Any Krell KAV280p owners out there?

My Krell KAV280p preamp has developed an intermittent problem that (hopefully) someone will recognize. During normal operation the preamp suddenly switches into standby mode. Turning the unit back on may bring it back. Yesterday it did not. This morning it appeared fine. The unit sits on the floor with nothing above it, so heat can't be an issue. Does anyone: A) Have any suggestions? B) Know of any reputable service shops in the Philadelphia area?
This is a known defect by Krell. If you call them, they should fix this for you. Give them a call and see what they said. When I owned this unit they did it for free. Cant hurt to ask... They will also test the unit and make sure its running at full spec. There customer service is great but expect to wait at least 4 weeks to get it back no matter what they say...