I was on QF 583 SYD-PER last Wednesday night on a 743. Departure was delayed 90 minutes with the reason on the board shown as 'delay due technical requirement'. On board the captain advised there was a problem with the aircraft's radar prior to it leaving Perth earlier in the day. Then yesterday (Sunday) I was on QF 566 PER-SYD. This is a scheduled 743 but there was a change of aircraft to an A333. I also notice that from about mid-year there are about two flights per day SYD/PER operated by A332s (or A333s, I can't quite remember).