Figure 216. Pen-lifter circuit, simplified schematic diagram.

11-6660-204-25

Figure 216. Pen-lifter circuit, simplified schematic diagram.

c. Pen-lifter solenoid L501, when not energized,

ating voltages for the circuits in the radiosonde

recorder.

is actuated by a spring to hold the recorder pen

off the chart. When energized, through the nor-

a. Power transformer T401 is designed to oper-

mally closed contacts of relay K401, it keeps the

ate from 105 to 125 volts at 50 to 65 CPS, with

recorder pen against the chart. When a signal is

the capability of applying the following voltages

received, the dc voltage developed across resistor

from its secondaries:

R420 overcomes the --30-volt bias. Tube V407B

(1) A voltage of 435 volts on each side of the

then conducts and operates relay K401 which, in

center tap (terminals 3, 5, and 7) to supply the

turn, removes the 115 volts ac from pen-lifting

plate voltage to positive supply rectifier tube

solenoid L501. This permits the spring to pull the

V401. Also 115 volts center tapped (terminals 4,

recorder pen to its up position, so the recorder

5, and 6 of that same secondary) are used to sup-

chart is not marked while the balancing motor is

ply excitation to the vibrator inverter coil through

moving the slide-wire to its balance point. When

capacitor C317. Terminal 6 also supplies a 57-volt

switch S201 on the control panel is in the STAND

test signal for S202 on the control panel.

BY position, 115 volts ac is removed from the pen

solenoid, and the pen rests in its up position until

(3) A voltage of 320 volts on each side of the

center tap of the transformer terminals 8, 9, and

the switch is returned to POWER ON.

10 supply the plate voltage to negative supply rec-

tifier tube V408.

2-17. Power Supply

(3) Two 5-volt windings (terminals 11 and

(figs. 2-17 and 2-18)

12; 13 and 14) form the filaments of positive sup-

ply V401 and negative supply V408 rectifier tubes,

The power supply consists of one positive regu-

lated supply, one negative regulated supply, and

respectively. Terminal 13 of the transformer also

has the unfiltered ripple voltage of the 175-volt

one unregulated supply, obtained from a single

negative supply which is applied direct to the 120

power transformer. The power supply furnishes

CPS terminal of switch S202 on the control panel.

filament voltages for all the tubes and all de oper-

2-19