Lafayette TE-50 - Page 5

Set the “ Leakage-Quality ” switch to LEAK
4. Set the FIL. VOLTS switch to the position specified on the tube chart for the tube to be tested.
Set the appropriate elemental slide switches to the “F” and “N” positions (as specified on the
tube
chart).
All
other
elemental
switches
should
be
set
to
the
“K”
position.
6. Insert the tube into its correct socket. Allow at least 30 seconds for it to warm up.
7. With the exception of those previously set to““F” and “N”, move each elemental slide switch
one
at
a
time
to
the
“P”
position.
Tap
the
tube
and
observe
the
LEAK
IND
lamp,
moving
each
switch
to
the
“P”
position
and
then
returning
it
to
“K”.
i
WARNING:
AT
NO
TIME
MUST
THERE
BE
MORE
THAN
ONE
SWITCH
IN
THE
“P”
POSITION.
A
steady
glow
in
the
Leakage
Indicator
lamp
when
any
one
of
the
switches
is
set
to
“P”
indicates
a short.
A
slight
glow
may
be
disregarded
when
testing
certain
audio
tubes
such
as
the
6L6,
50L6,
etc.
These
tubes
have
a
high
inherent
leakage.
This,
however,
does
not
affect
their
normal
operation.
In
all
other
cases,
no
glow
is
desirable,
but
a
slight
glow
may
be
considered
passable.
Note:
A
steady
glow
on
any
of
the
elements
listed
in
the
filament
continuity
column
does
not
indicate
a
“shorted”
tube.
This
indicates
filament
continuity.
8.
Remove
the
tube
from
the
socket.
HOW -TO TEST A TUBE FOR QUALITY
Do not conduct this test until you have checked the tube for shorts and leakage. If you have already
done so and the tube appears normal with respect to shorts or leakage, proceed as indicated below.
Do not change any of the control settings previously made for the tube under test unless instructed
to do so.
1.
Set
the
Leakage-Quality
switch
to
QUAL.
If
the
letter
(S)
appears
after
the
element
listed
in
the