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iMac G3 2001 issue with "modern" slim DVD-RW

indibil

Well-known member
Hello! I need your help.

I have an iMac G3 500@650MHz with OS 9.2.2. The original optical drive struggles to read discs, so I've adapted an original ATA slot-in laptop DVD-RW unit from a Mac Mini G4. I had the DVD holder from an iMac G5 and with it added on top of the original iMac holder, I managed to fit it into the slot in the case, and with a 50-40 pin ATA adapter I connected it along with an SSD. The drive works perfectly, it reads both CDs and DVDs, I just need to try recording, but that's not the problem.

The problem is that the Firmware of the equipment does not recognize this optical drive as bootable, no installation disk boots either by pressing C or by pressing the ALT key. This already happened to me years ago, with my first G4, it was a Gigabit Ethernet with a DVD drive, which I replaced with an HP CD-RW, which worked great, but did not allow booting from any disk.

Is there a way to "modify" the iMac Firmware so that it recognizes the drive as bootable? This reader allows to boot without problems in the Mini G4.

Thank you!!
 

Byrd

Well-known member
Welcome indibil,

There is no firmware hack to do this - Apple either supported the drive or it didn't. Some you could mount discs on desktop as you've done (but no booting) but if the initial boot support isn't there I'd suggest trying another brand of slimline drive. They're cheap enough to grab a few and test. Apple used Panasonic branded slot-load drives in later models, UJ-8xx models.
 

BustedCap97

Well-known member
just take apart the original drive, and clean the laser, and adjust its strength. there should be a potentiometer to adjust the laser. older drives sometimes need a stronger adjustment
 

indibil

Well-known member
Thanks for answering.

They are cheap but I have bought a couple of units and they do not work very well, users have given them a lot of trouble. If they were SATA, they are easy to find, but ATA... In Spain it costs a bit.

I have managed to get it to boot from DVD, from within OS 9.2.2, in the BOOT panel, I select the DVD and then when I restart it does boot. The problem is when there is no OS installed. The drive I installed is the original one from a Mac Mini G4, but from 2005, the iMac is from 2001, Apple couldn't "add" it into the firmware.

I have the original unit stored with all the original parts, I'm not going to manipulate it for now, but the new unit gives me support for DVDs, a fact that the original did not give me.
 
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Cory5412

Daring Pioneer of the Future
Staff member
One alternative option: Does your iMac already have a working Mac OS 9 installation on it? If so, you may be able to copy the files from that installation onto USB media that's under ~200 gigs and boot from that.

OS X may require firewire, unfortunately. (I keep meaning to try this on my own slotload iMac but haven't had time to yet.)
 

BustedCap97

Well-known member
I seem to have the opposite problem: My optical drive reads discs just fine, but it cannot eject them and has a really hard time inserting them. its like the mechanism that handles the disc is just slipping and not gripping very well.
 

MacUp72

Well-known member
"I managed to fit it into the slot in the case, and with a 50-40 pin ATA adapter I connected it along with an SSD."

maybe that 50-40 pin adapter is the cause of it nor being recognized as master. Apple branded drives have a master/slave pin, maybe that helps:
 

indibil

Well-known member
"I managed to fit it into the slot in the case, and with a 50-40 pin ATA adapter I connected it along with an SSD."

maybe that 50-40 pin adapter is the cause of it nor being recognized as master. Apple branded drives have a master/slave pin, maybe that helps:
Hello! Thanks for the reply.
My 40IDE to SlimIDE adapter does not have a MASTER/SLAVE selector, but I solved the connection using an ULTRA-ATA100 cable, because each connector is specific for Master or Slave. In the blue one I eliminated the guide to be able to connect it to the motherboard, I connected the black one to the hard disk (master) and the gray one to the DVD-ROM (slave).
The iMac G3 Slot loader only has one IDE port, and both devices are connected to it.
 

MacUp72

Well-known member
My PowerBook 1400 did just not boot until the CD was master. I think your our G3 iMac has a somewhat better/little more modern IDE implementation but this is crucial. I would disconnect every drive and start with only one cable , and then from there..
Have you some fotos of your connections/cables?
 

indibil

Well-known member
Thanks, I'll have to open up to take some pictures.

I don't think the problem is in the MASTER/SLAVE setting. If from Mac OS 9 or OS X I select in "boot disk" the CD drive, when restarting it boots from CD without problem. I can't boot from CD by pressing "C" on the keyboard, or the "ALT" menu when booting.

As I said, this already happened to me years ago with a Gigabyte G4, which when changing the factory DVD-ROM for an HP CD-RW, did not recognize it as a bootable device by Open Firmware.

These are factory limitations of the Open Firmware, some devices are not compatible.
 
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