User's Manual

f. Release the PRESS TO TEST P4 switch.
g. For twin-indicator tubes, operate the SCREEN and SUP-
PRESSOR SELECTORS switches to the positions specified in
the second line of the tube test data roll chart.
h. Again depress the PRESS TO TEST P4 switch. If the tube
is good, the indicator now should be open, or, in the case of twin-
indicator tubes, indicator No. 1 should be open and indicator No. 2
should be closed.
i. Perform an emission test on the triode of electron-ray in-
dicators with triode sections, such as 6U5 (par. 23). The control
settings for the emission test are specified in the third entry of
the same tube on the tube test data roll chart (par. 12).
28. Ballast Tube Test
Test ballast tubes as follows:
a. Perform the operations indicated in paragraph 15.
b. Operate the FIL-SELECTORS switch to the position speci-
fied in the tube test data roll chart for the tube under test. All
other switches and controls should be in their safety positions
(par. 15d).
c. Insert the ballast tube into the appropriate socket.
d. Turn the ON-OFF power switch to the ON position.
e. Turn the SHORT TEST switch to the V position.
f. Depress and hold down the PRESS TO TEST P1 switch.
Operate the FIL+ SELECTORS switch to each of the positions
specified in the tube test data roll chart. The FIL.-CONT.
SHORT lamp should glow in every position noted. If it does not,
discard the ballast tube.
g. Repeat the procedures indicated in b through f above for
each listing of the tube.
29. Indicator Lamp Test
To check an indicator lamp or other lamps with miniature
bayonet or screw-type bases, proceed as follows:
a. OPERATE THE FIL- SELECTORS switch to position 2.
b. Operate the FIL+ SELECTORS switch to position 7.
c. Operate the FILAMENT RANGE switch to the correct
voltage for the lamp under test. This voltage usually is marked
on the lamp base.
d. Operate the ON-OFF power switch to the ON position.
e. Adjust the FILAMENT fine control until the FILAMENT
VOLTS meter indicates the exact voltage specified for the lamp.
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