I decided to increase the hard drive capacity on my DirecTV receiver (model HR20-100). It comes standard with a 320GB drive which was always at 90-95% utilization. I just happened to finish upgrading my system HD from 500GB to 1TB, so I used my old 500GB as the DVR drive. Below are the pictures taken to replace the drive. It was pretty easy — you just need to unscrew a bunch of screws, take the old drive out, put the new one in, then put all the screws back. The system will autoformat the drive and it will be ready to use. If you wish to save your old data, you can always use ghost/dd/whatever your favorite mirroring software is to save your settings.
PS. The DVR allows for an external drive to be connected via E-SATA, but I did not want to take up any additional space in my media cabinet.
