IDE Hard Drive Replacement

Replacing an Old IDE Hard Drive Step-by-Step

I was visiting my cousin Henry some years ago when the hard drive in his wife's old Pentium MMX failed. It wasn't just getting noisy, a surface scan with ScanDisk showed that it was littered with bad sectors, most of which were right at the start of the disk where Windows wants to sit. In any case, it needed replacing, so the first job for Henry was to back up all the data that could still be accessed on floppy, then to remove the old hard drive. The case was a full cover type, four screws secured it from the back (of which two were missing), after which it slides off backwards. The old hard drive is exposed. Hard drive installed in mini-tower cage
Hard Drive in Cage

Unscrewing 3.5" IDE hard drive
Removing Hard Drive Mounting Screws
Hard drives in PCs are either mounted in fixed cages (as above), in removable drive cages, or on rails. The standard method in older clones was fixed cages, these being the cheapest to build and the hardest to work with. The problem is that while the two screws on the front side are exposed and easily removed, as shown to the left, the two screws on the back side or hidden within the case infrastructure and in some instances, even blocked by the motherboard! The view in this case was so obscured there was no point trying to photograph it, but keep in mind that you have to remove four screws to replace your hard drive.

Once the screws are all removed, the hard drive is sitting in the bottom of the cage. This won't always be the situation, some really cheap cages are open at the bottom, so the instant the last screw is removed the drive drops if you aren't holding on. Oddly enough, this is the most critical stage of replacing a hard drive, in the sense that removing the drive through the case where the ribbon cables are bunched up and over the CPU and heatsink is most likely to create another problem. If the cables are long enough, you can leave them attached to the hard drive as you slide it out, but don't try pulling through a mess, clear a path first. Removing the IDE hard drive from the cage
Removing Hard Drive

Dissconnecting the ribbon cable
Remove IDE Cable
Once the hard drive is out, you can remove the broad ribbon cable which carries the data and the 4x1 power cable. The ribbon cable is sometimes secured in place with a glob of glue or silicon to prevent it from working out of the drive due to vibrations. The 40 wire IDE ribbon cable is often keyed properly to the drive, but if not, the important thing is to get the red wire on the Pin 1 location. A new 80 wire EIDE ribbon cable is interchangeable (it has the same 40 pin connector) but the grounds won't be used. The power connector is often tough to remove just because it's a tight fit. Work it back and forth gently along the long axis, making sure you aren't flexing the circuit board as you do so. The jumpers for Master/Slave are between the two cables.

Excuse the glare from the flash, but I wanted to point out the label on the replacement drive. When you replace or upgrade any hard drive, you want to make sure that the jumper settings for Master/Slave selection on older drives are set correctly. The correct setting, in case of a replacing a drive, means they should be set the same way they were on the old drive. In this case, the CD drive is installed on its own cable and controller, so the proper setting was "Single" (same as Master on most drives) and didn't need changing. These setting are normally shown on the label on the face of the drive, as to the right. You can pick up an inexpensive 320 GB Western Digital or Seagate EIDE hard drive for just over $70. The 80 wire ribbon cable won't get you EIDE speeds on an old controller, but it will work. Installing the ribbon cable on the new IDE hard drive
Install IDE Cable

replacing the hard drive in the case
Replace Hard Drive in Cage
Since Henry was able to install the IDE ribbon cable and the power on the replacement hard drive while it was outside the case, all that remains is to slide it back into place and secure it. Again, since hard drive are three dimensional objects and fairly large relative to the size of the computer case, you have to clear plenty of room behind the cage to slide the drive straight in. Any time that you replace a hard drive and have new problems, like a CD that doesn't work or a new noise in the case, the culprit is usually a ribbon cable that's gotten loose on the controller while you were installing the hard drive, or a cable that's now hitting a fan.Install four screws (three is actually plenty) and the physical part of the job is over.

The 120 page printable eBook with 17 flowcharts and text for PC hardware troubleshooting can be instantly downloaded anywhere in the world for $9.95. Securing the hard drive after replacement
Install Hard Drive Mounting Screws

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