I recently had to tear apart a Lacie external harddrive to figure out why it had failed. Fortunately it wasn’t all too hard, but I could not find any other websites really supporting this particular approach I needed. In this guide I will mainly outline the process to diagnose for a faulty power supply, but will also  touch up on complete disassembly and what to do if it should be some other common problem.

*Follow this guide at your own risk. I will not be held responsible for failed repairs using this guide. You perform these actions at your own risk. If you feel uncomfortable doing so then seek out another party to service it for you.*

*Updated 10/28/2010: Blue wire in my case was 12v. Always double check with a multimeter, as similar models may be different*

Lacie Case

The problem maker itself

One thing I assumed when I had first started diagnosing the unit was the fact that it was a harddrive that had failed. I was wrong. I even tore apart the entire unit (which I will go into detail on later if you need to get inside) to find the source before I had reconsidered the problem origin. Before you even do anything, look for the following symptoms:

  • You hear the harddrives spin up, but immediately spin down, repeated.
  • No hard drive spin up noise /w just the blue LED lighting up.
  • The AC adapter generating a clicking or fairly audible buzzing noise. Don’t mistake this noise for the hard drives! Listen closely.

If any of those fit, chances are you’re in need of a new power supply. However getting one can be quite a hassle and many people often *need* the data off quickly rather than going through a long bureaucratic process if warranty still applies or if you are looking to get a replacement shipped. Here’s what I call the ‘Mike Method’ way of getting it done:

AC Adapter Fix (Mike Method)

First lets take a look at the AC Adapter specifications because were going to need to tear it apart and provide a power source similar to what it provides.

Lacie AC Adapter

Note the handy pin out. Pin 1 being the one clockwise from the nub along the outer rim.

If this is fried, there is no use for this, however the goal here is to cut the cable, which goes from this to the Lacie drive, and provide a source of 12v and 5v from the end of which the Adapter used to reside. Take the cable that comes out of this adapter (that goes towards the harddrive) and cut it. Make sure this adapter is not plugged in. You’ll want to cut it close to the adapter. Once done, strip the end and separate the three wires inside. I had blue, red, and black. IIRC, blue is 5v, and the red is 12v. You can SHOULD double check the wires by testing with a multimeter by checking resistance from the pins to the ends of the cables to determine the voltage of each wire. Swapping 5 and 12v supplies on a harddrive will toast it.

To provide power, I bet most of us are reading this on a desktop, why not use the PSU which fortunately provides voltages at 12 and 5? A common/cheap part is a Molex splitter. Any computer repair shop or computer store should sell these for cheap. There are many other molex cables that will work, so long as you have a female molex connector you can make it work. I used a cable that went from a larger molex connector to a single connector for a floppy drive. Basically you’re looking for something of this sort with a female end. That female end will be grafted onto the end of the harddrive power cord.

Molex Splitter

Molex Splitter

Cut off the male end (again, leave lots of cable on the female end to work with). If you end up using the splitter, you will have two sets of wires, one is not needed so snip them off or just tie the same colours together at the end. It’s time to match up the two cables! Use the chart below. Because the Molex has four cables, and the ac adapter only has three, on the Molex side, put both grounds together. Once complete, open your computer case, and simply connect it to any spare Male molex connector. Make sure there are no shorts in your wiring before doing so! It’s best to power down the system before connecting the Molex.

AC Adapter Cable Molex Cable
Blue(5v) Red(5v)
Red(12v) Yellow(12v)
Black (Gnd) Black (Gnd) (Merge both together)

Finished product!

In use, and the Lacie HDD fired back up.

If the problem is not with the AC Adapter, and you need to open it up, follow the below guide:

Lacie Big Disk Disassembly

Quite straight forward, heres a quick picture by picture play of how it’s done.

On the rear there are two screws, one on the bottom and one under the Warranty seal.
If you’re feeling sneaky, just rotate the plate counter-clockwise once the bottom screw is off to avoid the seal.

Then slide out the unit, face first.

Here’s the insides. To start removal of the harddrives flip it over and remove the mounting screws

Remove the six screws to dislodge the drives.

Disconnect the power and IDE cables. They are free! If you need to remove the controller board, they are simple:

Remove the two upper screws, and lift straight up.

Remove the single screw for the power board, and it’ll slide out away from the faceplate.

For your reference, Pin 1 is towards the USB connector. I had disconnected this and it had no visible markings to determine the correct way.

Additional Troubleshooting Questions:

Harddrive Failure: There is one other problem I can see happening to most other people. A harddrive failure. If one of the harddrives go down, chances are all your data is lost. This particular external harddrive stores data in a RAID-0 form. Meaning half the data is stored on one drive and half on the other. This doesn’t mean one file on one side, and another file completely on the other. It means a single file likely exists 50% on either side. So if a complete failure happens, you’ll  have to find some way to revive the fallen drive.

