Tektronix 556 Instruction Manual page 144

Calibration— Type 556
25. Check Alternate Trace Operation
a. Connect the BNC T connector to the Type 556 CAL OUT
connector. Connect two 50 f l cables from the T connector to
the Ext Input connectors on the right and left test load units.
b. Set the AMPLITUDE CALIBRATOR to 10 VOLTS, and set
the Test Function switches on both Test Load units to Alternate.
c. Check— Two Traces on the Upper Beam display, with
the calibrator signal appearing on only one trace.
d. Rotate the A TIME/CM switch through all positions from
1 mSEC to .1 /xSEC, checking for two traces on the Upper
Beam display for all positions.
e. Repeat steps (c) and (d) for the Lower Beam, checking
for two traces in all positions of the B TIME/CM switch from
1 mSEC through .1 fiSEC.
f. Change the Upper Beam DISPLAY switch to LEFT PLUG­
IN B.
g. Rotate the B TIME/CM switch through all positions from
1 mSEC to .1 fiSEC.
h. Check— Two traces displayed by each beam in all
positions of the B TIME/CM switch.
i. Change the Upper Beam DISPLAY switch to RIGHT
PLUG-IN A.
j. Rotate the A TIME/CM and B TIME/CM switches through
all positions from 1 mSEC to .1 fiSEC, keeping the A and B
TIME/CM settings the same.
W ith the Upper Beam DISPLAY switch in the RIGHT
PLUG-IN A position, m ultiple traces w ill a p p e a r on
b oth displays fo r some o f the switch positions. This
condition is norm al.
k. Check— Two traces on each beam at all positions of
the TIME/CM switches.
. Change the Upper Beam DISPLAY switch to RIGHT
l
PLUG-IN B.
m. Rotate the B TIME/CM switch through all positions from
1 mSEC to .1 /xSEC.
n. Check— Two traces displayed by each beam at all
settings of the TIME/CM switches from 1 mSEC through .1
/xSEC.
SN 2000-u p only
o. Set the Lower Beam DISPLAY switch to A.
6 -2 6
NOTE
p. Rotate the A TIME/CM and
through all positions from 1 mSEC to .1 fiSEC, keeping the A
and B TIME/CM settings the same.
q. Check— Two traces on each beam at all positions of
the TIME/CM switches.
r. Return the Lower Beam DISPLAY switch to B.
s. Remove the AMPLITUDE CALIBRATOR signal from both
plug-ins.
26. Check Multi-Trace Chopping Transient
Blanking
a. Change both test load unit Test Function switches to
Chopped.
b. Set the Upper Beam DISPLAY switch to LEFT PLUG-IN
A.
c. Set both TIME/CM switches to 5 /tSEC.
d. Adjust the A and B Triggering LEVEL controls for stable
displays on both teams.
e. Change the Upper Beam CRT Cathode Selector switch
(on rear panel) to UPPER BEAM CHOPPED BLANKING.
f. Check— Disappearance o f fast chopping transients (ver­
tical lines) on the Upper Beam display.
g. Repeat steps (e) and (f) with the Upper Beam DISPLAY
switch in the LEFT PLUG-IN B, RIGHT PLUG-IN A, and
RIGHT PLUG-IN B positions.
W ith the U pper Beam DISPLAY switch in the RIGHT
PLUG-IN A p ositioin, the A T riggering SOURCE
switch should be changed to RIGHT fo r th a t one
position o n ly.
h. Change the Lower Beam CRT Cathode Selector switch
(on rear panel) to LOWER BEAM CHOPPED BLANKING.
i. Check— Disappearance of fast chopping transients on
the Lower Beam display.
SN 2000-u p only
j. Set the Lower Beam DISPLAY switch to A and repeat
steps (h) and (i).
k. Return the Lower Beam DISPLAY switch to B.
. Reset both CRT Cathode Selector switches to EXTERNAL
l
CRT CATHODE.
m. Disconnect the coaxial cables and BNC T connector.
B TIME/CM switches
NOTE