Set Crt Geom Adj.; Check Distributed Amplifier Bias; Check Vertical Amplifier Balance; Check Vertical Compression Or Expansion - Tektronix 545 Calibration Procedure

7.

SET CRT GEOM ADJ.

Insert from the SQUARE-WAVE CALIBRATOR enough signal so that only the rising and
falling portions of the signal are visible within the graticule.
ITY and TRIGGERING LEVEL controls for a stable display.
not been adjusted so if it is not possible to obtain a stable display, adjust the
TRIG. SENS, and/or TRIGGERING LEVEL CENTERING pot.)
chassis directly below rear handle)
trace.
8.

CHECK DISTRIBUTED AMPLIFIER BIAS

Invert scope and place a voltmeter across the grid lines of the distributed amp­
lifier. Adjust VERTICAL POSITION to the point where there is zero volts from one
grid line to the other.
each tube in the amplifier for at least one volt of bias.
9.

CHECK VERTICAL AMPLIFIER BALANCE

Short crt vertical deflection plates to determine the crt electrical
the grids of the 6DK6'
should not exceed 2 mm in the 6DK6 stage, 1 cm in the 6DJ8 stage, and 1 cm in the
12BY7 stage with the overall amplifier unbalance not to exceed 1.5 cm.
the graticule positioning cam to align the graticule center line with the center
of the usable area of the crt.
10.

CHECK VERTICAL COMPRESSION OR EXPANSION

Position 2 cm of calibrator signal up and down within the graticule lines.
able compression or expansion is ±0.5 mm*
11.

SET VERTICAL GAIN ADJ.

Switch TEST LOAD UNIT to 250:1 and apply a 100 v signal from SQUARE WAVE CALIBRATOR
and adjust AMFL. GAIN for 4 cm of vertical deflection.
TOR to 0.2 v . TEST LOAD UNIT to 1:1 and check for 2 cm of vertical deflection.
12.

CHECK ALTERNATE SWEEP OPERATION

Check scope for ALTERNATE SWEEP operation by switching TEST LOAD UNIT to DUAL TRACE.
Remove the TEST LOAD UNIT and install a 53/5*fK PLUG-IN UNIT.
13.

CHECK SQUARE-WAVE CALIBRATOR AND VOLTS TO MILLIVOLTS DIVIDER.

Check accuracy of SQUARE-WAVE CALIBRATOR voltage steps with the K UNIT VOLTS/CM
step switch. Compare the VOLTS range to the MILLIVOLTS range.
l *f.

ADJUST DC SHIFT COMPENSATION

Vertically deflect the trace with enough dc voltage to move the trace about k cm.
This is a very slow drift and must be watched for a few seconds to see the direc­
tion of drift.
15.

SET TRIGGERING LEVEL CONTROL

Set the trigger controls to + INT and DC, TIME/CM to 100 usee. STABILITY full left
(ccw), but not to PRESET.
set the trigger on LINE, AUTOMATIC and set the sweep TIME/CM switch to 1 MILLISEC.
X2. Use a 10X probe properly adjusted.
zero reference.
aim of TRIGGERING LEVEL pot on scope under calibration and set pot to zero volts.
Physically center knob and tighten set screw,
zero volts during succeeding adjustments.
September, 1959
With the plus probe of the meter, check the cathode of
, 6DJ8's, and the 12BY7's, in that order. The unbalance
s
Set the test scope VERTICAL INPUT to .05 VOLTS/CM. DC,
Connect the probe to the grid end of the k'JOK resistor from the
Adjust GEOM. ADJ.
to obtain minimum curvature of the vertical
Switch SQUARE-WAVE CALIBRA­
Center the trace on the test scope for a
Leave TRIGGERING LEVEL control at
Adjust STABIL­
(The trigger circuit has
(on P & I
center. Short
Adjust
Allow­
5^5 2
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