Model 122A Sect. IV Page 1
SECTION IV
MAINTENANCE
I-1 INTRODUCTION AI 4 YZE P. RTICULAR INSTRUMENT. THIS
EXTRA DATA CANNOT BE CONSIDERED AS
This section contains instructions for testing, ad- SPECIFICATIONS.
justing, and trouble-shooting the Model 122A Os-
cilloscope. In general, the Model 122A can be divided into
sections with the parts for any particular section
The Front Panel Operational Check, paragraph 4-2, located behind the front panel controls for that
is a fast method of checking the operation of the section. The power supplies are in the rear and
instrument. The Trouble-Shooting Procedure, on the top chassis brace. Thematerial that follows
paragraph 4-5, is a rapid means of isolating a is divided into sections according to circuit
section of the instrument that is not functioning. functions. Each section has a complete set of
The Condensed Test and Adjustment Procedure, adjustment instructions.
paragraph 4-6, is a fast method of checking the
basic adjustments of the instrument. The Complete The following test equipment is used for testing
Test Procedure, paragraph 4-7, is an expansion of and adjusting the Model 122A Oscilloscope during
the condensed test and adjustment procedure. manufacture. Equivalent test equipment may be
used for testing purposes.
Paragraphs 4-3 and 4-4 contain information on
I removing the cabinet and replacing tubes. 1) ?Reference Oscillator? with frequency range of
400 cps to 500 kilocycles, and adjustable output
Schematic Diagrams and the Table of Replaceable 5 millivolts to 20 volts, such as @Model 200CD
Parts are located at the end of this section. Wide Range Oscillator.
2) ?Reference VTVM? with 1% accuracy, 400 cps
Standard, readily available components are used to 500 kilocycles frequency range, and 50 milli-
for manufacture of @ instruments whenever pos-
sible. Special components are available directly volts to 60 volts voltage range, suchas the @Model
from the @ factory. Perhaps the most convenient 400H Vacuum Tube Voltmeter.
source for spare or replacement parts is your 3) ?Marker Generator? with frequency range of
local @ representative who maintains a parts 200 kilocycles to 1 cycle per second in decade
stock for your convenience. When ordering parts,
please specify instrument model and serial number steps and an accuracy of *0.3%, such as the
plus the component description and stock number Tektronix 180 Time Mark Generator.
appearing in the Table of Replaceable Parts. 4) ?Calibration Generator? furnishing lOOv dc and
100 v ac at 400 or 1000 cps, all voltages with an ac-
Your local @ representative also maintains com- curacy of * 0.25%. In addition the ?Calibration Gen-
plete facilities and specially trained personnel to erator? must have an attenuator which will reduce
assist you with any engineering, application, test, the voltage to 20 millivolts in a 1-2-5 times atten-
or repair problems you may have with @instru- uation with an accuracy of *0.25%. The @ Specifi-
ments . cation 23678 Voltmeter Calibration Generator will
meet these specifications.
SPECIFICATIONS FOR THE @ 122A OSCILLO-
SCOPE ARE GIVEN IN THE FRONT OF THIS 5) ?Adjustable Attenuator? having adjustable db
MANUAL. THE SERVICE PROCEDURES THAT steps from 1 to 110 db. Use an @ Model 350A
FOLLOW CONTAINEXTRADATATOHELPYOU Attenuator or equivalent.
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