Hi I am not sure of the recovery procedure for a 303, but I did read a previous post about this and they recomended trying the following.
Power off , wait about 30 seconds, Power on...
Within 15 seconds type : NetICs<cr>
You will then be in enable mode... You should be able to retrieve the password from the security menu.
This is a procedure for 450 T's but it's worth a try
best of luck
Bob ^^