Cisco Application :: Active CSS 11501 Telnet And Console Not Working?

implementation of the cisco CSS 11501 boxes available as spare on our site into production for an application evry thing worked as expected. i was able to telnet the active/master box and was able to console both master and backup box from the console port.however a week post the activity im faced with this weird problem where im not able to take console or the telnet access of my primary/active box.The boxes are working in BOX-to-BOX redundancy and now im not able to telnet or console my active/master box. The telnet and console window prompts me for username and password and after entering the credentials nothing happens. no prompt or no error message is displayed.

The telnet primary authentication is via tacacs and secondary is via local. however for console im not using any method for primay authentication and local for secondary authentication. however i can successfully console my backup box. below are my obsrvations 1. the left and right status LED on the active CSS box is OFF.- it means my CSS 11501 failed and has no power. 2. upon firing the rcmd command with show line command on backup box i see that the telnet sessions and console session is established with the master box3. the redundancy state of the active box says it is master and has not changed state since my last activity, no application issue reported, all the services are active on the active box and also i can ping the active box ip address from my backup box over which box to box redundancy is established. This confirms the active box is functioning well 4. i initially thought the telnet sessions are not getting cleared, however the show line cmd with the rcmd cmd on the backup box confirms this is not happening. now im stuck as the active box cannot be accessed at all via console or telnet. i was thinking of below steps to be carried out.1. to failover the boxes and make the backup as master2. then try to take the faulty box off the network and troubleshoot (are there any other commands that i should use to troubleshoot)3. if nothing works try rebooting the box and check
 
NOTE: the software running is version 7.20.30.3 with standard feature set. we are not using cvdm or the CSS GUI. we could access the css initially on CSS gui and that is also not working now.