Why aren the cameras sending frames with the OptiHub in external trigger mode?
When operating in External Sync mode the OptiHub blue LED indicates the external trigger status. If the blue led is not blinking, that means the OptiHub is not getting a valid external trigger signal so the cameras will be stalled. This is the intended behavior, so it is important to make sure your external trigger signal is functioning properly. If needed you can investigate further by putting a scope to the Ext Sync-Out jack when the problem occurs. If you are using a video adapter sync out as your source, you should be seeing a 50% square-wave at half the frequency of your video adapter’s screen refresh rate. When not in Shutter Goggles Synchronization mode, the OptiHub free-runs even when the Ext Sync-In signal is missing, which is why the blue led blinks then.
