I was installing a Blu-ray player in the theater of one of our parks, and ran into a problem with the HD-SDI signal. Output is 1080i, and projector native resolution is 1366x768. First I had it temporarily connected directly to the projector. The 1080i signal would jump around, while setting output to 480i or 480p would result in a stable signal. I then connected the Blu-ray player through a Gefen HD-SDI 4x1 switcher, and the problem went away. It made me think that the switcher might be re-clocking the signal or something. When it came time to do the final installation--switcher included--the problem was back, and would even occasionally drop to black. I swapped cabling (1694A) around, swapped inputs around, etc., and nothing helped. 480p was still stable. I didn't have any other HD-SDI sources/monitors available at the time. My guess is that #1- the Blu-ray's HD-SDI output (modded by JVB Digital) is not to SMPTE spec, and/or #2- the projector input is not very tolerant of wayward signals. I think a re-clocking switcher or DA may fix it. Cabling distance is about 40-50 feet total. Is my assumption correct? Here are some photos.
your projector may not support scaling of signals. This means that it is possible that your 720p native projector may not be able to handle a 1080i signal.
You need to go into your PROJECTOR menu settings, and search to see what it is expecting to see. Do not assume that it will just work. I just hooked up a cheapo DVD recorder for someone that "did not work". I had to change the setup menu from 480p to 480i to get it to work. Assume nothing. I am sure that your BluRay is fine. If you are using 1694A for only 50', this is not a cable issue.
This will ultimately get resolved (probably) by screwing around with the input select menus (for format) in the projector.
In addition to our state parks division, our state lands division has several parks of the "field trip" type. This one is the 5 rivers delta resource center at the top of mobile bay. The pj supports up to 1080i59.94 input video. I'd rather send 720p from the blu ray but the hdsdi output doesn't support it...only 480 1080i.