The Sup2 only needs the normal fan tray to operate so i suspect what you are seeing is that when you put the FAN2 in it is simply that the supervisor is drawing the amount of cooling it would from a normal fan tray ie. it doesn't need anymore so it doesn't draw it. Actually it may not be able to draw it as most things on the 6500 are hardware limited.
What i wanted to do was install a X6748-GE-TX in the switch.-
I was under the impression that the card whould just connect to the SUP2 bus.. And not use CEF720
And the only thing i get when i plug in is that "in suff cooling" and the card has been powered off.
You cannot use a WS-X6748-GE-TX module without a supervisor 720 in your chassis. All 67xx modules have to have a supervisor 720.
Edit - just to explain a bit more. The WS-X65xx modules are fabric enabled. Fabric enabled means they can use either the classic shared bus or if there is a switch fabric they can connect to that. To provide a switch fabric with a sup2 you need an SFM (Switch Fabric Module) in the chassis.
However the WS-X67xx are fabric only linecards ie. they cannot connect to the 32Gbps shared bus. They have to have a connection to the switch fabric and because of the connections they have to the switch fabric they need a sup720.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...