Component Failure: If the controller board is shot, but the harddrives are fine. The easiest solution would be to swap the drives into another working unit and copy the data off. If you can find a similar unit online, I would order one. You can’t just plop these drives into a desktop (even if it supports IDE raid). The controller on the desktop is different than the one in the external case and won’t recognize the RAID specifications. It is doable, but the only way I can think of would be to purchase RAID rebuilding software and a quick glance at some on Google reveal prices around $100. Since I have not gone through such an experience I can’t help much on what is best. Just know that there is still hope if this is the case!

Additional Resources: *new!*



  • Mike… Thanks for putting up this information. I have had my Lacie 1TB Big Disk Extreme go through three power bricks, and now I can’t get anything out of it at all. I did what you suggested even before I read this… I bought an identical working drive on eBay and I intend to swap the drives when it arrives later this week to see if I can somehow recover my “lost” data which included my time machine files as well as tons of photos. My drive is still under warranty, but Lacie won’t pay for data recovery but recommended a service they endorse… he wanted $600 and he said that was because he had to recover from two drives at $300 each…. said that many services would charge double.

    I’ll let you know how I make out.


  • Good luck with the recovery. I wonder how much of the profit model for Lacie comes from repair work ^^. You could for now, if you want to out of curiosity, open her up and just see if both drives power on to have some idea of what the problem is. Unfortunately I can’t see too many cases where its NOT the harddrive as there are no moving parts elsewhere. If one of the HDDs did bomb mechanically, then I can understand the cost. Sometimes, $600 is worth the loss in data, however it can never be guaranteed you will get it back. I’m Looking forward to positive results!

  • I Have 2 Lacie BigDisk 320Go.
    I had a failure of power o the 2 disk after 2 years use and i use an identical solution to repair and all is now working.
    Symtomes was:
    Blue led fix during power on and after
    The wheel drive dont run( no noise) but the head was “cliquing” at about 1 per secod
    With voltmeter i measure 14 V an 4.8 volt.With oscilloscope, the 5V and 12V was noisy (200mv noise) and each second the the signal had a down spike of about 2 V for the 12V and 1V for 5 Volts.
    The 2 Diskk are working now and i dont lost any data
    Sorry my english is not so good.

  • @Jacques: Thanks for the additional troubleshooting information! Its nice to see voltmeter/oscilloscope readings being used for this. I jumped a bit to the the conclusion (not always a good thing) after reading many people’s reviews of the product having a failed power supply. That, and the fact that the harddrive’s spun up fine when attached to a working power source.

  • @ Administrator:
    In fact I am not completely sure its a problem of power supply. I explain. The power supply is very noisy so the LACIE card include 2 filtering capacitors on the 5v and 12v. perhasps capacitors lost their performance with the time because its large capacitors in a very compact size (470uF).
    So with another Power supply like PC wich is less noisy the Lacie BigDisk work correctly.
    To day i have no time to test and replace the Capacitors, my disks are strategics and as its works i stop my investigations.
    Best regards

  • Hi guys and many thanks for the info.

    I have a dead/dormant (spins up partly, no light, refuses to mount) 1TB LaCie external drive, and was about to try remapping the RAID info using an external dual-slot USB case and R-Studio, but seeing the info on this excellent site I figured I’ d try using my other identical, working 1TB LaCie drive instead, swapping the drives from the dead unit.

    So I swapped the drives, plugged in the power cable and the FW cable, but it still didi the same thing – no light, partly spun up, no mount (and no units visible in any drive utility). I thought this was a bit weird, since I knew this to be a working cabinet/case. To double check, I swapped the drives back, and tried to mount the original, working configuration – and now it gets really weird, as the same thing happened again – only now with drives and a cabinet/case that was working just a few minutes ago. No light, partly spun up, no mounting, no info.

    Any ideas? Did the finicky/brittle power supply on the previously working drive give out just because I disassembled it? Should I give up, or try the power-the-drives-from-a-PC trick?

    Any help would be greatly appreciated. I used to have these two drives manually mirrored, but then one of them gave out when I hadn’t mirrored the drives for a 8 months – taking a lot of music, photos etc with it. It would be so great if I could get my data back…

  • Hi Heimdall,

    That is very odd that both enclosures/drives are now doing the same as the first. The only thing I can think of, is the initial bad hard disk or power supply may have some kind of short which destroyed the enclosure. I would double check your enclosure connection. I would also try directly connecting a computer power supply plug to both drives and hearing how they spin up.

    It might be smart to just go straight from your desktop power to both harddrives and leaving the Lacie plugs out of the question aside from the IDE.

  • Mike, many thanks for the feedback!

    I too was really surprised when the second enclosure started acting the same as the first. I double-checked everything I could thing, and tried switching to another power brick as well (I have around ten different La Cie power bricks, all with identical specs, but none usually works with anything but the drive it came with – needless to say, I’m not buying any more LaCie drives…). I’ll give it another go this weekend and see if can get any results, but I also suspect that there’s a short somewhere. It seems the only logical explanation for the second enclosure to fail as well – unless the power supplies are so brittle that the power level required by one of the drives I was switching out killed the power supply of the second enclosure in the same way it did the original.

