This MIGHT be a power supply problem. When you have the case open take a look at the capacitors in the power supply , looking for any that have bulging tops.
Background: I have several DirecTV HD DVRs. Last summer I noticed the oldest one was stuttering on playback. Several years earlier I'd upgraded it to a 1 Terabyte drive. My first idea was that the replacement drive was getting flakey; since it was full I replaced it with a 2 Terabyte drive. When I ran advanced diagnostics on the 1 Tbyte drive it passed with flying colors, so I put it in service in a non-critical computer. A few months later the 2 Terabyte replacement drive began exhibiting the same problem, eventually refusing to even complete the startup process. When I pulled the drive it failed diagnostics. As I was reinstalling the original drive I realized that several low voltage caps in the power supply area (the design has the power supply on the main board) were bulging on top. Rather than risk the original drive, I left the DVR out of service until I could replace the caps; it's been working perfectly with a new 2 Terabyte drive for the last six months. When I tested the bulging caps they were definitely bad - the capacitance was much lower than specs and the ESR was much higher. These caps filtered the power for the drive (as well as other areas), 'noisey' power to the drive caused read errors.
After returning the first 2 Terabyte drive for replacement I learned some bitter news. When a drive has problems reading a sector it marks it as bad and maps in another sector as a replacement. When the bad sector map is full it will report itself as bad. There are utilities that will purge the bad sector map and allow normal operation. If I had done that I could have recovered all my original recordings.
There's a difference between needing help, and just being plain ole' lazy.
"You cannot teach a man anything. You can only help him find it for himself." Galileo Galilei (1564-1642)
HR20-700 with 2 TB, HR22-100, HR22-100, HR22-100, HR23-100 all running 0x5cd and networked.