Tektronix Type 82 PLUG-IN Instruction Manual page 40

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Fig. 4-11. Checking X1 voltage gain. Set GAIN switch to X1 and V/CM switch to 1.
2. Connect a 30" plug-in cable extension between the Type
82 and the Type 580-Series Oscilloscope.
3. Apply a 2-volt peak-to-peak calibrator signal from the
Type 580-Series Oscilloscope to the appropriate INPUT con-
nector of the Type 82. Also, apply the calibrator signal to
the External Trigger input connector on the test oscilloscope.
(Use items 6 and 7 in the Test Equipment list for this purpose.}
4. Connect a third lead (item 8} between the test oscilloscope
ground terminal and the Type 82 ground.
5. Set the test oscilloscope input coupling switch to AC.
6. Touch the tip of the probe to the CAL. OUT connector on
the Type 580-Series Oscilloscope. Set the front-panel controls
on the test oscilloscope to display one or two cycles of the
calibrator waveform. (Use a sweep rate of 0.1 millisec/cm
or 0.2 millisec/cm.) Be sure to set the test oscilloscope trig-
gering controls for external triggering and to display the
first Yo-cycle of the waveform as positive-going. The dis-
played waveform will then correspond to the input waveform
polarity as shown in Fig. 4-11 and 4-12. Disconnect the
7. Touch the probe tip to the desired test point in the Type
82 circuitry. Set the test oscilloscope Volts/Cm switch to
obtain a suitable amplitude display.
8. Check amplitude and phase of the waveform. Disconnect
the probe.
9. Set the test oscilloscope input coupling switch to DC.
(Preset the test oscilloscope Volts/Cm switch such that the
expected dc voltage to be measured in step 10 will keep
the trace within the graticule-marking area.) Ground the
probe tip to the Type 82 chassis and position the trace to
establish a zero reference point.
4-16
10. Touch the probe tip to the same test point you used
in step 7 of this procedure. Measure the dc level from the
reference point established in step 9 to the same dc-level
point as indicated on the waveform drawing. Disconnect the
probe.
11. Continue on to the next test point and repeat steps 7
through 10 until you reach a test point where an abnormal
indication is obtained. Then proceed with detailed trouble-
shooting checks to find the cause of the trouble. Such
checks usually consist of transistor or tube substitution, and
voltage and resistance checks.
If you have replaced a defective soldered-in type of com-
ponent and substituted tubes or transistors, return the good
tubes or transistors to their original sockets. Such a proce-
dure, if followed, results in less recalibration of the Type 82
upon completion of the servicing.
C. Checking Square-Wave Response
In general, the best way to isolate square-wave distortion
trouble is to go to the Calibration section of this manual after
you have checked the symptoms given in Table 4-5. The dis-
tortion symptoms listed in the table show how to localize the
trouble and the probable causes. The calibration section de-
scribes the proper setup needed to check square-wave re-
sponse and how to make the compensation adjustments
properly. If you perform steps 24 through 29 in the proce-
dure, they will furnish you an orderly approach for isolating
a poor transient-response type of trouble.
Besides the usual causes of distortion given in Table 4-5,
other causes can be found only by careful, detailed, voltage
and resistance checks. If a component is suspected as a
possible cause substitution may prove the best method for