Tektronix 3B5, Instruction Manual

Page: 126 / 187

Calibration —Type 3B5
c. Set the Trigger Function switch to EXT-DC.
d. Set the LEVEL control for a stable display,
e. CHECK —Normal and magnified timing accuracy and
correct readout-panel indications in all positions of the MAN ­
UAL TIME/DIV switch. Switch settings, time-mark generator
output, readout-panel indications and tolerances are given
in Table 6-1. First check timing and readout with the DLY'D
SWP MAG switch at OFF; then at X10 and X 1 00 (readjust
LEVEL control as necessary to maintain a stable display).
Also check that the MAG'D SWP readout is on when the
DLY'D SWP MAG switch is set to X10 or X00. Check
timing accuracy between the first and ninth graticule lines.
A typical CRT display is shown in Fig. 6-22.
CAUTION
To prevent permanent damage to the CRT phos ­
phor, either reduce the trace intensity at slow
sweep rates to a level which does not produce a
halo around the spot, or position the baseline of
the marker display below the viewing area.
f. Disconnect the trigger cable.
Test
oscilloscope
system
Time-mark
generator
Indicator
oscilloscope
Rigid plug-in
extender
1
Circuit-card
extender
BNC to
alligator
clips adapter
Remote-seeking
probe
50-Ohm
BNC termination
Fig. 6-23. Initial test equipment setup for steps 22—30.
Control Settings
Type 3B5
MODE MAN
POSITION Midrange
DLY ’ D SWP MAG
OFF
DELAY 0.00
MANUAL TIME/DIV 1 ms
VARIABLE CAL
Trigger Function
LEVEL
SLOPE
INT-AUTO
Midrange
+
Amplifier Unit
Position
Input Coupling
Volts/Division
Mode
Midrange
DC
0.5 Volts
Manual
6-22