Tektronix CURVE-TRACER 576 Instruction Manual page 173

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j. Set the AMPLITUDE switch to 2 V and press the
POLARITY INVERT button.
k. Check for spot centered horizontally on the CRT
graticule.
I. ADJUST -R127, INVERT ZERO adjustment, on the
STEP GEN circuit board (see Fig. 1-7) if the spot is not
centered.
14. Adjust Step Amplifier Gain
a. Set the following Type 576 controls to:
VERTICAL 2 A
CENTERLINE VALUE 10
HORIZONTAL 1 V BASE
NUMBER OF STEPS 10
AMPLITUDE 1 V
STEP FAMILY REP
POLARITY INVERT Released
b. Set the Calibration Fixture Step Generator switch to
1
v.
c. Press the Type 576 ZERO button and position the
spot to the center vertical graticule line with the FINE
POSITION controls. Release the ZERO button.
d. Check for spot on the center vertical graticule line ±2
divisions (±2%).
e. ADJUST -R113, STEP AMP GAIN adjustment, on
the STEP GEN circuit board (see Fig. 1-7) if the spot is not
centered.
f. Press the AID OFFSET button.
g. Check for spot on the center vertical graticule line ±2
divisions (±2%).
h. ADJUST -R86, AID OFFSET adjustment, on the
STEP GEN OFFSET circuit board (see Fig. 1-7) if the spot
is not centered.
i. Set the CENTERLINE VALUE switch to 0 and press
the OPPOSE OFFSET button.
j. Check for spot on the center vertical graticule line ±2
divisions (±2%).
ADD AUG 1984
Adjustment-Type 576
k. ADJUST -R85, OPPOSE OFFSET adjustment on the
STEP GEN circuit board (see Fig. 1-7) if the spot is not
centered.
15. Adjust Current Balance
a. Set the following Type 576 controls to:
VERTICAL
HORIZONTAL
DISPLAY OFFSET
Selector
CENTERLINE VALUE
AMPLITUDE
OFFSET
STEP GEN
.1 V BASE
HORIZ X1
5
50 pA
ZERO
b. Set the following Calibration Fixture controls to:
Step Generator
Step Generator
Loads
50 pA
1 K Collector Short
c. Position the tenth spot to the intersection of the
tenth horizontal and center vertical graticule lines.
d. Set the DISPLAY OFFSET Selector switch to
HORIZ X10.
e. Reposition the spot to the intersection of the tenth
horizontal and center vertical graticule line.
f. Set the Calibration Fixture Step Generator Loads
switch to 1 K + 18 K.
g. Check for spot centered horizontally.
h. ADJUST -R243, OUTPUT Z adjustment, on the
STEP GEN circuit board (see Fig. 1-7) if the spot is not
centered.
i. Turn the Step Generator Loads switch back and forth
between the 1 K Collector Short and the 1 K + 18 K
positions and check for no movement of the spot between
the two positions.
Control Settings (Partial List)
VERTICAL 1 pA
DISPLAY OFFSET
Selector
CENTERLINE VALUE
VARIABLE COLLECTOR
SUPPLY
POLARITY
MODE
VERT X10
0.0
Fully Clockwise
+(NPN)
DC (ANTI LOOP)
A-15