I had an unusual problem arise the other day (New Year's day, actually, nice way to start the year). This could just be a 630 problem, but because it involved my external HDD (a WD 1Tb PVR Expander) I'll post it here. In the early hours of New Year's Day I left the 630 recording a program with a couple more to go.
When I got up, the 630 display was stuck on 7:00; i.e. it appeared that the time was frozen at 7 o'clock, and the unit would not turn on (the bottom dot of the time colon flashed a couple of times, that's all). A couple of front-panel resets did nothing. Same with power and input signal cables disconnect. I then disconnected the eHDD and did another front panel reboot and the 630 returned to normal, with a message that it couldn't find the eHDD. It did have all my recordings listed, but grayed out, and I couldn't access them. I did another front panel reboot to 'reconnect' the 630 with the eHDD but the 630 again showed 7:00 (oh oh!)... then turned to 7:01 (time was passing, once again), and then just as I was despairing that this was going to be a big problem, the correct time appeared, the connection was reestablished with the eHDD, all my recordings were available, the timers were intact, and so on.
The only problem I've found is that one of those programs set to record during the early a.m. hours of New Year's Day stopped before completion (about 20 minutes into a 30 minute program). BTW, that program should have been finished long before 7:00 a.m. so I don't think that the 7:00 display reading was in fact the time (error code?).
I have only been using the eHDD for about 3 weeks, but it installed without incident and has been working fine, and even now I can't say that this event was its fault.