I came home yesterday to find the package from Replaytv.us (aftermarket parts and repair shop, not affiliated with ReplayTV). In the box: one ReplayTV formatted hard drive (rated 125 hours, 5400rpm); one 'stealth' fan. I had decided to try out a fan inside the box to see if that would extend the life of the hard drive. The guy at Replaytv.us says he has the same model of box I do, and that he has the same model of hard drive I bought and has been using it, without ventilation, trouble free for several years. Apparently the 5400rpm drives run a good deal cooler than the 7200rpm drive I installed myself a few years ago. Still, I was experiencing some paranoia, what with programming freezing every minute or so, and I ordered a fan.
After dinner I took apart the Replay box and swapped out the hard drive. Installing the fan was easy, though it's clearly an aftermarket hack, since the model of ReplayTV I have, a Panasonic Showstopper, was never engineered with a fan in mind. The shop supplied an extender post that screws into the motherboard; the fan has a metal arm (melded into it's plastic frame) that screws into the extender. Then the fan has a splitter that vamps on the power supply leading to the hard drive.
First thing I discovered is that when the unit is plugged in, the power supply to the hard drive is always on. The motherboard sends signals to the drive over the data line to tell it when to spin up or power down. As a result, the fan is on all the time. A hack, as I said. More disturbing is that this Vantec 'stealth' fan made a huge amount of noise. I closed the door of the entertainment center for the first time that evening, and it was still annoyingly loud. "This could be a problem," I thought.
I resolved to let it run at least until the weekend, and open the box and fiddle with the post mount on Saturday if it didn't quiet down with operation. [I noticed it was much quieter, though still audible, this evening.]
Once I'd programmed in my standard shows, I set it to record something showing right then to test it out. After watching it replay for about fifteen minutes without any glitches or hangs, I decided it was passing the smoke test and went upstairs for the night.
This evening, Jean and I watched a show from beginning to end without hangs, and I watched one show by myself that had a single glitch. I'm not sure yet if this was due to the ReplayTV or embedded in the program stream. I deleted the program after watching it, so now that I think of replaying that stretch where the glitch occurred (a pause in the show that corrected itself), it's too late to check.
It's early days, but I'm provisionally convinced that the hard drive replacement was all that was needed. In a few days I may pull the fan out due to noise, and trust that the 5400rpm drive is cool enough to run for at least a few years. Cross those fingers!