422: Difference between revisions

Revision as of 13:42, 7 June 2020

{{{manufacturer}}}

15 MHz portable dual-trace scope

Produced from 1965 to 1975

Manuals

(All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix Type 422 is a 15 MHz portable dual-trace oscilloscope introduced in 1966. It was available with an optional battery back for operation without mains power.

Specifications

please add

The post-deflection acceleration voltage is 4900 V.

Internals

Early versions use an 8056 Nuvistor tube for the front-end cathode follower. Later versions use a FET front end. The 8056 Nuvistor used in the input amplifier of the 422 can be replaced by a MPF102 JFET.

The trigger circuit in the 422 has a trigger amplifier driving a 1N3719 tunnel diode, D375, which acts as a Schmitt trigger. The trigger amplifier has a nonlinear deadband diode circuit in the negative feedback path. What results is high gain for small signals (little or no negative feedback) and low gain for large signals (strong negative feedback). Thus, the signal at the base of Q364 has a limited swing over a wide range of input amplitudes. The collector current of Q364 varies between 0 and 9 mA. Depending on the position of the trigger slope control, higher collector current in Q364 either switches D375 from the low-voltage state to the high-voltage state or from the high-voltage state to the low-voltage state. When D375 transitions from the low-voltage state to the high-voltage state, it produces a current pulse in the primary of transformer T401, which produces a current pulse in the secondary of T401. The secondary of T401 feeds another tunnel diode, D405, and the current pulse switches D405 to the high-voltage state, which starts a sweep.

The 422 uses the T4220 CRT.

Links

Pictures

External

R422, compartment closed
R422, compartment open
Black 422, panel mount
422 trace is sharp
422 in ALT

Internal

MPF102 replacing 8056

Schematic

Trigger circuit
Sweep circuit
Vertical amplifier circuit
Input amplifier circuit
Horizontal amplifier circuit
CRT circuit
ac-dc power supply
ac power supply

@@ Line 52: / Line 52: @@
 ==Pictures==
+=== External===
 <gallery>
 Tek 422 front.jpg
 Tek 422 side.jpg
-Tek 422 trigger.png|Trigger circuit
+Tek r422 1.jpg|R422, compartment closed
-Tek 422 sweep.png|Sweep circuit
+Tek r422 2.jpg|R422, compartment open
-Tek 422 vertamp.png|Vertical amplifier circuit
+Black tek 422.jpg|Black 422, panel mount
-Tek 422 inputamp.png|Input amplifier circuit
+Tek 422 triag trace.jpg
-Tek 422 horizamp.png|Horizontal amplifier circuit
+Tek 422 tight beam.jpg|422 trace is sharp
-Tek 422 crt.png|CRT circuit
+Tek_222_wtrace2.jpeg | 422 in ALT
+Tek 422 34.JPG
+Tek 422 342.JPG
 mpf102 cal.jpg
+</gallery>
+=== Internal===
+<gallery>
+8056 mpf102.jpg|[[MPF102]] replacing [[8056]]
+Wellenkino 422.jpg
 Tek 422 front part rear.jpg
 Tek 422 left int.jpg
@@ Line 72: / Line 79: @@
 Tek 422 vert amp2.jpg
 Tek 422 vert input amps.jpg
+</gallery>
+=== Schematic===
+<gallery>
+Tek 422 trigger.png|Trigger circuit
+Tek 422 sweep.png|Sweep circuit
+Tek 422 vertamp.png|Vertical amplifier circuit
+Tek 422 inputamp.png|Input amplifier circuit
+Tek 422 horizamp.png|Horizontal amplifier circuit
+Tek 422 crt.png|CRT circuit
 Tek-422 lvps2.png|ac-dc power supply
 Tek 422 acps.png|ac power supply
-8056 mpf102.jpg|[[MPF102]] replacing [[8056]]
-Wellenkino 422.jpg
-Tek 422 34.JPG
-Tek 422 342.JPG
-Tek r422 1.jpg|R422, compartment closed
-Tek r422 2.jpg|R422, compartment open
-Black tek 422.jpg|Black 422, panel mount
-Tek 422 triag trace.jpg
-Tek 422 tight beam.jpg|422 trace is sharp
 </gallery>
 [[Category:400 series scopes]]