Tektronix 7623, Instruction Manual

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Calibration —7623/R7623 Service
CALIBRATOR
[Equipment Required
3. 7B53A plug-in unit
1. Precision DC voltmeter 4. BNC to pin-jack cable
2. 7A15A plug-in unit
5. Three-inch screwdriver
Control Settings
Set the controls as given in the Preliminary Control
Settings.
30. Adjust Calibrator Output Voltage
a. Change jumper P1066 (see Fig. 2-8) to the DC
position.
b. Connect the precision DC voltmeter between the 4 V
and GND pin jacks.
c. CHECK-Meter reading; 4 volts ±0.04 volt (within
±0.08 volt if this measurement is made outside the +15°C
to +35°C range).
d. ADJUST—4 Volts adjustment R1077 (see Fig. 2-8)
for a meter reading of exactly 4 volts.
Place jumper
here for one
kilohertz output
Place jumper Calibrator
here for DC output Amp. Adjustment
FRONT OF INSTRUMENT
Fig. 2-8. Location of Calibrator adjustments (Cal-Storage board).
e. Connect the precision DC voltmeter between the
0.4 V Calibrator pin-jack and pin-jack ground.
f. CHECK — Meter reading; 0.4 volt ±0.004 volt (with­
in 0.008 volt if this measurement is made outside the
+15~C to +35°C range).
g. Connect the precision DC voltmeter between the
40 mV Calibrator pin-jack and pin-jack ground.
h. CHECK-Meter reading; 40 millivolt ±0.4 millivolt
(within 0.8 millivolt if this measurement is made outside
the +15°C to +35°C range).
i. Disconnect the precision DC voltmeter.
31. Check Calibrator Repetition Rate
a. Change jumper P1066 (see Fig. 2-8) to the AC
position.
b. Install the 7A15A in the left vertical compartment
and the 7B53A in the horizontal compartment.
c. Set the 7A15A for a deflection factor of one
volt/division.
d. Set the 7B53A for auto, internal triggering at a sweep
rate of 0.2 millisecond/division.
e. Connect the 4 V calibrator pin-jack to the input of
the 7A15A with the BNC to pin jack cable.
f. Position the start of the square wave to the left line of
the graticule.
g. CHECK — CRT display for length of one complete
cycle between 4.2 and 6.3 divisions (one kilohertz ±20%).
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