Power Supply, Analysis of Output Circuits

dropping resistors. The fluctuating dc

pull through K703 signal coil, which re-

voltage is smoothed by a choke-input filter

c e i v e s energizing power from rectifiers

network consisting of L722A, C734A,

V704 and V705, and the pull of the springs.

L722B, and C73413. The +150-volt filtered

I f the current through the signal coil is

output is connected to terminal 2 of main

kept constant at a nominal value, the mag-

u n i t receptacle J701 as plate and screen

n e t i c pull will increase in a linear man-

v o l t a g e for all tubes in the tuning unit

n e r as the armature moves to close more

except the oscillator stage in the rf tuner.

and more fingers. The armature is in

mechanical equilibrium only when the

Resistor R785 serves as an additional

c u r r e n t flowing through signal coil K703

voltage-dropping resistor to develop a

+ 1 0 5 - v o l t output, which is controlled by

i s at its nominal B+ value. For all other

v o l t a g e regulator V708. This output is

v a l u e s of signal coil current, equilibrium

c o n n e c t e d to terminal 3 of J701 as plate

i s upset and the armature moves to open

voltage for the oscillator tubes in the

or close the contact fingers. Resistors

tuning unit.

R764 through R769 and R771 through R774

are connected into the control circuit path

b. - 150- Volt D C Power Circuit. T h e

from one side of interlock switch S711 to

full output (terminals 3 and 5) of T702 sec-

t e r m i n a l 1 of T702 primary winding.

ondary winding (a above) is also connected

T h e r e f o r e , the function of the vibrating-

to the cathodes of the dual full-wave recti-

type regulator is to control the amount of

fier CR706. The negative output is filtered

r e s i s t a n c e in the ac input power line cir-

by resistors R786 and R787 and capacitors

cuit. The B+ adjust control (R789) is used

C735 and C746. Resistor R788 is the

to set the nominal amount of current

v o l t a g e - d r o p p i n g resistor in series with

t h r o u g h K703 signal coil. Resistor R791

regulator V709, which holds the output at

functions as a current-limiting device and

-150-volts with respect to chassis ground.

i s connected between the output of recti-

This potential is used as grid and cathode

fiers V704-V705 and the B+ adjust control.

v o l t a g e by cathode follower stage V702,

Filter FL706 filters the current in the B+

as energizing voltage for the two relays in

l i n e ; resistor R763 functions as a further

t h e if. step attenuator of the tuning unit,

c u r r e n t - l i m i t i n g device for K703 signal

and as the source of bias voltage for the

coil.

if.. amplifiers in the tuning unit.

c. +6- Volt DC Power Circuit. C r y s t a l

15. Power Supply, Analysis of

rectifier CR707, connected in a half-wave

Output Circuits

c i r c u i t , rectifies the 6.3-volt ac power

(fig. 6)

d e v e l o p e d across terminals 17 and 18 of

T h e power supply develops outputs of

T702. The dc output, filtered by capacitor

+150-volts, +105-volts, +6-volts, and

C 7 3 7 , is connected to calibration switch

-150-volts with respect to chassis ground.

S706, and is used to energize either

T w o additional outputs, each of 1.2-volts

coaxial relay K701 or K702, depending on

dc, are produced. A 5.8-volt ac and a 6.3-

the switch position.

v o l t ac output is developed for electron

d. 1.2- Volt DC Power Circuit for Elec-

tube heater power. A final circuit develops

trometer V3. One secondary winding (ter-

300-volts dc for use by the coaxial delay

minals 11, 12, and 13) steps down the ac

line charging circuit of impulse generator

i n p u t voltage to 12.6-volts. Crystal recti-

G701.

fiers CR701 and CR702, connected in

a. +150- Volt and +105 Volt Dc Power

f u l l - w a v e circuit, rectify the secondary

C i r c u i t . One secondary winding (termi-

v o l t a g e . The output is filtered by a pi-

nals 3, 4, and 5) of T702 steps up the in-

s e c t i o n filter, consisting of variable re-

p u t voltage to 450-volts. Rectifier tubes

sistor R776 and capacitors C728 and

V704 and V705, connected in a full-wave

C729. Resistor R776 is used to adjust the

c i r c u i t , rectify the stepped up voltage.

d c output of the rectifiers to 1.2-volts,

Resistors R783 and R784 are voltage-

which is connected to terminals 8 and 10