RCA CC6364/CC6374 - Manual (Page 36)

Using the Monitors
34 Chapter 2
Appears when the time base corrector is turned on (see page 46).
Appears during playback. It is not recorded. An M appears in front of
the time counter when memory-stop is on (see page 47).
Indicates the approximate time remaining on the tape.
TBC (Time Base Corrector) Icon
TBC
Time Counter Icon
M0:00:00
Time-Remaining Icon
120MIN