Tektronix Type 130, Инструкция по эксплуатации

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AA
5-1
Ordinarily you will not need to calibrate this instrument
except after tube replacement, and then the calibration
required will be less extensive than the calibration proce-
dure which follows. If in doubt as to the effect of an ad-
justment you wish to make we suggest that you run
through the complete calibration procedure.
Equipment Required
The following equipment is necessary for a complete cali-
bration of the Type 130 L-C Meter:
(1.) Tektronix Type S-30 Delta Standards and connectors.
(2.) DC voltmeter.
(3.) Either an accurate frequency meter, such as a Type
LM-13 or Type BC-221, or a local broadcasting station
with an exact harmonic of 140 kc.
(4.) Low-Capacitance Calibration tools: See Figure 5.1.
Fig. 5.1. Suggested Calibration Tools.
Adjustment Procedure
Remove side panels of L-C Meter. Zero adjust meter with
screwdriver. Check power supply at check point (see Fig-
ure 5-3) for +150 volts ±5 volts. There is a 21 ma load plus
14 ma shunted through the regulator V402.
1. Fixed-Oscillator Frequency, T30 slug
The fixed oscillator should be set to a frequency of 140
kc ±½ kc by one of the following methods:
(a.) Measure the frequency by comparing a Type BC-
221 or a Type LM-13 with the signal from the fixed oscil-
lator at the FIXED OSCILLATOR CHECK POINT (R47), as
shown in Fig. 5-3. Frequency adjustment is made with the
slug in the top of the inductor T30 (see Figure 5-4).
Fig. 5.2. Equipment needed for calibration of Type 130 L-C Meter.
(b.) An accurate source of 140-kc signal is con-
nected to the UNKNOWN jack. The peak-to-peak value of
the signal should be at least one-half volt. The internal
impedance of the source should range between 100 ohm
and 1000 ohm. Turn the RANGE SELECTOR switch to 300
μμ
f and note the deflection on the front panel meter. Ad-
just the slug on T30 until the deflection is zero. For more
precise adjustment, turn the RANGE SELECTOR switch to
10
μμ
f or to the 3
μμ
f position and zero the meter deflec -
tion using T30.
(c.) If a local broadcast station has a harmonic of 140 kc,
the fixed oscillator may be set to zero beat with a station
frequency for the correct harmonic. For example, the fixed
oscillator can be adjusted by checking the fifth harmonic
against a station having a frequency of 700 kc.
2. Variable-Oscillator Frequency
Set the COARSE ZERO control about 10 degrees above
right horizontal, and the FINE ZERO control at full capaci-
tance index horizontal to the right. Set the internal screw-
driver control, C2 (see Figure 503), at mid range, slot vertical.
C2 is mounted on the FINE ZERO capacitor.
Set the variable oscillator also to 140 kc by adjusting the
tuning slug in T1 (Figure 5-4). The variable
–oscillator
signal appears at the GUARD VOLTAGE terminal, and the
VARIABLE OSCILLATOR CHECK POINT (C17), Fig. 5-3.