Just wanted to pass this on for what help it might bring.
Recently did a job with the Scarlet for the first time. Needless to say, and in their grand wisdon, Red decided to completely throw out the old Red One menu scheme and replace it with nearly a complete new one, including icon changes as well. Anyway... after realizing that the old "chain" icon for jam sync was replaced by the word "Jam" (yes, that term was reserved for another menu function on the One), we still (both myself and the AC we're stumped) couldn't get the Scarlet to take hardwired TC output from my 744T with the Scarlet as slave.
IN the end, we realized that ever time the Scarlet is powered down, or any number of other little tweaks are made with the camera, you must physically disconnect the TC connection in order for the Scarlet to grab incoming TC and lock to it, finally displaying the locked, matching TC on it's monitor.
Tom