Hi,
is there a trap for when a stack member goes down ??
We tried shut a unit down and got no trap, only in syslog you could see a unit leave and stacking port go down.
Yes. These KB articles were written before B5/C5 release, but the outlined "later firmware" behavior applies to them as well:
7224, "Stack Failure traps on the SecureStack products" (http://bit.ly/1pOkniZ) 10381, "SecureStack Generated a Trap referencing OID 1.3.6.1.4.1.52.4.2.31.1.0.1" (http://bit.ly/1fPYJkP)
I will add that you should be running firmware 6.42 (November 2010) or higher.