    I’ll try a desktop power supply as soon as I can get my hands on one, I don’t have a desktop computer at the moment but I’ll report back as soon as I’ve tried one. Again, many thanks!

  • Hi,

    I have a LaCie Big Disk that won’t power up. I am wonder what peoples thoughts are on this. I just received a new power supply from LaCie and this did not help. My problem is that the Blue LED won’t even come on. So, it appears my unit is not getting any power, as I assume the LED power would be independent of the hard drives, meaning that is was the hard drives that were faulty I would see the blue light come on. So that the fact I don’t seen anything means that the cause is fundamental to power coming into the unit.

    I like the idea of swapping drives into a new unit but looking for other suggestion to get this unit back up.

  • Hi Alex,

    First thing, do you hear the hard drive spinning up at all when plugged in?

    Second – I’d troubleshoot is the adapter to make sure its providing power. If you have a multimeter this is the way to go. This can also be done by seeing if an LED will light up when connecting it to the adapter 12v and gnd ports (what ports they were, were labelled on the back of my adapter).

    If I had to go further it would involve opening up the unit, and directly attaching the hard drive to a desktop power supply to see if it spins up.

    Those two tests would rule out lots. Essentially the big three pieces go from (1) AC adapter> (2) Inner Electrical Board [pcb] > (3) Hard drive. Doing the above would narrow the issue down to one of the three.

  • Hi,

    I have this harddrive and it was making a lot of clicking noises a while ago, but now the blue light turns on and no noises come from anywhere. It’s totally silent the entire time except for a tiny little squeaking sound right as it turns on.

    Should I go through with your tutorial above? I need to get this data off in the next day or two if possible but cannot afford data recovery.

  • I take that back, it is now emitting a very quiet, high pitched noise. Almost like a 56k connecting, but I’m still not recognizing it on my Mac and the drives are definitely not spinning.

  • Doesn’t sound good, clicking noises generally are of a failing hard-drive head. It COULD be that your power source was going in and out.

  • Well if that’s the case, and you have no other options at this time, I would say to try this out!

  • Mike this sure is kind of you to give this info! I had one fail and it is at my repair place. He says that the drives seem fine, but the i/o board is bad (the drive is model #301199U). I think I’ve found another luckily on Craig’s List, wow these are rare as hen’s teeth! And then we’ll try putting the drives in the other box.

    However, I talked to Lacie, and though I had a hard time understanding the tech person on the phone in every respect, I believe he said that the i/o boards are “married” to the particular drives, and that it may destroy the data to try another box and i/o board. This is of course frightening! My repair place, a very good place I think though their main thing is Macs, said that trying it shouldn’t hurt the drives.

    Can you share any thoughts on that? I am a musician and very un-tech savvy I am afraid. I have never posted online like this, it really is amazing and wonderful how someone such as yourself is willing to help a total stranger. Thanks so much for what you already posted above!


  • Hi David,

    You are very welcome. The board may very well be bound your particular set of drives however I find it a bit hard to believe why. I hunch in me still believes if you find a board of the EXACT same model it would still have a good chance. I also find it hard to see why that would destroy data on your drives, but in reality it is true that you have to expect the unexpected when working with recovery.

    I still think its worth a shot, just make sure the boards are 100% the same. Also do this as a last resort if this is the case. I can’t go in detail about this, but if you are very worried, I would talk to a technician and have your drives ‘ghosted’ (Symantec makes a product named Ghost) which can be made to perform an EXACT backup of the data on each one, whether or not the data is in a readable form.

    If anything happens they could be restored to the original state so something else could be attempted. However I must say this will cost money, the complete bit by bit copy will take very long (likely over 6hours each), and the same to restore if something bad did happen.

    I don’t know how far the tech looked, but if this unit is firing up (you hear it turn on) and the light on the front looks normal it may not be any hardware, but rather corrupted data. Curious, does any usb connection chime occur on the desktop after plugging in the external drive?

  • mike i knew it was possible but i was trying to figure it out thank you much i am buying a 500 watts power supply and firing up 6 lacie hdd i had sitting for over a year

  • if not found power led, and power supply its ok, another solution is in the small board, remove or cut diode, this diode is only for protection, but fail and produce one shortcut

  • Just found this page after looking for hours on the pinout on the power adapter, but for the most part I got it right I just wanted to make sure it was correct because I obtained this almost same exact model except mine is a triple interface 500GB. On the power pcb does anyone know what the 6 pin and the double 5 pin connectors are for? Im curious because there is nothing connecting from the power pcb to the usb/firewire pcb which also connects to the IDE to the 2 hard drives. How is this even possible? How can it power the IC’s if it gets its power from usb which would be the minimum. I can understand if it was just firewire, but it’s not.

  • Another question. Is the pinout on the ac adapter of the plug or the pinout coming from the external device?