PART II—SHORT-FORM CALIBRATION
Calibration—475
Introduction
The following procedure is intended to be used as
guidelines for calibration of the 475 by experienced
technicians familiar with the instrument. Only essential
information is given. Test Equipment Required is the same
as that given for Part III—Calibration.
Preliminary Procedure for Short-Form Calibration
NOTE
This instrument shou/d be adjusted at an ambient
temperature of +25°C (±5°C) for best overall
accuracy.
1. Remove the dust cover from the 475.
2. Connect the 475 to the autotransformer and set the
line voltage to 115 VAC.
3. Set the controls as given under Preliminary Control
Settings (given prior to Part I—Performance Check). Allow
at least 20 minutes warmup before proceeding.
NOTE
Titles for external controls of this instrument are
capitalized in this procedure (e.g., INTENSITY).
Internal adjustments are initial capitalized only (e.g..
Grid Bias).
POWER SUPPLIES and
DISPLAY CALIBRATION
1. Low Voltage Power Supplies
a. A D JU ST- +50 V supply, R1430, ±0.5%.
b. Check—+110 V supply, ±3%.
c. Check—+15 V supply, ±1.5%.
d. Check—+5 V supply, ±1.5%.
e. Check
-----
15 V supply, ±1.5%.
f . Check
-----
8 V supply, ±1.5%.
g. Check ripple on supplies (except +110V supply) is
2 mV P-P maximum; +110 V supply ripple is I V P-P
maximum.
h. Check regulation between 126.5 V and 103.5 V line.
i. Check LOW LINE indicator comes on below
103 VAC.
2. High Voltage Power Supply
—2450 volts, ±49 volts.
3. Adjust CRT Grid Bias
a. TRIG MODE to NORM.
b. Connect DC Voltmeter to TP1364 and adjust INTEN
SITY for a reading of +15 volts.
c. ADJUST—CRT Grid Bias, R1375, for dimmest dot.
4. Check Display Controls
a. ASTIG
b. SCALE ILLUM
c. FOCUS
d. INTENSITY
5. Adjust Trace Alignment
a. Connect time markers to CH 1 input.
b. ADJUST—TRACE ROTATION to align trace with
center horizontal line.
c. ADJUST—Y Axis Alignment, R1385, to align center
time marker with the center vertical line.
5-14
d. Check for no more than 0.1 division curvature.
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