Tektronix TU-7, Инструкция по эксплуатации

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SECTION 5
CALIBRATION
General Information PRELIMINARY INSTRUCTIONS
The Type TU-7 does not require frequent recalibration,
however, the calibration should be checked at regular inter­
vals to insure that it is operating properly and accurately.
In addition, calibration should be checked after tubes or
transistors have been replaced or repairs have been made.
A complete procedure is provided in this section for checking
and adjusting the Type TU-7.
In the instructions that follow, the steps are arranged
in convenient sequence to avoid unnecessary repetition.
Individual steps can be performed out of sequence, but the
equipment connections and control settings in previous steps
will need to be noted. If the DRIVE BAL control (step 12)
is adjusted, the PULSE DC LEVEL adjustment (step 13) must
be checked.
Equipment Required
The following items of equipment or equivalent are re­
quired for a complete calibration of the Type TU-7.
1. Indicator oscilloscope, Tektronix 530-, 540-, or 550-
Series. Must operate properly and be calibrated for
vertical gain and sweep timing.
2. Test oscilloscope, laboratory-type. Dc to at least 1 me
bandpass, ac and dc input coupling, 0.02 to 20 volfs/cm
input deflection factor.
3. 1 OX probe, for test oscilloscope. High impedance input.
4. 42-inch 50-ohm coaxial cable with BNC connectors
[Tektronix part no. 012-057).
5. Amplitude calibrator. 1 kc square-wave output, am­
plitudes from at least 0.5 volt to 100 volts peak-fo-peak,
accuracy within 3%. The oscilloscope Calibrator may be
used.
1. Lay the indicator oscilloscope (item 1 under "Equipment
Required” ) on its right side. If rackmounfed, leave oscillo­
scope upright.
2. Remove the oscilloscope bottom panel and left side panel.
3. Connect the test instruments to the power line.
4. Turn on all test instruments except the indicator oscillo­
scope.
5. Set the indicator oscilloscope front-panel controls as fol­
lows:
Horizontal Display Time Base A
Time/Cm 1 mSEC
Triggering + Internal, Ac
6. Set the sampling oscilloscope controls as follows:
Time/Cm 1 nSEC
Triggering -(-Internal
7. Set the Type TU-7 controls as follows:
NOTE
Do not insert the Type TU-7 into the ind icato r
oscilloscope until instructed later in the procedure.
TEST FUNCTION
VARIABLE
VERTICAL POSTION
AMPLITUDE
REPETITION RATE
LOW LOAD
Centered
Centered
Centered
MED
PROCEDURE
6. Dc voltmeter. 20,000 ohms/volt impedance, 0.5% ac­
curacy at 67.5-voIt reading.
7. Ohmmeter or multimeter. Resistance scale of 1 ohm, 10
ohms, 1,000 ohms, and 100,000 ohms, 3% accuraccy.
8. Oscilloscope, sampling-type, dual-trace. 50-ohm inputs
with GR connectors, at least 10 to lOOmv/cm input de­
flection factor, bandpass to 1 gc [gigacycle — I0 9cps),
capable of operating in differential mode. This instru­
ment and the following two items are required only for
checking the risetime of the Pulse Generator output.
9. Two 50-ohm coupling capacitors (874-K), with GR con­
nectors, for sampling oscilloscope. (Tektronix part no.
017-028).
10. 16-pin plug-in extension, specially modified for checking
Pulse Generator output. Construction of the extension is
illustrated in Fig. 5-1.
1. Check Resistances
NOTE
This step is required only if the instrument has
been repaired or has been malfunctioning.
a. With the aid of Table 4-1, measure resistance from
chassis ground to the interconnecting plug pins.
2. Check Protection Diode— Pulse Generator
a. Set the ohmmeter to the 1-ohm scale and check the
in-circuit resistance across D54 for approximately
5 ohms in ore direction; infinite in the other direc­
tion. See Fig. 5-2 for location of D54.
Check + 2 2 5 V Output
a. Insert the Type TU-7 into the indicator oscilloscope.
5-1