4. Calibration
The first part of this section covers the preliminary circuit
adjustments used for setting-up # new unit or after major servicing,
and the second part describes the calibration procedure which should
be followed to check the instruments operation before a survey.
Figure 20 shows the location of the controls.
4.4.1
Preliminary Adjustments
1.
B supply - Adjust R-80 to obtain a B plus of 250 volts.
2.
Filter circuit adjustments,
a.
Introduce a 2400 ops signal to the input (pin 6 of J-1).
Capacitors C-6 and C~8 are adjusted to produce maximum
attenuation to the 24,00 cps signal as measured at the
grid of V-1A.
(Set the gain control (R-3) above minimum.
A convenient way of obtaining a 21,00 cps signal is to
connect pins 5 and 6 of J-1 together, and then pressing
the lock-on button. |
be.
Place a 7200 cps signal on the input and adjust R-10
and R-13 until maximum attenuation is reached (measure
at the grid of V-2A).
ce
Introduce a 60 ops signal and adjust R-15 and R-16 to
produce maximum attenuation as measured on the grid of
V=2A-.
3.
Connect the output of a Telepulse Receiving Station to the
Teslepulse Central Station input through a 100 to 1 attenuator.
k.
First Sehmtt trigger (V-3) sensitivity - Adjust the front
panel control (R-3) antil pulses of 10 volts amplitude appear
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