The main difference is that the 317 has more CRT accelerating voltage (9 kV versus 1.8 kV) for a brighter, sharp display. The 316 has a portable benchtop shape. The scope was also made in two other forms, the RM16 and the RS16. The RM16 is a rackmount version of the 316. The RS16 is also a rackmount version of the 316, but has the power supply in a separate unit so it can fit in shallow racks.
Early 316 units had selenium rectifiers. A modification kit, #040-216, was made available to replace them with silicon diodes.
The regular Type 316 scope runs on 50 Hz to 60 Hz power and has and AC fan motor. The 316-S1 runs on 50 Hz to 800 Hz power and has a DC fan motor. A kit was available to convert a 316 to a 316-S1 in the field. From the 1958 catalog:
- Fan Motor Kit — For converting Type 316 for use on 50 to 800 cycle line frequency (Type 316-S1). Contains brackets, rectifier, and fan motor. 040-141 Fan Motor Kit $40.00