Tektronix 475A - Operators Adjustments and Checks; Trace Rotation; Probe Compensation

OPERATOR’S ADJUSTMENTS AND
CHECKS
To verify measurement accuracy, perform the follow-
ing checks and adjustments before making a measure-
ment. See the Calibration section of the Service manual
for calibration information.
Trace Rotation Adjustment
Normally not required. Obtain a Normal Sweep Display
using only steps 1 through 3. Set the CH 1 input Coupling
switch to GND to display a free-running trace with no
vertical deflection. Adjust the TRACE ROTATION (screw-
driver adjustment located below the crt graticule) to align
the trace with the center horizontal graticule line.
Probe Compensation
Miscompensation is one of the greatest sources of
operator error. Most attenuator probes are equipped with
adjustments to ensure optimum measurement accuracy.
Probe compensation is accomplished as follows:
Obtain a Normal Sweep Display presentation of the
calibrator square-wave voltage. Set the appropriate
VOLTS/DIV switch to .1 V position and the Input coupling
to DC. Check the waveform presentation for overshoot or
rolloff, and if necessary, readjust compensation for flat
tops on the waveforms. See Fig. 11. Refer to probe manual
for method of compensating the probe being used.
PERI TT
me ee ee
100 '**
30
OVER COM-
PENSATED
| (OVERSHOOT)
AE AEE RSA
UNDER COM-
PENSATED
IROLLOFFI
465/DM-0-5
Fig. 11. Probe compensation.
© 475A/DM44 Operators 29