UPS? There is nothing in the programming of a 2950 that would cause a "squeal". Could be a hardware/electrical fault, but if it is a constant high-pitch squeal, it sounds like the UPS.
I've been using this sever for a couple of years without any issues until I moved from Atlanta to Florida.  The unit was packed and moved very carefully and there were no incidents during the trip like locking up the breaks, flying across the median, huge pot holes, etc. When I first powered the unit after the move it has a high pitch squeal that's non-stop.  This happens as soon as the power is turned on and before the drives spin-up.  The drives are what I first thought but not after watching the power up sequence.  They are 6 ea, 2T SATA's off a PERC 6i running RAID 5. I've checked the logs and see nothing to indicate any issues, searched the web and the Dell forums without a hint of what may be going on. Has anybody heard of anything remotely related?  Any thoughts, suggestions, etc. please.  
PE 2950 - High Pitch Squeal???