HR22-100 Stutters on recorded programs

For the last few weeks, my HR22-100 receiver has been acting up. It works fine on live TV, but recorded programs have odd glitches, almost hiccups every 30 seconds to every few minutes. If I rewind to the spot that hiccuped, it doesn't occur at the same spot, but will reoccur.

I have run hard drive diagnostic tests (short and file) and they are fine. It makes watching recordings irritating. BTW, I have the same model receiver in another room and it works just fine. Any ideas before I go thru the CS gauntlet??