If your 1t-vs-668 is a version 1 design you will see this issue and can't be resolved via a firmware update.
A possible workaround would be to use the analogue output but if your using HDCP content this will have limitations on the resolution you can output.
To resolve this issue you will require a version 2 unit which has a hardware modification to allow the Epson project to sync correctly with the HDMI output of the 1t-vs-668, Please see attach photo help identify which version you have 
If you've already got version 2 - please go into the OSD and turn on *timing shift function* (this is located under display in the menu)
*additional information*
the Epson projectors have a very low tolerance for H & V sync wobble and the chipset outputs a sync that wanders outside of that range (despite still being inside the legal range for the signal type). Basically the Epson projectors are being stricter than called for by the spec, and that's resulting in this compatibility issue |