Tektronix 7623, Instruction Manual

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Calibration—7623/R7623 Service
b. CHECK—Vertical trace produced by 7B53A should
align with the vertical center line of the graticule within 0.3
division.
c. ADJUST—Horizontal Centering adjustment R525
(see Fig. 2-6) to position the trace to the vertical center
line.
d. INTERACTION —If R525 is adjusted, re-check step
22.
24. Check/Adjust Horizontal Amplifier Gain and
Low-Frequency Linearity
a. Install the 7A15A in the horizontal compartment and
the 7B53A in the vertical compartment. Set the 7A15A
Volts/Div switch to 0.2 volt/division. Connect a 0.4 volt
square-wave Calibrator signal to the 7A15A; adjust the
Position control to keep the display centered on the
graticule and adjust the Variable Volts/Div control, if
needed, for two-division display.
b. CHECK —Position the two division display horizon­
tally and check for not more than 0.1 division compression
or expansion anywhere within the graticule area. Remove
the 7A15A and install the mainframe standardizer calibra­
tion fixture. Set the Test switch on the calibration fixture
to VERT or HORIZ GAIN.
Fig. 2-6. Location of Horizontal System adjustments (Horizontal
Amplifier board).
h. INTERACTION—If R512 is adjusted, re-check steps
22 through 25.
25. Adjust High-Frequency Timing
a.
Install the 7A15A in the left vertical compartment.
b. Connect the time-mark generator to the input con­
nector of the 7A15A with the 42-inch 50-ohm BNC cable
and the 50-ohm BNC termination.
c. Set the 7853A for auto, external triggering at a sweep
rate of one millisecond/division.
d. Position the display so that the first and ninth traces
are near the far left and right vertical lines of the graticule.
e. CHECK-Deflection between the second and eighth
traces is eight divisions ±0.08 division.
f. ADJUST-Horizontal Gain adjustment R512 (see Fig.
2-5) for exactly eight divisions of deflection between the
second and eighth traces.
g. CHECK-With gain set exactly, all nine vertical traces
align with their respective graticule lines within 0.05
division.
c. Set the time-mark generator for one-millisecond
markers. Set the deflection factor of the 7A15A so the
markers are at least two divisions in amplitude.
d. Set the 7B53A for auto, internal triggering at a sweep
rate of one millisecond/division.
e. Position the first marker to the left vertical line of the
graticule.
f. Set the 7B53A Swp Cal adjustment for one marker
each major graticule division between the first and ninth
lines.
g. Set the time-mark generator for 10-nanosecond
markers.
h. Set the 7B53A for a sweep rate of 0.05 microsecond/
division with the X10 magnifier on; set the deflection
2-18