TM 55-4920-402-13&P
(12) Replace cover and disconnect equipment.
4-14. Tester Test. This test will determine operational
capability of the Tester. Perform performance checks
4-14a thru h only when directed by the
troubleshooting procedure Table 4-17 or when ap-
plicable.
NOTE
Use of the Tester requires a facility il-
luminated by 50 or 60 Hz fluorescent lights
to verify that the Tester is rotating at the
exact speed required. These instructions
assume 60 Hz power for the lights. Step e
explains the differences when using 50 Hz
illumination.
CAUTION
Do not correct the Tester to any voltage
other than +28 vdc or it will damage the
unit.
a. Connect Tester to +28 vdc supply.
b. Set MOTOR switch to ON. Verify that motor
turns freely and that no grinding noises are evident.
c. Set CAM RA TE (RPM) switch to 1800/1714.
Verify that black and white outer ring of segments on
rotor disc appear to be stopped when illuminated by
60 Hz fluorescent room lights. If segments are not
stopped, adjust 1800 rpm adjustment until outer ring
of black and white segments appear to be stopped.
d. Set CAM RA TE (RPM) switch to 900. Verify that
second ring of black and white segments on rotor disc
appear to be stopped. If segments-are not stopped, ad-
just 900 rpm adjustment until second ring of black and
white segments appear to be stopped.
e. Adjustment with 50 Hz power source for the
fluorescent lights is the same as for 60 Hz with the
following exception: The Tester rotor disc speed is ad-
justed using the two inner rings of black and white
segments. Verify that third ring from outside appears
stopped when rotor disc is turning at 1714 rpm. Verify
that inner ring (fourth from outside) appears stopped
when strobe disc is turning at 923 rpm.
f. Set MOTOR switch to OFF.
g. Remove two screws and remove rotor disc. Use a
precision micrometer caliper to measure difference bet-
ween major and minor diameters of cam (Fig. 4-13).
Verify that difference is between 0.0166 and 0.0174
inch.
h. Install Magnetic Pickup. Verify that rotor disc
screws (7, Fig. C-7) pass easily over the top of the
Magnetic Pickup with no binding or sticking.
4-10.6
Change 4
