Sony MSW-900 Operation Manual page 169

To release the time code synchronization
First disconnect the external time code, then set the F-RUN/SET/R-RUN
switch to R-RUN.
To change the power supply from the battery pack to an
external power supply during time code synchronization
To maintain a continuous power supply, connect the external power
supply to the DC IN connector before removing the battery pack. You
may lose time code synchronization if you remove the battery pack first.
4
Camera synchronization during time code synchronization
During time code synchronization, the camera is genlocked to the
reference video signal input from the GENLOCK IN connector.
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Chapter 4 Adjustments and Settings for Recording