No 1080p/50 or 1080p/60 through AV receiver

Question

Hi.  I have a new (2011) mac mini plugged into a new (2010) Yamaya AV receiver and Sony TV.  Both the receiver and TV are capable of running with 1080p 24/50/60 and this has previously worked with another HTPC I have.
When I plugged in the mini for the first time I got no video whatsoever.  From various testing including remoting into the mini to see what is happening whilst the screen is blank I've discovered the following:
Mini connected directly to the TV - All 1080p settings work fine
Mini connected through the amp - Only 1080p24 will work.  All 1080i settings 24/50/60 will work. 
Any idea why I can't get this working at 1080p/60 or 1080p/50?  My setup does support it, and my old HTPC would work on these settings fine.  I've tried multiple combinations of start up sequences and this has no affect.
Thanks,
Mat

Answer 1

You can try doing a PRAM reset which would force a
reseting of video parameters.  Do the following,
turn on the TV and wait few seconds for it to initialize.
Then power up the receiver and again wait a few seconds.
Then zap the PRAM as follows:
Resetting PRAM and NVRAM
Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.
Try this.