f. I n s e r t a n d h o l d t h e l a m p i n t h e c e n t e r o f t h e S E V E N s o c k e t .
If the lamp is good, it will light with normal brilliancy.
Caution: Do not test glow lamps with the TV-2(*)/U unless
these lamps are supplied with a current-limiting series resistor.
g. When
the
test is completed,
operate the ON-OFF power
switch to
the
OFF position and
return the FIL- and FIL+
SELECTORS switches, the FILAMENT RANGE switch, and
the FILAMENT fine control to their safety positions (par. 15d).
As an example of a complete tube test, assume a 6SQ7 tube is
to be tested. The 6SQ7 tube is a twin-diode high-mu triode used
as
a
combined
detector,
amplifier,
and
automatic
voltage
control
tube in radio receivers. It has an eight-pin octal base. Rotate
the tube test data roll chart until the 6SQ7 appears in the TUBE
TYPE column in the left-hand window of the tube test data roll
chart housing. In addition to tests for short circuits, interelement
leakage, and filament continuity, note that this tube must be tested
three times: to test the transconductance of the triode section, to
measure the emission of diode No. 1, and to measure the emission
of diode No. 2. In addition, the gas content of the tube must be
checked.
a. Preparation. Adjust the tube test data roll chart so the first
line on which 6SQ7 appears is in the center of the window between
the horizontal red lines. Refer to the column headings marked
on the tube test data roll chart housing and proceed as follows:
(1) Perform the operations described in paragraph 15.
(2) Set the FUNCTION switch to TEST (T).
(3)
Set
the
SELECTORS
switches
to
the
positions
indicated
in the SELECTORS (L TO R) column on the tube test
data roll chart and in the order indicated:
(a) FIL-- to 7.
(b) FIL+ to 8.
(c) G R I D t o 2 .
(d) P L A T E t o 6 .
(e) S C R E E N t o 0 .
(f) C A T H O D E
to
3.
(g) S U P P R E S S O R t o 0 .
( 4 ) Set the FILAMENT RANGE switch to the 6.3 position.
( 5 ) Insert the 6SQ7 tube into the OCTAL test socket.
( 6 ) Set the ON-OFF switch to the ON position and allow a
l-minute warmup.
