So I had a dream last night about this issue (the addition of my projector to the mix and this thing's complete and utter failure weigh heavy on me) and at some point in the night I thought to myself "The HDMI repeaters are the problem.... 400+ people on Monoprice can't be wrong!"
So I found myself awake this morning, way earlier than I normally care to be. Before I went upending my working setup, I did some digging online and it turns out these matrix switches have signal amplification built in... maybe sleepy me is on to something but at any rate, that was enough to warn the family that there'd be no TV anywhere in the house this morning because dad's tinkering so find something else to do.
I removed the repeater from the 55" Samsung 7K series LED (2010 model) that I discussed earlier in this thread that was giving me problems. Instead of having it at the switch end of the cable, I brought upstairs to the TV end... no dice. Then I swapped the input and output on the repeater... less than no dice, didn't even gets signal. Grrrrrrr.......
With all hope exhausted, I decided to pull it from the chain altogether and lo and behold this switch is finally sending a signal to my TV! The next step was to load up a 3D bluray and go for the gusto.... no dice.... "This display is not 3D compatible" blahblahblah.
Then I remembered that I had the non-3D TV (the aforementioned older Samsung plasma) in the bedroom on from my previous testing. I turned it off and powered down the matrix switch and the bluray player and then rebooted without the non-3D TV and.... yep, fully working 3D.
So if anyone reads this (my posts in threads tend to be the last ones for some reason), remove any repeaters from the chain and you might have some luck. My 7K series Samsung wouldnt even try to show a picture but now Ive got this switch showing my HTPC and my Sammy Bluray with ZERO issues no matter how many times I bounce between each. The 3D does, however, die whenever a non-3D display is introduced.