tube contains excessive gas. When testing a multisection tube,
make the gas test on an amplifier section; it does not apply to diode
sections or to rectifiers.
b. Operate the FUNCTION switch to the TEST position.
c. O p e r a t e t h e P L A T E - S C R E E N R A N G E s w i t c h t o t h e p o s i -
t i o n specified on the tube test data roll chart.
W a r n i n g : Do not touch the top cap of a tube under test after
plate voltage has been applied.
d. Adjust the PLATE and SCREEN fine controls until the
PLATE and SCREEN VOLTS meters indicate the exact voltages
specified on the tube test data roll chart. Red calibration marks
o n the scales of both meters facilitate this adjustment.
e. O p e r a t e t h e B I A S R A N G E s w i t c h t o t h e v o l t a g e o r p o s i t i o n
s p e c i f i e d on the tube test data roll chart.
f. A d j u s t t h e B I A S f i n e c o n t r o l u n t i l t h e G R I D B I A S V O L T S
meter indicates the specified voltage.
g. S e t t h e q u a l i t y S H U N T c o n t r o l t o t h e n u m b e r g i v e n o n t h e
tube test data roll chart, and adjust the PERCENT QUALITY
meter to zero (par. 17).
h. O p e r a t e t h e G M - S I G N A L R A N G E s w i t c h t o t h e p o s i t i o n
specified for the quality test.
i. A d j u s t t h e S I G N A L - V . R . f i n e c o n t r o l u n t i l t h e p o i n t e r o f
t h e SIGNAL VOLTS meter is on the red line.
j. D e p r e s s t h e P R E S S T O T E S T P 4 s w i t c h t o i t s l o c k i n g p o s i -
tion.
k. D e p r e s s a n d h o l d d o w n t h e P R E S S T O T E S T P 6 s w i t c h .
Depressing the P6 switch may cause the PERCENT QUALITY
meter pointer to move upward or downward on the scale. If the
p o i n t e r moves more than three scale divisions in either direction,
the tube contains too much gas for satisfactory operation.
Note. Some tubes develop gas after they have been in operation for a
period of time. When this is suspected to be the case, let the tube remain
under test with operating potentials applied for several minutes before
making the gas test.
l. 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
OFF position, remove the tube under test from the test socket,
and return all switches and controls to their safety positions
(par. 15d).
U s e the following procedure to test the emission (EM) of recti-
f i e r tubes, diode detectors, and multielement tubes.
