Any one using Cyberpower UPS's which have failed to the 4 beeps which the manual only states to check with Cypberpower on possible repair via warranty. Any one determined what the condition is that causes the 4 beeps? Battery has gone bad? Internal Fuse? I have one of the Cyberpower 500SL that after working great for about 2 years, after returning home from one of the numerous power outages I found it was dead, and would not reset. It just makes 4 beeps and the battery outlets are dead, no voltage. Cyberpower was, well, less than informative about what caused this problem.I figure its either the battery needs replaced or there is an internal fuse that has blown that needs replaced. As from the indications from Cyberpower its repairable at a cost, so it doesn't seem to be a total loss. Any one diagnosed this situation and found an answer. I would like to repair this unit and put back into service if its a simple battery change or internal fuse repair. The lack of a substantial answer from Cypberpower just to make a buck on a repair annoys me.