iMac G4 Flat Panel Won't Recognize Drives

[pvolkmann]

I recently acquired an iMac G4 Flat Panel that will not boot. When turned on, you can hear the hard drive spin then stop, then the DVD combo drive spin and stop. I cannot get this G4 to recognize either drive. I can't eject the disc in the dvd combo by any means other than the manual eject lever inside the access door. All I get is the folder with the face/question mark. Things I've tried:

1) Reset the PRAM.

2) Checked the backup battery.

3) Checked all drive connections.

4) Gone into Open Firmware and tried several command combinations; reset-nvram and reset-all.

5) Reset the PMU using the reset button on the logic board.

Any ideas? I'm hoping it's not a bad logic board. Thanks.

 

[joshc]

Power on the iMac, with a good known-working startup disc inserted, and hold Option. Wait, and a screen should appear showing the bootable options. When you can hear the hard drive and optical drive making noises during startup, it is looking for a bootable OS but not finding anything. If you cannot boot from a CD/DVD, then try an external Firewire drive with an OS 9/OS X install instead.

 

[pvolkmann]

Thanks, Wackymacs, but I tried that, too. I get the screen with the refresh button on the left and the arrow button on the right, but no drives appear (with a good OS9 install disk in the DVD combo drive). Don't have any firewire backup devices. I do have USB external hard drives. Anyone ever boot through the USB port?

 

[joshc]

You should be able to boot from a USB drive, as long as there is a known working OS 9 or OS X install on that drive. You will have to hold Option at boot with the drive connected. Let me know if you have any success with this method.

 

[~Coxy]

Some PPC Macs are very finicky about USB booting. They won't work at all, or require you to drop into Open Firmware to force it to try USB.

 

[pvolkmann]

Well. ~Coxy, you were correct. I tried a USB hard drive, zip drive, and CD drive. No Luck. The Mac would see only the USB CD drive, but would not start the disk. I tried OS 8.1, 9.2 and 10.4.11 install disks, but none would boot. As the internal DVD combo won't even open using Command-E or via the keyboard, I'm afraid the problem is with the logic board.

You mentioned forcing the Mac to read the USB through Open Firmware. What would the command be for that?

 

[~Coxy]

I think it was boot-usb? I was actually talking about it to a friend saturday night, he couldn't remember the exact command but he remember his issue well. Two iBook G4s, one could boot and one could not from the same USB DVD.

 

[tyrannis]

Using the "set-defaults" command with resets seemed to bring the FireWire back on a 12" G4 867 MHz for me. It was having a similar problem recognizing drives at the volume select screen.

 

[sevenbegore]

I had this exact problem not but a month ago. Something about this particular iMac i guess. Nothing I did worked. I tried every trick I could find: booting from various install CDs, starting up in single user mode, dismantling the thing and putting a new hard drive in it. Nothing at all worked. What I finally did was I took the original hard drive out of it and hooked it to another working mac i have with a USB IDE drive adapter and ran a disk repair on it from there. After that it booted, no problem. Go figure.

 

[Christopher]

What model iMac G4 is this?

I put in my 700MHz iMac G4 a pioneer that was in my early model LaCie D2(non dual layer) and it worked just fine.

 

[pvolkmann]

I finally got my iMac G4 up and running. I installed 9.2.2 on a USB external hard drive via my G3. Starting up the G4 with the button pressed, the G4 did recognize the USB hard drive, and the DVD combo drive still would not operate, so I opened up the case (as many of you may know, there's a lot packed into that small dome). I removed and tested the hard drive, and it would not respond. I removed the hard drive with the good OS install from the USB external case and installed it into the G4. When I fired up the G4 it started right up, and the DVD combo worked as well. Apparently whatever happened to the hard drive effected the operation of the hard drive, no idea why. Thanks to all for your suggestions. I have found that a G3 and a G4 will boot off of USB device with an operating system properly installed.

 

[phreakout]

Sounds to me that maybe the jumper settings on the hard drive and the optical drive needed to be checked. IIRC, both drives are linked to the same IDE cable. Therefore, you could try and make sure that both drives are set to either "Cable Select" or "Master/Slave" combination. Remember, on those cables, the connector farthest away from the one that attaches to the logic board is considered Drive 0 or Master, and the one in the middle is Drive 1 or Slave. Try these suggestions and give a report back to the command post, soldier.

73s de Phreakout. b-)