555

The 555 is a dual-beam CRT oscilloscope made by Tektronix from the late 1950's until the late 1960's. The system is split it two pieces: the main indicator unit and the external power supply unit. The power supply unit contains the transformer, rectifiers and regulators for all of the voltages except the filament and CRT HV supplies. The filament and CRT HV voltages are generated in the 555.

The 555 takes letter-series and 1-series vertical plug-ins.

The 555 uses special horizontal plug-ins that contain the trigger and sweep. Early instances of the 555 came with the 21 and 22 horizontal plug-ins. Later instances came with the 21A and 22A horizontal plug-ins, which use tunnel diodes for triggering.

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  front view: two timing plug-ins on top and two vertical plug-ins on bottom

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  external power supply

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  left side view

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  right side view

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  top view