Adjustment of Automatic Time-Print Switch

TM 11-6660-204-25

record at 95. Let the recorder trace a 1/4-inch line to

the setting of the OUTPUT LEVEL control during

insure proper setting of the control.

the following procedures.

b. Linearity Calibration Test.

3-37. Adjustment of Automatic Time-Print

(1) Set the frequency standard CYCLES control

Switch

to 190. Adjust the radiosonde recorder REF. AD-

JUST control as necessary to cause the recorder to

When Radiosonde Recorder AN/TMQ-5A, -513, or

print at 95 recorder divisions. Allow sufficient time

-5C are used with Rawin Set AN/GMD-1(*), the

for the recorder to print a trace approximately

action of automatic time-print switch S504 (fig. 3- 14)

3/8-inch in length. (Do not make any additional

should cause the control recorder to produce a time

changes in the REF. ADJUST setting for the remain-

print each time the radiosonde recorder penis moved

der of this test).

up-scale through the range of 89-91 recorder divi-

(2) Change the output of the frequency standard

sions. If automatic time printing occurs when the

to 180 hertz (cycles). Again allow the recorder to

recorder pen is at any other position, perform the

produce a 3/8-inch trace.

following adjustment procedures: (The automatic

time-print switch is not included in earlier models of

(3) Using all frequencies (including zero) availa-

ble from the frequency standard, repeat step (2) in

the radiosonde recorder.)

descending order and then in ascending order.

a. Turn the recorder power switch to the OFF posi-

(4) Place the frequency standard POWER

tion.

switch to OFF. Place the recorder POWER switch to

b. Manually turn the balancing motor split-gear

OFF or STANDBY as desired.

assembly to position the pointer at the 90-division

c. Construction of Linearity Correction Graph.

chart line on the scale.

(1) Use the manual chart advance knob to ad-

c. Loosen the locking screw securing the bracket

vance the portion of the chart containing the record-

on which the time print only microswitch (S504) is

ings and tear off the chart approximately 8-inches

mounted.

after the last trace. Place this portion of the chart on

d. Move the bracket to a position that just causes

a smooth, flat surface in preparation for determining

microswitch S504 to close. This can be determined by

the deviation from linearity and for plotting the cor-

an audible click when the switch closes.

rection graph.

e. Tighten the adjustment screw and replace the

(2) Using a straight edge and a sharp pencil,

frequency-time recorder in the cabinet.

draw a straight line vertically connecting the two

f. Recheck the action of S504.

traces obtained for each frequency value. Use the

3-38. Linearity Calibration

center of the width of the traces as starting and

terminating points.

The printed record of the radiosonde recorder should

(3) Draw a baseline horizontally across the chart

have a nearly linear relation to the input frequency.

through the midpoints of the lines constructed in (2)

Any deviation from the linearity should be plotted as

above.

a linearity correction graph to be used for corrections

(4) Determine the recorder division where the

of recorded meterological data.

190 hertz line crosses the baseline. The deviation

a. Preliminary Procedures.

from linearity is the difference between this value

(1) Connect the special purpose cable (split ca-

and 90. The deviation is plus if this value is greater

ble to J101 on the radiosonde recorder. Connect the

than 90, and is minus if it is less than 90 (fig. 3-16).

spade lugs of the cable to the matching color-coded

(5) Repeat step (4) for all other recorded frequen-

terminals of Frequency Standard TS-65(*)/FMQ-1.

cies (90, 70, 60, 50, 40, 30, 20, 10, and 5 recorder

Connect the recorder and the frequency standard to a

division). The maximum allowable deviation is 0.3

source of ac power and place their POWER switches

chart divisions. Should the deviation exceed this tol-

to ON. Allow a warmup time of 10 minutes.

erance, corrective maintenance should be performed

(2) Adjust the sensitivity (para 3-34a).

and a new linearity calibration test is performed.

(3) Rotate the SIGNAL SELECTOR switch to

(6) Draw the linearity correction as illustrated in

SC and adjust REC ZERO to cause the pen to record

figure 3-17. Note that the corrections have opposite

at the zero chart ordinate.

signs as compared to the deviations.

(4) Rotate the SIGNAL SELECTOR to SIG.

(7) Date and retain the correction for future ref-

Set the OUTPUT LEVEL control of the frequency

erence.

standard to its approximate midpoint. Check to as-

d. Corrective Maintenance. If any deviation ex-

sure that the recorder will properly respond to all

ceeds 0.3 divisions, one or more of the following items

frequency outputs from the TS-65( )/FMQ-1. Read-

may be the cause.

just the OUTPUT LEVEL control as necessary to

(1) Loose pen or pen carriage (fig. 3-9).

provide operation at all frequencies. Do not change

3-25

Change 3