Replacing a Hard Drive

Illustrated How to Replace a Hard Drive

I've decided to replace the step-by-step illustrated guide for replacing an IDE hard drive on this page with a more general guide to replacing SATA hard drives. So let's start off with the standard SATA power connector. New ATX power supplies are all built with a number of these SATA connectors, but if you're replacing an SATA hard drive in an older system, if you follow the power connector back to the power supply you'll find that it's actually an adapter, fit to an old fashioned connector. That's fine, the power is the same, it's just the shape that's different. The new SATA power connectors, as shown below, are much easier to insert and remove than the old fashioned ones.

The SATA data connector is right next to the power connector and uses a smaller format. This is where the "S" in "SATA" comes in, it's "S" for "Serial". The old ATA drives used parallel connections, with a 40 wire data cable, or 80 wires for the higher speed cables that used extra grounds. Note that you can always replace the old 40 wire IDE cable with a newer 80 wire PATA cable. So the SATA data cable requires far less real estate on the hard drive, is much less prone to failure, and completely removes the old hazard of bent pins and cables without key being forced onto the hard drive backwards.

You'll sometimes need to replace an SATA hard drive in an older system that used the hybrid Western Digital Secure Connect system, which is now obsolete. Many early SATA hard drives came with both an SATA power connector and an old fashioned Molex power connector, to support old power supplies. So the Secure Connect cable snapped over both the SATA connectors for increased support, even though the power part of the connector was just an empty dummy which allowed them to include guides for the connector on both ends. It really wasn't necessary, but it was clever branding to differentiate from Seagate, Maxtor, Hitachi and IBM.

Older SATA drives, including those using Secure Connect, had to be connected to the power supply with the old-fashioned Molex connector, as shown below. These connectors were always a weak spot on hard drives. I remember replacing a hard drive where somebody had broken the connector right off the circuit board while trying to seat the power lead. They really were that tight.

The picture below shows the SATA hard drive data connection to the motherboard. These are extremely straight forward and keyed so they only go on the right way. In this case, the old parallel IDE cable to the left connects the DVD recorder data.

All quality ATX cases include a removable drive bay. These make it much easier to replace hard drives by saving you from having to remove both sides of the case to remove the screws on both sides of the drives. Removable drive cages also eliminate the possibility that the motherboard will block access to one or more screws with a big motherboard in a small case. The standard method is for the case to lock in place with a single lever, though some use a screw and others count on gravity.

The high quality hard drive cage in this case included rubber shock mounting screws, which can't hurt, but aren't really required. Shock mounting hard drives is a necessity in laptops, but it's probably overkill in desktops. I always use four screws, two on each side, to secure hard drives. Given thermal expansion and contraction in computers, it makes sense to do things as evenly as possible, even though four screws clearly aren't needed to keep the hard drive from running away. The even support may reduce the stress on the hard drive casing, though most of these are pretty solid to start.

This hard drive cage slides back into the case from the interior, which can be a nuisance if you have any long adapter cards installed on the motherboard which have to be removed and replaced to make way for the cage. I prefer the design that let's you remove and replace the hard drive cage from the side. This is especially true as there's no longer any need to push the drive cage forward to get access to the front of the case for a floppy drive or other 3.5" media, all of which are pretty much gone.

The final step after installing or replacing hard drives is to clean up the cabling, especially given all the active heatsinks with fans in modern PC's. It only takes a second to snug up a wire-tie on the SATA data cables to keep them from flopping all over the place, and even if you replace the hard drives later, the cables should still reach the SATA data connectors.

Hard drives are one of the few components in the PC that it can make sense to replace before they go bad. The price of hard drives falls so rapidly that you can often increase the storage capacity of your computer by a factor of 5X or 10X for less than $100. But when the hard drive does fail, the results are often catastrophic. Computer Repair with Diagnostic Flowcharts will help you troubleshoot hard drive problems, from boot failure to poor performance. The 120 page printable eBook version with 17 flowcharts and text can be instantly downloaded anywhere in the world for $9.95. Even at today's ridiculously low hard drive prices, the eBook is a fraction of the cost, and you don't pay for shipping:-)

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