My rev A iMac tries to start, chimes, spins up the hard disk, then turns itself off about 3 seconds later, before the screen can display anything. Then pressing the start button has no effect unless some time has gone by. I am in N. Mindanao, Philippines, about 500 mi from a service center and usually have to depend on myself to fix computer or monitor problems. I've dismantled the iMac, eyeballed and cleaned all the cards and connectors, removed my iProTV card, but it still exhibits the same behavior. I'm about out of ideas. Anybody out there with similar experience or some technical insight? What is the startup sequence the machine goes through as it comes up?

[WDL]

Try these quick, simple steps:

1. While shut down, unplug ALL your USB devices including the keyboard/mouse. Startup using the button on the iMac. If it completes a normal start up, plug in the keyboard/mouse.

2. Now, go to the Startup Disk Control Panel and make sure your HD is selected as the startup disk.

3. Then go to the Startup Items Folder, inside the System folder - open it and remove any items that may be in it.

4. Go to the Energy Control Panel and ensure all the settings are set to "Never" - Sleep, Shutdown etc.

5. Disable Norton File Saver and any virus protection (in case you have any of these installed).

6. Now try a Restart from the Special menu.

If the startup completes normally, then shutdown and plug in one USB device and startup. Keep doing this, adding one more USB device each time to see which, if any might be causing a problem.

I doubt very much that you have any kind of a hardware problem - it's most likely software, and most likely a USB conflict between 3rd party software and the USB drivers built into the system ROM. These conflicts are causing all kinds of instability and strange behaviour that you would not expect to be related.

Would appreciate knowing if this proves successful.

WDL

[WDL]

Forgot to add:

If there ever was anyone who needed a good disk repair utility, it has to be you, considering you are 500 miles from the nearest service centre.

By all means, get:

TechTool Pro 3 - Micromat

and

DiskWarrior 2.0.2 with Plus Optimizer - Alsoft.

If you can afford ony one - TechTool Pro.

WDL

Thanks for your reply. It's all very good advice, but unfortunately my problem seems to be more fundamental. The machine does not actually startup or even get to the point of lighting up the screen... It only chimes, spins up the disk then immediately powers down, all in the space of three seconds or less.

Right now everything is disconnected from it, it's on my desk without its skin and I've gone over it and resoldered any connections on the power supply card that looked the least questionable. I've also removed the upgrade memory SIMM. It's behavior is quite consistent, but it's puzzling that it requires a 'rest' period before it will even power on in response to the startup button.

Incidentally, I do use TechTool and had just upgraded to 2.5.5 and run it before the problem ocurred, but I don't think TT is related to the problem. The computer had just started getting a little flakey before that, and the screen occasionally flickered. I have not given the video card the same kind of attention I have the power supply card. Is it possible the machine detects some kind of failure in the video card and aborts the startup sequence?

[This message has been edited by edsford (edited 08-13-2000).]

[roders]

I've had a prob like this in the past, with my Lacie CDRW when I updated Toast, which updated the USB CDRW extensions which caused the same symptoms on my iMac, so are you sure this is not USB related?

P.S I guess you haven't got AppleCare?
(they will/should pick up your machine for you)
Sorry I can't be of more help.

[This message has been edited by roders (edited 08-13-2000).]

[WDL]

If your Mac won't startup from the OS install CD, then I'm at a loss.

I'm so very sorry I don't have the knowledge required to assist you further.

If, by some means you do manage to boot up, the very first thing I would do is disable the USB extensions. I still feel that USB is somehow at the heart of your problem(s).

One last far-out possibility - others on the boards have been reporting that their startup button is not moving in/out freely, and that when they use it, it won't come back out - it catches on the edge of its enclosure.

Can one hope this is the simple solution? What if!!!!!!

Please let us know the outcome/status.

WDL

I was able to contact DPSI, the official Mac service center in the Philippines, and asked if I shipped the electronics (Power Board, Analog Board and the complete tray), could they diagnose it and let me buy the part(s) needed. They were very helpful and noted that there were cases with similar symptoms caused by a problem on the Analog Board. I'll post the final outcome before closing this topic.

[Rave]

I had the same problem, the IDE cable had worked loose from the CD-Rom Drive (what can I say, I've got kids ).
I'd open that puppy, and just be sure all your connections are tight.

Peace

The DPSI folks diagnosed it and say it has a leaking capacitor on the Power Supply Board and the Analog Board was also damaged, possibly because of the power supply problem. The Analog Board has to be replaced, but they have been trying to locate a replacement for the big capacitor on the Power Supply Board. Replacing both boards would be a little pricey. Does anyone know a good source for the less common components that appear on the iMac boards?

[This message has been edited by edsford (edited 08-25-2000).]