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I was having problems with a new hard drive I purchased recently. I had an old 300GB Maxtor drive connected to my system using a standard SATA cable that came with my motherboard. It worked fine for a while, then I started to have problems with it. I ran various tests, and determined that the hard drive was dying. Then, one day it would not work at all. I had to put it in the fridge for about half an hour, then hot-plug it into my system to access. I am lucky that SATA is hot-pluggable. If I booted with the drive plugged in, the system would hang at the BIOS. Once I got it in, I was able to use SyncBack to copy all my data off. The drive seemed to fail when it got warm, so it took a few attempts. Luckily, SyncBack was smart enough to continue copying where it left off, instead of re-writing all the files. Let me tell you, SyncBackSE (the pay version) is well worth the $30 it costs. I highly recommend it. I was able to make a complete backup of my drive and send in the bad one for repair. Since Seagate bought out Maxtor, I didn’t receive my drive back, but a 320GB Seagate drive. That was kinda cool, a free 20GB of space, just for having my drive fail.

Anyway, while that was being repaired, I bought a 500GB Hitachi drive. It is actually the 3rd 500GB Hitachi drive in the system, and I have had good results with the previous two. When I installed the new drive, I plugged it in where the old drive was, using the same power and SATA connections. This worked for a while, then a week or two ago, I started having problems with the new drive. It would fail to be recognized by the system at boot up, or sometimes Windows would just hang when I tried to access the drive. I was pretty sure the drive wasn’t dead, but to make sure, I took it out of the system and connected it via my handy CoolGear USB to IDE + USB to SATA combo kit. It worked fine there, solidly, no matter how warm it got. I did a lot of benchmarks on it and just raw data copies, just to make sure. I finally decided the drive was fine, and put it back in my system. As soon as I plugged it in, it started failing again. I realized that the only thing left to check now was the cables connecting it. I picked up an extra SATA cable from work and connected it. I haven’t had any problems since then.

So anyway, now, to get to the point of this post. I took apart the culprit SATA cable. Disassembly was pretty easy. There were two rings around the back end of the connectors. I didn’t take a picture of them before I popped them off, but they held the shell for the connectors together. Once those rings were off, I was able to wedge the knife between the two halves of the shell, and pop it off, exposing the bare wire leads inside. Next, I sliced down the middle of the plastic shell and extracted the cable by pulling on it. I just scored the wire and pulled the wires, which cut through the soft plastic casing. Here is what I found inside:

Inside a SATA cable

It is kind of what I was expecting, but not entirely. There are three bare wires, which I assume are ground wires. They have no insulation, other than the outer casing of the SATA cable. They connect to pins 1, 4 and 7. I also found that there are insulated and shield wires connecting pins 2, 3, 5 and 6. Pins 2 and 3 are paired together, as are 5 and 6. I don’t really know much about the SATA spec, but I’m guessing one is TX and one is RX. There are two pairs, similar to a CAT5 cable used for Ethernet (since two pairs are not used in Ethernet). This is probably so that the communication with the SATA device can be full-duplex. That’s pretty cool. Although the pairs are shielded, they are not twisted. The wire is solid, which is to be expected, since it’s really tiny, but I don’t know the exact gauge.

So there you have it, now you can see what is inside a SATA cable.

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