3A6GT
3Q4
3B7
3Q5QT
3D6
3S4
3LF4
3V4
d. I f t h e l a m p b u r n s c o n t i n u o u s l y o r g l o w s d u r i n g t a p p i n g i n
a n y one of the five positions of the SHORT TEST switch, the tube
contains short-circuited electrodes. Discard the tube unless an
e x c e p t i o n is noted on the tube test data roll chart.
e. D i s r e g a r d a m o m e n t a r y f l a s h o f t h e F I L . C O N T . S H O R T
indicator lamp while the SHORT TEST switch is being moved
f r o m one position to the next. This flashing usually is caused by
t h e charging of a capacitor in the test circuit.
Note. Some tubes normally test as shorted when the SHORT TEST switch
is in certain positions. Before discarding a tube that shows a short, check
the tube test data roll chart NOTES column for information on normal short
indications.
f. W h e n t h e t e s t i s c o m p l e t e d , s e t t h e O N - O F F s w i t c h t o t h e
O F F position, remove the tube under test from the test socket, and
return all switches and controls to their safety positions (par.
15d) .
Follow the test procedure in a t h r o u g h e below to determine the
interelement leakage (LK) in megohms between electrodes of the
tube under test.
a. P e r f o r m t h e o p e r a t i o n s d e s c r i b e d i n p a r a g r a p h s 1 5 a n d 1 6 .
b. O p e r a t e t h e F U N C T I O N s w i t c h t o t h e L E A K p o s i t i o n . T h i s
p o s i t i o n connects the PLATE meter into the circuit to serve as an
ohmmeter for this test only.
c. S e t t h e o h m m e t e r ( P L A T E m e t e r ) t o z e r o a s f o l l o w s :
( 1 ) Operate the SHORT TEST switch to the V position.
(2) Turn the PLATE fine control to its maximum counter-
c l o c k w i s e position.
( 3 ) Depress the PRESS TO TEST P1 switch.
( 4 ) With the P1 switch held in its depressed position, adjust
t h e PLATE fine control until the pointer of the PLATE
meter indicates zero (250 on center scale) on the ohm-
meter (top) scale.
(5) Release the P1 switch.
d. O p e r a t e t h e S H O R T T E S T s w i t c h s l o w l y f r o m t h e O P E R .
p o s i t i o n to positions V, W, X, Y, and Z; at the same time, watch
for a deflection of the PLATE meter pointer.
