1. Digital audio cuts in and out. 2. Can I replace this 100 watt per channel receiver with one that is 110 watts per channel, and not risk damage to my 100 watt speakers?

I purchased my Sony STR-SE501 receiver in 2001, as part of a pre-packaged Sony home theater system with 5 speakers and a subwoofer. Recently, after the receiver has been running for 30 to 60 minutes, the digital audio sound starts cutting off and on. This occurs with both the TV/Sat and DVD/LD digital inputs. I have double checked all of the connections and the problem occurs with audio from both my cable box and DVD player. The analogue audio from the left and right audio inputs and the AM/FM tuner work fine. I have cleared out additional space around the top and side of the receiver to prevent overheating, but this does not seem to make any difference. Does anyone have any suggestions? If the receiver is going to require a trip to the repair shop, I am considering just replacing it, since it seems that a comparable new receiver would only cost slightly more than the likely cost of repair. I have been looking at a Sony STR-DG500 (6.1) receiver. My only concern is that the STR-DG500 is 110 watts per channel and the Operating Instructions for my present system state that four of my speakers (SS-V230) take a maximum input power of 100 watts each. (The center speaker will take 120 watts.) Am I going to damage my present (100 watt) speakers by hooking them up to a receiver with a power output of 110 watts per channel?

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