422: Difference between revisions

Revision as of 09:42, 13 May 2019

{{{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

Trigger circuit
Sweep circuit
Vertical amplifier circuit
Input amplifier circuit
Horizontal amplifier circuit
CRT circuit
ac-dc power supply
ac power supply
MPF102 replacing 8056
R422, compartment closed
R422, compartment open
Black 422, panel mount
422 trace is sharp

@@ Line 13: / Line 13: @@
 * [http://w140.com/tek_422_sn_20000_up.pdf Tektronix 422 Manual for Serial Numbers 20,000 and up (PDF)]
 * [http://w140.com/tek_422_product_reference_book.pdf Tektronix 422 Product Reference Book (PDF)]
 * [[Media:070-0434-02.pdf|Tektronix 422 Manual (PDF, OCR, low quality scan, bad-OCR)]]
 * [[Media:070-0528-00.pdf|Tektronix 422 Manual, AC power supply (PDF, OCR)]]
-* [[Media:tek_422_ac/dc.pdf|Tektronix 422 Manual with AC/DC Power Supply (PDF, OCR)]]
 * [[Media:070-0895-00.pdf|Tektronix 422 Manual for Serial Numbers 20,000 and up (PDF, OCR, bad-OCR)]]
 * [[Media:tek_422_prb.pdf|Tektronix 422 Product Reference Book (PDF, OCR)]]