I've had my 990 coming up on 3 years now. I did the first upgrade when it came out, no problems, and did the latest upgrade in June, again no problems. About a week ago I started noticing distortion in the 5.1 Dolby format. I started my process of elimination -- the distortion came from more than one DVD and it came from both my primary and a backup DVD player. That eliminates media, player, and connects as problems. I then played some distorting material using the Dolby Digital headphone settings (5.1 source with DH1/2/3) and the distortion was there. This eliminated speakers and external amplification (the 770) as a problem and nailed it to the pre-pro. Also the distortion was limited ONLY to Dolby 5.1 -- DTS 5.1 was fine as were all other formats. So I was preparing to call Outlaw to report the problem and expecting to have to ship it in for service. But before I did that I thought that I would try a full reset and reload of the latest firmware. I did so not expecting it to do any good but lo and behold after the reset the problem was totally gone! With it working again I did not wish to risk a reload of firmware (3.24 is still verified in the window) so I resolved my problem with a factory default reset. This is great, but I am left with some wonderings and questions that I would like to ask of anyone who can help:

1. What could cause only 5.1 Dolby processing to go bad? -- Anything I can to to prevent it from happening again?
2. Why would a simple reset "fix" the issue? Can I expect this to happen again a week, a month, a year later?
3. Anybody else have this issue? Results?
4. Should I send it in anyway if it happens again even if the reset clears?

Anybody who can provide any insight to this would be most appreciated ---- Thanks.