3A2

The Tektronix Type 3A2 is a dual-trace amplifier plug-in introduced in 1963 for 560-series scopes. It was designed for compatibility with the digital unit in the 567, e.g, the 6R1 or 6R1A.

Tektronix Type 3A2
Dual trace amplifier plugin Type 3A2 front view Compatible with 560-series scopes Produced from 1964 to 1974 Manuals Tektronix 3A2 Manual (PDF) Tektronix 3A2 Manual (DjVu) (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

Key Specifications

Bandwidth	500 kHz
Input impedance	1 MΩ // 47 pF
Deflection factor	10 mV/div to 25 V/div

Internals

The input signal passes through compensated attenuators and then into a 12AT7 cathode-follower stage. Channel switching in ALTERNATE mode is done using diodes. The output stage that drives the vertical deflection plates of the scope uses a pair of 6BA8 pentodes.

The "CHOP" mode of the 3A2 switches back and forth between the two inputs at a rate of a few kilohertz. The signal that causes the switching is generated by a relaxation oscillator formed using a capacitor and a pair of 152-108 Shockley diodes, D385 and D386.

Pictures

Channel 1 Input Amp
Channel 2 Input Amp
Switching and Output Amp
Attenuator Switches