[USR-TC] Chassis Power Problem?

Previously I had posted a problem with our Verizon PRI dropping randomly (sometimes up for days, somtimes only for hours). I tried different dual PRI cards and still saw problems but Verizon claimed the line tested fine. Monday, I ran to WRCA and picked up and HiperDSP and HiperARC and replaced the Dual PRI and Netserver. Everything seemed to run great until the line dropped again today. I'm starting to wonder if a shortage of power could cause the card to drop the circuit. Anyone think think this is possible? What are the power requirements for the 70A Power Supply. Is it possible that the circuit can't quite supply the needed power? Dan