On my Zune 30 with the 2.5 firmware, it appears that TV out may be broken. I have an Altec Lansing speaker/dock and it's connected to an old TV in my workout room. I switched the Zune to TV out and the TV screen blinked and the Zune screen went dark. No picture on the TV. I rebooted the Zune, no change. I've got another Zune 30 here, so I'll check that out either tomorrow or Thursday.
-steve