Figure 8. Line voltage sensing circuit, schematic diagram.
audio amplifier
diode CR7901 is also applied through ter-
(c) In Positions 7, 9, 13, and 14
Con-
minal B of connectors J7907 and P7801 to
nections are made through ter-
the line voltage sensing circuit consisting
minal H of connectors J7906 and
of resistors R7817, R7818, and R7819,
P7601 to supply power to the
rheostat R8716, capacitor C7802, unijunc-
11.5-mc amplifier and through
t i o n transistor Q7806, and dc switch
terminal C of connectors J7905
CR7803. The operation of this circuit is
and P7401 to diode CR7402 .
explained in paragraph 11.
(d) In positions 12, 15, 16, and 17.
c. If tie power source voltage is above
its minimum limit of +22 volts dc, +16
Connections are made through
volts dc is applied through terminal A of
terminal L of connectors J7904
and P7701 to the 5.65-mc ampli-
connectors P7801 and J7907 to the follow-
fier and through terminal A of
ing places:
(1) Terminal F of connectors J7907
connectors J7905 and P7401 to
and P7801 to supply power for the
diode CR7403.
Schmitt trigger circuit.
(e) In position 18. Connections are
(2) Terminal K of connectors J7907
made through terminal D of con-
and P7801 to supply power to the
nectors J7904 and P7701 to the
voltage supply limits sensing cir-
47.0-mc amplifier and through
cuit.
terminal D of connectors J7905
(3) One side of RED indicator lamp
and P7401 to diode CR7401.
DS7901 and GREEN indicator lamp
d. When +16 volts dc is applied to diode
DS7902. The other sides of the
CR7401, CR7402, or CR7403, it is fed
lamps are connected through ter-
through terminal B of connectors P7401
m i n a l s E and D of connectors
and J7905 and through terminal K of
J7907 and P7801 to the collectors
connectors J7903 and P7501. The voltage
of transistors Q7804 and Q7805,
is applied through inductor L7501, through
respectively, in the Schmitt trigger
terminal F of connectors P7501 and J7903,
circuit.
through inductor L7302 and across filter
(4) Switch S7902E.
capacitor C7302 to supply power to the test
(a) In positions A, 2, and 8. No con-
probe rf preamplifier.
nections are made.
13. Selector Switch Position A
(b) In positions 3,4,5,6, 10, and 11.
A connection is made through
(A, fig. 9)
When the selector switch is in position
terminal H of connectors J7905
A, either a +16-volt dc point on the unit
and P7401 to supply power to the
11
