|Input impedance||1 MΩ // 47 pF|
|Deflection factor||10 mV/div to 25 V/div|
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.