Lafayette TE-50 - Page 3

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P—(Plate)
This
position
inserts
the
meter
into
the
circuit
during
quality
tests
and
the
indicator
lamp
during
the
“short”
test
of
an
element.
More
than
one
element
should
never
be
placed
in
the “P” position
K—(Cathode)
Switches
not
used
in
the
actual
test
are
left
in
this
position
and
act
as
part
of
the
cathode
or return
circuit.
LEAKAGE-QUALITY SWITCH
This
switch
determines
the
type
of
test
performed
by
the
TE-50.
When
placed
in
the
QUAL
position,
the
quality
or
emission
of
the
tube
under
test
is
indicated
on
the
meter.
The
SPEC
position
applies
a
higher
test
voltage
to
the
tube
and
is
used
only
when
the
letter
(S)
appears
after
an
element
in
the
“P”
column
of
the
chart.
In
the
LEAK
position
inter-element
shorts
and
leakage
are
indicated
by the leakage
indicator
lamp.
LEAKAGE INDICATOR
Used
in
conjunction
with
the
leakage-quality
switch,
it
provides
a
steady
glow
when
an
inter-
element
short
or
leakage
is
present
in
a
tube.
A
“flash”
of
the
indicator
when
switches
are
moved
should
be
disregarded.
This
is
due
to
wiring
and
tube
inter-element
capacity.
METER
The
quality
(emission)
of
the
tube
under
test
is
indicated
on
the
meter.
There
are
three
calibrated
portions
of
the
scale.
1)
The
Replace—?—Good
portion
provides
a
broad
indication
of
quality.
The
green
(good)
section
indicates
sufficient
emission
to
assure
quality
performance,
the
white
(?)
section
denotes
border-
line
emission
and
the
red
(replace)
section
indicates
below-normal
emission.
2)
The
0-100
calibration
provides
a
more
precise
means
of
determining
quality
of
emission
and
may
be
used
to
compare
the
relative
emission
of
similar
tubes.
~,
3)
Tbe
HV
Diodes-OK
calibration
is
for
use
in
testing
diodes
only.
Many
diodes,
cspecially
high
voltage
rectifiers,
have
a
high
internal
resistance,
which
reduces
the
emission
reading.
As
a
result,
tubes
of
this
type
may
produce
an
emission
reading
of
as
low
as
20
and
still
be
per-