iMac 4,1 (early 2006) stops reading HDD

Discussion in 'iMac' started by giorgio.hacks, May 11, 2014.

  1. giorgio.hacks macrumors newbie

    Sep 20, 2008
    Cordoba, Argentina
    Hello everyone. I'm having trouble with an iMac I have in my house which I'm trying to repair so that I can sell it. Let me explain the context:

    I received this iMac about a few months ago from a friend. He had asked me to add more RAM and sell it.

    The iMac is the early 2006, 20 inch, Intel Core Duo version. I had Leopard installed and 1GB of RAM (2 x 512MB).

    My friend wanted me to add 1GB more of RAM so I purchased 2 x 1GB SODIMMs compatible with this iMac. I installed the RAM and at the same time, reinstalled Leopard. When I booted it up with new RAM and new OS installed, it would work for a few seconds and then it would freeze completely. It was like if the computer had stopped reading the hard drive.

    Immediately I thought it was the RAM since it was the only hardware change I had done. I talked to the seller and he told me that it was his own personal memory and that it worked fine so I burned a copy of memtest86 and ran it a few hours completing many cycles. I didn't get any errors so I ran it a complete day looking for at least one but nothing showed up.

    I then swapped the RAM for the old one which I was sure worked and nothing, the same problem, a freeze about 20 seconds - 5 minutes from booting. I then thought it was the internal 250GB hard drive.

    I took the Mac apart and removed the hard drive and replaced it for one I had which I was sure worked. Installed the OS and it wouldn't even install. When I had to select which drive to install the OS, sometimes the drive would disappear like if there where nothing inside. I ran HD Tune + on the original HDD and no errors popped up. I ran it in my drive and no problems once more. At this point, I was about to remove hardware from the list of possible problems but I ran Disk Warrior 4.4 and here I had more problems.

    When I inserted the Disk Warrior disc, it would sometimes boot from it and other times just spit it out. When it did boot, I would perform a function to repair the drive (I'm not sure what the function was, something like permissions or disk repair or something, whatever, not important). However, when I did this, it worked fine for a while and then it stopped recognising the drive (just like the OS X installer did) so there I got very confused and couldn't think what would cause this problem.

    Today, I have the Mac with Leopard installed but won't work and Disk Warrior won't boot and I don't have anymore resources for trying things on it. The installation of Snow Leopard (yes, I tried installing it a few times in the middle) would always die at the same point, telling me some files couldn't be read or copied or something like that (this is how I jumped to the conclusion that the HDD might be the problem).

    For the record, both Leopard and Snow Leopard where installed from an external Hard Drive but I don't think it's a problem, I've read I can do this with no problems.

    Anyways, I would be really happy if anyone would share a tip or piece of data that might help me get done with this machine. It's been 6 months since I have it in my hands and I just want to finish with it.

    Thanks everyone for taking the time to read this and if you have anything that might help me, I'd be very glad.
  2. FreemanW macrumors 6502

    Sep 10, 2012
    The Real Northern California
    Sounds to me as though this piece of technology is ready for its dirt nap.

    I would venture that a new hard disk drive may get the parade off the dime . . . . but the cost of the new hdd coupled with the time and labor to install it has just placed any potential profit in jeopardy.

    Then again, there may be another piece of electronics that is in or on its way into failure mode.

    See eBay for prices.
  3. giorgio.hacks thread starter macrumors newbie

    Sep 20, 2008
    Cordoba, Argentina
    Thanks for your advice. I guess I'll have to buy a new hard drive. I did already try this with a different hard drive I had laying around but maybe it wasn't any good. I'll buy a new one and try this solution but in the mean time, if anybody has another idea, it would be much appreciated.
  4. TheBSDGuy macrumors 6502

    Jan 24, 2012
    It's probably the hard drive or a SATA cable in the unit, but before throwing money at parts or more test software you might try, if you haven't already, the following resets:

    That's for the NVRAM and the SMC. I doubt that's your problem because usually it wouldn't even recognize the drive, however it may have some of the drive parameters mixed up or lost. If it's the unit I think it is, it has an on-board battery that helps retain information and after 8 years, odds of it being shot are probably pretty good. Here'a link to how to fix it, assuming I have your model number right:

    The only thing that I know that can effectively tests both drives and cables as well as the system bus is Scannerz:

    but at this point I'd be worried about cost, and that's 40 bucks.

    You might want to check the going prices on eBay because you could easily end up probably spending more on the unit to get it up and running than it will sell for in working condition. A new HD is likely going to run $60 or more and if the systems are only selling for, say $150, and you have to put all the labor in to fix it, is it worth it?

    If it was me, I'd try to find another Intel unit running Snow Leopard, Lion, or maybe even Tiger, put it into target disk mode and then try to boot the iMac from that. This way you could test to see if the unit works properly without even needing the internal drive. It's probably the drive but without testing it you won't know, and if you just throw new parts at it and it turns out it's the logic board both money and time will be wasted.
  5. MacRobert10 macrumors 6502

    Nov 24, 2012
    I didn't even know these things had batteries in them!:confused:

    If the battery goes down or starts dying, does anyone know what the symptoms are?

    Are they in laptops too?
  6. giorgio.hacks thread starter macrumors newbie

    Sep 20, 2008
    Cordoba, Argentina
    Thank you "TheBSDGuy". I will try the thing you told me about the internal battery. Then I'll reset everything and if nothing works, I'll try running that piece of software you recommended. I'll post again with results.
  7. giorgio.hacks thread starter macrumors newbie

    Sep 20, 2008
    Cordoba, Argentina

    Ok, so I did the battery change and NVRAM / PRAM reset and it seems to be working. I can't believe it was such a simple solution. I'm installing software updates and it's working and I could never reach this part without the computer freezing. I thought I was a very tech savvy person but this detail was very important for me to dismiss or overlook. I guess I didn't consider the age of the machine a problem since I've never dealt with machines older than 5 years.

    UPDATE: While I was writing this response, the installation process froze and I rebooted the machine. When it booted up, i got a kernel panic. Rebooted and the same. I'm guessing the OS files got corrupted by interrupting the installation. I'll try installing Snow Leopard now the I replaced the battery and hope it works. Here are a few pics of the errors. I'll update the story as it continues. Thanks for everyones help, it's much appreciated.



  8. ZVH macrumors 6502

    Apr 14, 2012
    If I had a result by that I'd be trying with an external drive at this point.

    If this is done on an external drive and all problems disappear you'll know what the source of the problem is. If you could even boot off another system in target disk mode with a compatible OS you might want to try that....just to make sure the logic board or power supply aren't the problem.

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