Tektronix 7B92 Instruction Manual page 33

Calibration-7B92 Service
double triggering or defocusing of sine waves (MAIN
TRIGGERING LEVEL control may be adjusted as neces-
sary for a stable display l-
j_ ADJUST -Vary the high-frequency generator from
500 megahertz to 100 megahertz and from 100 megahertz
to 500 megahertz_ Repeat the adjustment of R740, R750,
and R959 for a stable CRT display with no defocusing or
double triggering_
k_ INTERACTION-The adjustment of R959 may
affect the adjustment of R940 and R950 (Calibration step
12) and R364 (Calibration steps 1 and 26)_
L Change the 7 A 19 Volts/Div switch to _1 V and set the
MAIN TR IG SOURCE switch to EXT_
m_ Set the high-frequency generator for a five-division
display (500 millivolts) at 500 megahertz_
vn- CHECK-Stable CRT display can be obtained with
the MAIN TRIGGERING COUPLING switch set to AC, AC
LF REJ, and DC for both the
(+)
and (-) SLOPE_
vo- CHECK-Vary the high-frequency generator from
500 megahertz to 100 megahertz and from 100 megahertz
to 500 megahertz_ CHECK for stable CRT display with no
double triggering or defocusing (MAIN TRIGGERING
LEVEL control may be adjusted as necessary for a stable
displayl-
p_ CALIBRATION-If the 7B92 does not meet the
requirements given in parts nand
0,
check the adjustments
of R740, R750 and R959_
V12. Check/Adjust Delayed Triggering TD Bias
(R940, R950)
a_ Set the high-frequency generator and the 7A19
Volts/Division switch for a one-division display at 500
megahertz_
b_ Change the following control settings:
7B92 Time Base
Main Triggering
SOURCE
LEVEL
Delayed Triggering
LEVEL
4-12
Scans bv Outsource-Options =>
INT
Adjust for TRIG'D
light on
OUT -DL Y'D SWP
TRIGGERABLE
c_ Rotate the Delayed Triggering LEVEL control for a
stable delayed sweep display_
NOTE
If a display cannot be obtained at any setting of the
Delayed Triggering LEVEL control, check the pre-
liminary adjustment of R940 and R950 (Calibration
step 1) and R920 (Calibration step 4).
Vd. CHECK-Stable delayed sweep display can be
obtained with the Delayed Triggering COUPLING switch
set to AC and DC for both the (+) and (-) SLOPE (Delayed
Triggering LEVEL control may be adjusted as necessary for
a stable display).
e. ADJUST -R950, Delayed Sweep Start TD Bias, to
observe a slight shift or jump of the delayed sweep trace.
Adjust R950 10 degrees clockwise from the observed shift.
f. ADJUST -R940, Delayed Arming TD Bias, to remove
any double triggering or defocusing from the delayed sweep
display.
Vg. CHECK-Rotate the DELAY TIME MULT dial
throughout its range and check for no double triggering or
defocusing of sine waves.
h. INTERACTION-Repeat the adjustment of R940
and R950 as necessary. It may be necessary to check the
adjustment of R920 Calibration step 4).
i. Remove the BNC cable from the MAIN TR IG IN
connector and connect it to the DLY'D TRIG IN
connector.
j. Set the 7 A 19 Volts/Division switch to .1 V. Set the
high-frequency generator for a five-division display
(500 mV) at 500 megahertz.
k. Change the Delayed Triggering SOURCE switch to
EXT.
vI. CHECK-Stable delayed sweep display can be ob-
tained with the Delayed Triggering COUPLING switch set
to AC and DC for both the
(+)
and (-) SLOPE (Delayed
Triggering LEVEL control may be adjusted as necessary for
a stable display).
®