Seagate Expansion 3TB External HDD – What’s Inside?

The majority of external hard drives are nothing more than a case, a USB-SATA adapter, and a standard 3.5″ or 2.5″ hard drive. Despite having this extra hardware, they sometimes actually cost less than their bare counterparts. Why might this be? External drives usually only carry a 1 year warranty, while the average desktop drive today might get 2 years of coverage.

tmp_15513-20150127_1737431938407003                  tmp_15513-20150127_1737581841296918

Above is a 3TB Seagate Expansion external hard drive. It has a USB 3.0 interface, and accepts 12VDC for power. I bought this a few years ago for $10 less than a bare 3TB SATA desktop drive.

Western Digital released a line of external hard drives where, when you take it apart, you don’t find a normal drive inside. Instead, the control board is actually a USB interface, not SATA.

Out of curiosity, and because I might put this drive inside my server in the future, I decided to tear it apart to see what I was working with.


There are no screws holding the case together. Just begin prying from the front lip, and work your way around with some gentle force.

There’s no way around it: you will break the clips. These hollow frame clips are practically designed to break.


At this point, you have 3 parts: the base, the lid, and the drive cradle. Moving on to the drive cradle, you will see 4 rubber pads:


Behind these are Philips-head screws, which hold the hard drive to the aluminum frame. Once you remove the screws, you can simply slide the drive horizontally, to disconnect it from the USB-SATA circuit board.

tmp_10379-20150127_172221596439026   tmp_10379-20150127_1722461841296918

It is a standard, ST3000DM001 3TB desktop hard drive. The serial number on this drive does not match the serial number on the enclosure.

I checked for warranty status with Seagate, but this drive is no longer under warranty. This is not surprising, it was manufactured August 2012. However, what would have been interesting to see is whether or not the drive itself had 2 years warranty, despite the entire assembly only having 1 year. I suspect it would be flagged as an external-bound drive, and not be eligible for replacement.


So there you have it – inside the Seagate Expansion you find a standard, ST#000DM001, 3.5″ SATA hard drive. You likely won’t be able to take it apart without breaking clips, but it will still close just fine.

This drive is available from 1 – 5TB, and sometimes is on sale for less than a bare drive. If you never adhere to warranties anyway, you might be able to save some money.

Tags: , , , , ,

Tuesday, January 27th, 2015 computers, electronics

Leave a Reply