Need help moving hard drive from old G4 tower


macrumors member
Original poster
Jun 19, 2002
I need to move a factory installed 20 GB hard drive from a 400Mhz Power Mac G4(AGP graphics) to a Dual 1 Ghz G4 becuase evidently the motherboard is bad in the old comp. I've never installed another hard drive before so I was wondering what problems I'm likely to run into? Both of the hard drives are startup disks so will that cause a conflict? Any easy instructions for doing this on the internet that I could print out? I really need to install it to retrieve data but after I get that would it be worth it to keep it around in my comp or is the hard drive to old to be worth it?
Sorry for the newbie questions but I don't want to hurt my comp cause its my baby! Thanks for to anybody that reads this and replies.


macrumors 68000
Dec 4, 2002
My house!
Its actually very simple to do what you've requested.

All you have to do is pull the latch on the side of the PowerMac (old) which will drop the side down. Then pull the IDE cable off, which is the wide gray cable. This is the cable that transfers the data back and forth from the hard drive itself into the IDE Connector on the logicboard (Apple's name for the motherboard) and then to where it needs to go. Then pull off the power connector which is the smaller connector with 4 wires. There's probably 4 screws, 2 on each side of the hard drive that hold it in the hard drive bay. Take those 4 screws out and the drive should slide out.

Now on the new PowerMac:

Pull the latch on the side of it, which also drops the side down. There are 4 internal bays that will hold a hard drive. Choose the bay that best suits the room you have with the cable length, etc. Put the 4 screws into the sides of the hard drive to hold it in place, and then plug the IDE connector back into the hard drive and then the power connector. Both plugs only go in one way. Each is keyed so that it does only go in one way, so if it goes in really hard, make sure its going in the correct way. Try not to bend the pins on the hard drive when plugging in the IDE connector. If you do VERY CAREFULLY take a flathead screw drive and straighten them out. GENTLY!!!!

If they break, you can kiss your 20 GB hard drive bye bye!!!!

If this is going to be the main hard drive that you will use to boot the computer from then there's really nothing else you need to do since you're in a Mac. If you were on a PC, you'd have to perform a repair of Windows so that it re-adds the different hardware, etc... With Macs, this isn't a problem. Everything should auto-detect and install. The only things you may have to install is specialty cards that you've added and required special drivers, printers, and things like that. Other than that, you're all set.

If you're going be using this drive as a secondary hard drive (aka slave) on the same channel then you need to change the jumper on the hard drive from Master to Slave. How to do that all depends on the manufacturer of the hard drive. Most label exactly how to do it right on the drive. Getting the jumper position wrong won't hurt the drive nor the logicboard in any way. It just won't show up in the Finder, or in Drive Utility (Disk First Aid if using OS 9 and below).

What I mean by a secondary hard drive on the same channel is that there are usually 2 connectors on 1 IDE cable. The end connector is considered Master and the one below it is considered slave. So the first hard drive connected to the IDE cable should be jumpered as Master, and the hard drive connected to the 2nd IDE connector on the cable should be jumpered as slave. The same theory goes for connecting more and one CD, DVD, CDRW, or DVD RW drive to an IDE Connector. Yes, you can mix and match different IDE Devices on one cable. So for example you can connect the hard drive and CDRW Drive on the same IDE Cable no problem. Just make sure you jumper the Hard Drive as Master if its on the end connector and the CDRW Drive as slave if using the 2nd connector. Usually its best to have the hard drive as master and CDRW drive as slave if you have, or are making that configuration.

So where are the jumpers? The jumpers are located in between the IDE connector and the power connector. Its a little rectangle type plastic thingy that has two holes on the end of it. Inside it is a wire that goes from one side to the other. The actual jumper can be many different colors. I've seen Black (most common), white, blue, green, red, yellow, and even brown colored jumpers. Again, the position of the jumper depends on the manufacturer of the hard drive. question is a stupid question. Thats what forums are for, to help people out when they are in need, no matter how dumb the problem may seem. I was where you were at one point too.

If you have any other questions or problems changing the drive, please feel free to post you're question, or problem.


macrumors regular
mklos said:
Its actually very simple to do what you've requested.
and yet you wrote how many pages?... just messing ;) couldn't have given a more detailed set of instructions myself... I would have had trouble disciplining myself to write that much! I guess I'm lazy.

Couple of comments however... as long as you've set the jumpers correctly it SHOULDN'T (not to say that it won't) matter which drive is connected where on the cable. The drive positioning should only be critical when the drives are set to Cable Select (CS). Also, since the 400Mhz G4 is about the same age as my iMac I'd venture to say that your drive is probably a Maxtor. If it is even more like mine then it may use more than one jumper to set Master/Slave. If so you can look up such settings on Maxtor's support website by using either the serial number... or is it some other number... on the hard drive's label sticker

Good Luck!