Interestingly, the 524 appears on page 33 of the 1966 RCA Test Equipment Catalog.
The 524 weighs 61 pounds, uses 500 watts, and has a thermal cutoff. It uses selenium rectifiers in the low-voltage power supply. It has a total of 4 kV CRT beam acceleration, -1.5 kV on the cathode and +2.5 kV on the anode. It normally came with a 5ABP1 CRT which has P1 phosphor, but P7 and P11 phosphors were also available.
The video trigger circuitry present in the 524 distinguish it from the 514. Just before the L-C delay line in the vertical signal path, there is a cathode follower, V15A, that serves as the trigger pickoff buffer. The resulting trigger signal goes to a video sync separator circuit. Here, the there is clamping and amplification and, most importantly, a non-retriggerable multivibrator. The multivibrator is triggered by the vertical sync of the NTSC waveform. After being triggered, it is not triggerable again for about about 25 ms, so it misses the vertical sync of the next interlaced field and instead triggers on the vertical sync of one following that. So it consistently shows the "even" field or the "odd" field. There is a switch that perturbs the multivibrator so it can be switched between even and odd fields. The video trigger circuit drives a conventional trigger circuit and sweep circuit similar to that of the 514.