I'm fairly new to this, but in doing configuring/testing of 5510s, I have an issue with just one unit. I'm bringing the SCL up to level 5 from either 0 or 2, then doing a config. for our customer, then running a test on all the connectivity. Once that is done, I then reload to factory defaults at which point this one unit fails to re-boot properly and I get the mssg.: Autoboot failed, rebooting. The unit then gets into a loop of cycling through this until I gave up and shut it down. Could it be a bad SSM Module, or is the mainboard messed up? Any thoughts might help me out come Monday when I go back to work... (General Dynamics C4 Systems). Thanks for any input.