TM 11-5826-225-35
n. Set the test set DC POWER switch to ON,
(2) Connect P1 of the test set to P301 of the con-
and adjust R1 for an indication of 26 2.0 volts on
trol unit to be checked. Keep the control unit outside
the ac meter.
the test set.
(3) Connect the test set to the equipment as
o. Set the test set DC POWER switch to OFF,
shown in figure 2-19.
and tighten the locknut on R1.
(4) Set the function switch on the control unit to
ADF.
3-22. Control Unit Alignment
(5) Set the range switch on the control unit to
NOTE
840-1750.
Refer to figure 5-17 throughout the align-
(6) Rotate the TUNE control until the small cir-
ment of the control unit.
cle between 1,400 and 1,500 kc is bisected by the
a. Vertical Alignment of Dial Drum.
hairline in the frequency window.
(1) Set the range switch to 190-400.
(7) Set the RECEIVER-CONTROL switch on
(2) Loosen two setscrews (78) and rotate collar
the test set to CONTROL.
(77) until the band markings around the top of dial
(8) Set the POWER switch on the test set to ON.
drum (41 ) are clearly visible through the FREQUEN-
(All other switches and controls on the control unit and
CY window on front panel (93). Tighten one of the
the test set may be in any position.)
setscrews (78).
NOTE
(3) Rotate the TUNE knob (97) in either direc-
In (9) below, do not allow spur gear (122) or
tion. If the bottom of the dial drum (41) rubs frame
spur gear (123) to become disengaged with
(136) loosen the one setscrew (78) and readjust collar
spur gear (120). Disengagement will cause
(77) until dial drum (41) no longer rubs frame (136).
loss of spring loading between spur gears
Tighten two setscrews (78).
(122, 123). Refer to paragraph 3-6c to
(4) Set the range switch to 840-1750,
restore spring loading.
(5) Rotate the TUNE knob (97) in either direc-
(9) Loosen two setscrews (127), and use a nar-
tion. The band markings around the bottom of dial
row- bladed screwdriver to rotate the shaft on transmit-
drum (41 ) should be clearly visible through the FRE-
ter synchro (156) until the BEARING INDICATOR
QUENCY window on front panel (93), and the top of
on the test set indicates exactly 239 degrees,
dial drum (41 ) should not rub frame (136). If' neces-
(10) Apply blue varnish to the threads of two
sary, loosen two setscrews (78) to readjust collar (77).
setscrews (127).
(6) Set the range switch to 190-400, and repeat
(11) Tighten two setscrews (127).
(3) above.
(12) To check the accuracy of the transmitter
b. Dial Drum Rotational Limits.
synchro, perform the procedures in (a) and (b) below.
(1) Set range switch to 850-1750.
(a) Rotate the TUNE control until 1,700 kc is
(2) Rotate the tune control clockwise. Loosen
indicated in the FREQUENCY window. The BEAR-
setscrews (44) and rotate gear (43) until alignment
ING INDICATOR on the test set should indicate 203
mark on dial drum is aligned with hairline on glass fre-
1.0 degrees.
quency window. Tighten setscrews.
(b) Rotate the TUNE control until 850 kc is in-
(3) Loosen two setscrews (71), and rotate the
dicated in the FREQUENCY window, The BEARING
TUNE control to the maximum counterclockwise posi-
INDICATOR on the test set should indicate 343
tion.
1.0 degrees.
(4) Apply blue varnish to the threads of two
(13) Set the POWER switch on the test set to
setscrews (71 ).
OFF.
(5) Tighten two setscrews (71).
(14) Disconnect P1 on the test set from P301 on
c. Alignment of Tuning Synchro.
the control unit.
(1) Remove the control unit contained in the test
(15) Install original control unit in the test set.
set .
Change 5
3-31
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