Tektronix 310A, Instruction Manual, Page: 59 / 132

Performance Check/Calibration—Type 310A
Fig. 5 3. Lo catio n o f high-voltage test p o in t and ad justm ent (right
side).
d. C H E C K -V a ry the autotransformer o u tp u t voltage
throughout the regulating range fo r which this instrument is
wired and check for less than ±49 volts change in the high
voltage o u tp u t level. Also set the IN TEN SITY control fu lly
clockwise at m inimum line voltage and fu lly counterclock­
wise at maximum line voltage; check that regulation
remains w ith in given limits.
f. CHECK—Test oscilloscope display for less than one
division vertical deflection (10 m illivolts ripple) while
varying the autotransform er o u tp u t voltage throughout the
regulating range.
g. Connect the probe tip to the +300-volt test p oint (see
Fig. 5-2A). Connect the probe ground lead to the Type
310A chassis near the test point.
h. C H E C K -T est oscilloscope display fo r less than four
divisions vertical deflection (40 m illivolts ripple) while
varying the autotransformer o u tp u t voltage throughout the
regulating range fo r which this instrument is wired.
i. Return the autotransformer to the center voltage o f
the regulating range. (If the line voltage is near the center o f
the regulating range, the Type 310A can be connected
d irectly to the line; otherwise, leave the instrument con
nected to the autotransformer for the remainder o f this
procedure)
j. Disconnect all test equipment.
6. Check/Adjust DC Balance
a. Connect the vertical INPUT connector to one o f the
ground posts on the fron t panel w ith the 18-inch BNC-to
banana plug patch cord.
CAUTION
If a spot or trace appears on the screen when the
IN TEN SITY control is turned clockwise, position it
o ff the viewing area to protect the CRT phosphor.
a IN T E R A C T IO N -M a y affect operation o f all circuits
w ith in the Type 310A.
f. Disconnect the DC voltmeter.
5. Check Low-Voltage Power Supply Ripple
a. Connect the IX probe to the test oscilloscope input
connector.
b. Set the test oscilloscope for a vertical deflection
factor o f 10 m illivolts/division, AC coupled, at a sweep rate
o f five milliseconds/division.
c. Connect the probe tip to the -1 5 0 -v o lt test p oint
(see Fig. 5-2A). Connect the probe ground lead to the Type
310A chassis near the test point.
d. C H EC K-Test oscilloscope display for less than one
division vertical deflection (10 m illivolts ripple) while
varying the autotransformer o u tp u t voltage throughout the
regulating range fo r which this instrument is wired.
b. Turn the TRIG LEVE L and S T A B IL IT Y controls
fu lly clockwise.
c. Advance the IN TE N S ITY control u n til a trace is
visible. If the trace is not visible w ith the IN TEN SITY
control set near midrange, preadjust the DC Bal adjustment
to bring the trace on screen (V E R T IC A L POSITION con­
trol must be set to midrange).
d. Adjust the FOCUS control fo r as well-focused a dis
play as possible (trace may not focus well since the ASTIG
adjustment has not been performed yet).
e. Position the trace to the center horizontal line w ith
the V E R T IC A L POSITION control.
f. C H E C K -R o ta te the Variable V O LT S /D IV control
throughout its range. Trace should not move more than one
division vertically.
g ADJUST DC Bal adjustment, R344 (see Fig. 5 4),
fo r m inim um trace shift as the Variable V O LT S /D IV con­
tro l is rotated.
h. Return the Variable V O LT S /D IV to the C A L I­
BRATED position.
c Connect the probe tip to th e +100-volt test p o in t (see
Fig. 5-2A). Connect the probe ground lead to the Type
310A chassis near the test point.
7. Check/Adjust Preset Stability
a. Set the Trigger Coupling-Mode switch to Auto.
5-9