Tektronix CURVE-TRACER 576 Instruction Manual page 149

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d. Check for the spot horizontally centered on the CRT
graticule .
e. ADJUST -R224, AMP BAL adjustment, on the STEP
GEN circuit board (see Fig. 5-7) if the spot is not centered.
f. Set the Type 576 AMPLITUDE switch to 2 V.
g. Check for the spot horizontally centered on the CRT
graticule.
h. ADJUST -R97, ZERO STEP adjustment, on the
STEP GEN circuit board (see Fig. 5-7) if the display is not
centered.
i. Reset the AMPLITUDE switch to .05 V.
j. Repeat parts b through i until the spot remains
centered when the AMPLITUDE switch is switched
between the .05 V and the 2 V positions.
k. Set the AMPLITUDE switch to 2 V and press the
POLARITY INVERT button.
I. Check for the spot centered horizontally on the CRT
graticule.
m. ADJUST -R 127, INVERT ZERO adjustment, on the
STEP GEN circuit board (see Fig. 5-7) if the spot is not
centered.
22. Adjust Step Amplifier Gain
a. Set the following Type 576 controls to:
VERTICAL
CENTERLINE VALUE
HORIZONTAL
NUMBER OF STEPS
AMPLITUDE
STEP FAMILY
POLARITY INVERT
2A
10
1 V BASE
10
1
v
REP
Released
0
b. Press the Type 576 ZERO button and position the
spot to the center vertical graticule line with the FINE
POSITION controls.
c. Release the ZERO button.
®
Performance Check/Calibration-Type 576
d. Check for the 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. 5-7) if the spot is not
centered.
f. Press the AID OFFSET button.
g. Check for the 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. 5-7) if the spot
is not centered.
i. Set the CENTERLINE VALUE switch to 0 and press
the OPPOSE OFFSET button.
j. Check for the spot on the center vertical graticule line
±2 divisions (±2%).
k. ADJUST -R85, OPPOSE OFFSET adjustment on the
STEP GEN circuit board (see Fig. 5-7), if the spot is not
centered.
23. Adjust Current Balance
0
a. Set the following Type 576 controls to:
VERTICAL
HORIZONTAL
DISPLAY OFFSET Selector
CENTERLINE VALUE
AMPLITUDE
OFFSET
Terminal Selector
STEP GEN
.1 V BASE
HORIZ X1
5
50 ]JA
ZERO
EMITTER GROUNDED
BASE TERM OPEN
(OR EXT)
b. Connect a 1 kn resistor between the base (B) and the
emitter (E) jacks (right side) of the Standard Test Fixture.
c. Connect a shorting strap between the STEP GEN
OUTPUT connector on the Standard Test Fixture and the
base connector.
d. Set the LEFT-OFF-RIGHT switch to RIGHT and
position the tenth spot to the intersection of the tenth
horizontal and center vertical graticule lines.
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