I get the same issue when trying to use the net radio, tuner on the TV connected to hdmi 1 i get nothing on screen and yet i think i should see the receivers menu for controlling these functions.
Similarly when i try to select one of the sources on AV2 or 3 i get a blank screen on the TV too.
First guess is it's a resolution issue. The display isn't syncing with whatever resolution the other sources are sending. I presume they are lower quality than the sat receiver so bandwidth shouldn't be the cause.
As a possible other cause.... I use a Yamaha receiver (same deal with two different models) with dual HDMI outputs (tried both). One display is a LCD (PC) monitor that doesn't have HDMI. So I use DVI instead and it's a pain in the neck. Every time I change resolution the display goes blank (I even tried the service menu tweak MON.CHK) and I have to turn it off and back on to get the image back. Might be having similar syncing issues with your extender. Pioneer didn't have the issue and Marantz and Denon to some degree... if I remember correctly.
Edited by Charles R - 7/29/13 at 11:12am