1: Unknown
2: VSS
3: Composite
4: VCC
5: REC (+5 VDC)

Notes: The composite requires the signal ground to be connected to the VSS of the circuit, or it has issues syncing. Pin 1 seems to kill the CRT if grounded, and tends to be -8 VDC. I wonder if it's a regulated negative voltage source for some obscure circuit in the camera, but has gotten weak over the decades, and that's why it's completely dead in situation in the camera, but works on the bench.