SECTION 5
CALIBRATION
Introduction
The Type 544 Oscilloscope is a stable instrument which will
provide many hours of trouble-free operation. However, to
insure measurement accuracy, it is suggested that you recali
brate the instrument after each 500 hours of operation or
every six months if used intermittently. It will also be neces
sary to recalibrate certain sections of the instrument when
tubes, transistors, or other components are replaced.
The steps in the following procedure are arranged in the
proper order for complete recalibration so as to avoid unnec
essary repetition.
NOTE
This procedure is a combination performance check
and adjustment procedure. The first part of the step
title is the name of the check or adjustment and the
latter portion refers to the pertinent circuit diagram.
Tables 5-4, 5-5, 5-9, and 5-10 list the front-panel
control settings at particular points in the procedure.
These tables serve two purposes: (1) To quickly
check your own setup, and (2) to enable you to
start in the "middle" of the procedure when it is
necessary to recalibrate a certain portion of the in
strument. For example, Table 5-4 shows the front-
panel setup at the completion of step 12e. Using
these same control settings this can be the starting
point for recalibrating the Sweep Trigger circuit.
Th us, the table eliminates the need to go back any
further towards the beginning of the procedure to
find out what the front-panel setup should be.
Unless otherwise stated, all resistances, voltages,
and waveforms are measured with respect to chassis
ground.
EQUIPMENT REQUIRED
The following equipment, or its equivalent, is necessary for
complete calibration of the Type 544 Oscilloscope:
(1) Low-Bandwidth Test Oscilloscope with a IX attenuator
probe.
Description: Bandwidth, dc to 300 kc or better; cali
brated vertical deflection factor of 5 mv/cm.
Purpose: To check low-voltage power supply output rip
ple amplitude.
(2) Test load unit, Tektronix Type TU-7. Contains a pulse
generator capable of producing pulses with a risetime
of 3 nsec or faster. This multi-purpose test-load unit is
the only plug-in needed to perform a complete calibra
tion of the Type 544 Oscilloscope.
(3) Time Mark generator, Tektronix Type 180A. Markers re
quired at 1 and 5 seconds; 500, 100, 10, 5, and 1 milli
seconds; 500, 100, 50, 10, 5, and 1 microseconds; 5, 10,
and 50 megacycle sine waves. 10/isec trigger pulse out
put required. All outputs must have a time accuracy of
at least 0.1%.
(4) VOM (Volt-Ohm-Milliammeter) DC sensitivity of at least
20,000 ohms per volt.
Calibrated for an accuracy of at least 1% at —150,
+ 100, +225, and +350 volts; at least 5% at -—1850
volts.
(5) Variable autotransformer (e.g. Powerstat or Variac).
Required specifications: a rating of at least 590 volt-
amperes; output voltage range covering the operating
range of the oscilloscope under test.
(6) An rms-calibrated ac voltmeter. Required specifications:
a range of 0-150 volts (0-300 volts if the oscilloscope is
wired for 230-volt nominal line-voltage operation).
(7) Two coaxial cables, 50-ohm nominal impedance, 42"
long, with BNC plug-connectors on each end. Part No.
012-057.
(8) Power cord adapter for connecting the 3-wire oscillo
scope power cord to a 2-wire receptacle. Part No.
103-013.
(9) Adapter, single binding post fitted with a BNC plug.
Part No. 103-033.
(10) Coaxial connector adapter with BNC-jack and UHF-
plug connector fittings. Part No. 103-015.
(11) Jumper clip lead, about 4" long. Equipped with minia
ture alligator clips on each end.
(12) Two interconnecting leads, 18" long, red, with combina
tion plug-and-jack banana type connectors on each end.
Type PC-18R. Part No. 012-031.
(13) BNC T connector. Fits one BNC jack and accepts two
BNC plugs. Part No. 103-032.
(14) Miscellaneous Items
1 —Screwdriver, 3/is" wide bit, shank about 3" long.
1 —Screwdriver, %2" wide bit, shank about 2" long.
1—Jaco No. 125 insulated low-capacitance-type screw
driver with a I'/j" long shank and %" wide metal
tip. Total length is 5". Part No. 003-000.
1—Low-capacitance alignment tool, consisting of a
handle (Part No. 003-307), a gray nylon insert with
a metal screwdriver tip (Part No. 003-334), and %4 "
hexagonal wrench insert (Part No. 003-310).
1 —Hexagonal wrench, '/i6'\ Purpose: To reposition, if
necessary, the TRIGGERING LEVEL control knob.
PRELIMINARY PROCEDURE
1. Remove the side and bottom panels from the oscilloscope.
2. Insert the Type TU-7 (item 2) in the oscilloscope vertical
plug-in compartment.
3. Set the Type TU-7 Test Function switch to the Low Load
position.
5-1
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