[USR-TC] hub status led red

I have a Total Control Access Server. I have a problem with it. Periodically it goes dead. And hub status led gets red. I cant make telnet connection to it. I just make a cold reboot and it continues working. The room is not hot. So the TC is not hot also. 2 AC is cooling the room. Where is the problem. Regards, Murat Kucuk www.ebim.net U.S. Robotics Total Control (tm) NETServer Card V.34 V3.3.3 Build date: Nov 27 1996 Build time: 17:06:59 Network Interface Card: Ethernet (24) Packet Bus Circuit : Standard Licensed for 60 ports.