Section V. ADJUSTMENTS, REPAIRS, REPLACEMENT, AND TESTING

TM 11-6660-204-25

ation, return the original tubes to their sockets before

case. Do not substitute tube type 5184A for tube

forwarding the defective item of equipment to a

12AU7 in the tube sockets for V301 and V303, and

higher maintenance level for repair.

do not substitute tube type 5751 for tube 12AX7 in

f. Interchangeability of Tubes. Unless specifically

the tube sockets for V302 and V310; such substitu-

tions could disable the set completely. The preferred

permitted by published instructions, different ver-

sions of the same tube type (ruggedized, nonrugge-

type tube 5R4GWA may be substituted for the ear-

dized, etc.) should not be substituted for the desig-

lier type tube 5R4GWY in the tube sockets for recti-

nated

type.

Signal

Data

Converter

f i e r s V401 and V408 in Power Supply

CV-146A/TMQ-5 uses several ruggedized tubes

PP-968-TMQ-5.

which should be replaced with the same type in each

Section V. ADJUSTMENTS, REPAIRS, REPLACEMENT, AND TESTING

by loosening the locknut and turning the setscrew on

3-25. Chart Feed Adjustments

the drive cable guide pulley until the spring is fully

a. If the chart does not feed out straight during

compressed. Back off one full turn of the adjusting

operation of the recorder the cause is probably mis-

screw and tighten the locknut.

alignment of the chart supply roll. The left edge of

the chart should be against the guide collar mounted

3-27. Adjustment of Split Gear Bias

on the intermediate guide rod, and the perforations

The split gear bias adjustment is performed to elimi

on the edge of the chart should coincide with the

nate gear backlash. The need for this adjustment is

extruded teeth around the left end of the chart roller.

usually indicated by gear chatter, excessive error in

If the two positions do not align, loosen the two

hysteresis, or linearity calibration test errors.

locknuts on the left side of the chart supply roll shaft,

a. Remove the nut below the pinion gear and pull

one on each side of the recorder casting (fig. 3-2).

the pinion gear from the motor shaft (fig. 2-19).

Shift the chart roll so that the chart will just rub

b. Expand the springs of the split gear by displac

against the guide collar and the perforations on the

ing the two halves of the gear by three teeth.

chart fit over the roller teeth. Tighten the locknuts.

c. While holding the split gears in place, replace

The fiction brake on the chart roll shaft should be

the pinion gear. Replace the nut on the motor shaft.

only tight enough to prevent the chart from dropping

below the bottom of the recorder. Excessive brake

NOTE

action may cause the chart to creep sidewise as it

If the nut securing the split gears is too

advances.

tight, the gears cannot move indepen-

b. If the chart on the recorder feeds out intermit-

dently, resulting in a split gear bias of

tently there is too much dragon the supply roll which

zero. A clearance of approximately

is caused by friction clutch slipping at times or there

1/32-inch should be provided between the

is a possibility of not enough clutch pressure. Check

nut and the gears.

with the manual chart advance knob (fig. 2-20) for

3-28. Recorder Pen Adjustment

ease of operation. If there are no signs of mechanical

binding, increase the clutch friction by tightening

a. Mechanical Pen Lift Adjustment. If the pen

the set nut and locknut located on the right side of

does not lift 1/16 inch from the chart as it moves

the chart roller shaft (fig. 2-19 or 3-2) until the

across the scale, check the position of the double-

proper chart advance rate is obtained. Another possi-

ended bolt connecting the solenoid plunger link to

ble source of trouble is a loose pinion gear on the

the pen-lifter bracket. To obtain the proper distance,

motor shaft, which may be easily tightened by the

throw the power switch to POWER OFF. Loosen the

setscrew in the gear hub.

locknut (fig. 2-21) and turn the double-ended bolt

c. If the lubricating instructions given in para-

until the pen is 1/ 16 inch from the chart. Tighten the

locknut. If the pen carriage shaft rotates sufficiently

graph 3-3 have not been followed, wear or binding

may occur between the ratchet wheel hubs and shaft

but the pen does not rise, tighten the two screws in

(figs. 3-1 and 3-2). Apply oil only as needed to cor-

the pen clamp mounted on top of the pen carriage be

rect the trouble, then lubricate as directed in para-

sure to allow free movement of the carriage.

graph 3-3.

b. Pen Point Pressure Adjustment. If the pen does

not mark the chart, check the condition of the pen for

3-26. Drive Cable Tension Adjustment

an adequate ink supply. If these are satisfactory, but

the pen still makes either no mark or a very light one,

The tension on the drive cable should be between 1

check the pressure of the penpoint against the paper.

and 1.25 pounds. This amount of tension is obtained

3-21

Change 3