500-series plug-ins (Letter-series and 1-series)
These plug-ins fit in 500-series scopes and in external power supply units such as the 127, 132, and 133. They use the 500-series plug-in interface. The transition from letter-series plug-ins to 1-series happened in fall of 1965.
Tektronix made plug-ins
A – 20 MHz single channel amplifier, 1959 (53A: 1954)
F – 1 MHz high gain differential amplifier (Prototype, became the 1A7 before going into production)
J – Similar to 1A1 (prototype only), 1963
N – 600 MHz sampler, 1960
O – 25 MHz op-amp, 1962
Q – Transducer driver, 1960
T – Single time base, 1957
V – video amplifier (prototype only)
1S1 – 1 GHz, sampler, 1965
1M1 – Calibration aid, 1964
Non-Tektronix plug-ins
... that also work in 500-series scopes include, but are probably not limited to:
Hickok 1822 – Tektronix Type B clone
Hickok 1823 – Tektronix Type 53C clone
Hickok 1823A – Tektronix Type CA clone
Hickok 1824 – Tektronix Type D clone
Hickok 1831 – Tektronix Type K clone
Hickok 1832 – Tektronix Type L clone
Lavoie LA-265-B – Tektronix Type B clone
Lavoie LA-265-CA – Tektronix Type CA clone
Lavoie LA-265-D – Tektronix Type D clone
Lavoie LA-265-L – Tektronix Type L clone
Lavoie LA-545-54L – Tektronix Type L clone
Pentrix L20 – Spectrum Analyzer, forerunner to Tek 1L20
Pentrix L30 – Spectrum Analyzer, forerunner to Tek 1L30