Held down the power button to do a restart. After the startup chime, I got several beeps, suggesting a RAM problem. Restarted again, same result. Tried again and it went past the apple logo, then dropped to black and sounded like the optical drive was spinning up repeatedly. After power down/up it would do this behavior: black screen, drive spin up sound, pause, drive spin up sound.

That's where I left it and returned today. Power up gave the same black screen, drive spin up routine. Tried again and it immediate gave the startup chime and Apple logo, then white screen with cursor, which switched to spinning beach ball, then froze. Next start up with chime and logo all the way to the desktop.

The computer is clearly unstable, but I'm not sure where to approach a fix.

Thanks.

 

[bagelche]

Update:

Computer has been running OK since I posted that. I plugged in a Firewire drive to update my backup while everything was running. The computer immediately froze. Upon restart (x2) I get a single beep--meaning, I assume, it doesn't see any RAM installed.

I don't know why connecting a FW drive would trigger that.

 

[kpgh554]

Update:

Computer has been running OK since I posted that. I plugged in a Firewire drive to update my backup while everything was running. The computer immediately froze. Upon restart (x2) I get a single beep--meaning, I assume, it doesn't see any RAM installed.

I don't know why connecting a FW drive would trigger that.

have you got discs that came with comp if so run hardware test by inserting disc{1} hold alt+d at startup if ram or hd it might give idea which

 

[MacVibe]

A cavalry firewire 800 drive causes my imac to freeze, and this is repeatable. Exactly when it happens isn't repeatable but if left in for hours, or a day, it will freeze at some point. I replaced the drive inside the enclosure and the freeze problem continued. I think the enclosure is bad. This has been a very frustrating problem, especially after reading about how much better firewire is than usb. I'm getting a different firewire drive and will cross my fingers for no freezing.

 

[bagelche]

Thanks for the replies. My initial thought was RAM due to the beeps at startup, but the a) black screen, drive spin-up and b) FW connection crash confused me.

The computer had a 1GB and a 2GB chip in it. I pulled the 1GB and haven't had a problem since, through a couple of restarts.

I'm going with faulty RAM, but we'll give it a bit more time.

 

[MacVibe]

Glad you found it. You may want to run the apple hardware test at startup to see if there are any other problems, since this would be the first thing a genius would do if you took it in for service:

http://support.apple.com/kb/ht1509