Signal issues when connecting Canon 5D Mark II to external monitor through Blackmagic converter

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2016General Discussion forum

The Canon 5D Mark II disables its internal display when an external monitor is connected via HDMI.
A powered video distribution amplifier can improve signal stability when converting camera output to multiple destinations, preventing signal degradation and voltage-related damage to downstream equipment.
Using individual buffered outputs from a distribution amplifier is preferable to daisy-chaining video signals through multiple devices in sequence.
T-splitters should not be used with HD-SDI signals as they do not preserve signal quality, unlike composite video where splitting is viable.

The original poster's specific signal split-screen issue was not resolved in the thread.
No confirmation that the distribution amplifier approach fixed the Canon 5D Mark II signal problem for the original poster.
Discussion assumes HD-SDI workflow; compatibility with other video standards not addressed.