CRT 154-449 ---- T5032-31-1 (561A - not the same as the 561B)
The Tektronix Type RM561A Oscilloscope is essentially an indicator unit with provision for two plug-in units. The plug-in unit in the right-hand opening controls the horizontal (X-axis) deflection, and the plug-in unit in the left-hand opening controls the vertical (Y-axis) deflection. The plug-in units can be selected from any of the Tektronix '2' Series or '3' Series groups to provide the desired oscilloscope performance.
Type - T5032-31-1 (rectangular ceramic-envelope).
Phosphor - P31
Unblanking - Deflection type, dc-coupled, with grid intensification.
Graticule - Variable edge lighted "no parallax" internal graticule. Marked in 8 vertical and 10 horizontal divisions with each major division divided into 5 minor divisions on centerlines.
Accelerating voltage - 3.5 kv.
Useable viewing ares - 8 divisions vertical by 10 divisions horizontal.
Deflection meters - 18.5 to 20.5 volts per centimeter vertical, and 17.5 to 19.3 volts per centimeter horizontal.
Electronically regulated for stable operation with normal line voltage variations and widely varying loads. The low voltage supplies hold regulation within ±1% of value.
Line voltage requirements - 105 to 125 volts, or 210 to 250 volts, rms, 50 to 60 Hz, single-phase ac.
Fuse requirements - 3-amp slow-blowing type for 117 volts, 1.25-amp slow-blowing type for 234 volts.
Forced air cooled. Automatic-resetting thermal cutout interrupts instrument power if internal temperature exceeds about 123° F.
Weight - 30-1/2 pounds, indicator unit only. (no plug-ins)
excerpts from R561 Manual