Eico 667 - TUBE CHARTS (Continued); Chart 5 and Power Rectifier MERIT Settings; Light-Duty Diode MERIT Test Settings

PAGE
18
««««««
L
]E/CO
l
-
1
667
TUBE
TESTER
"PLATE"
CONTROL
SETTING
j)
Obtain
the
GRID
control settings that
give
a reading of
100
on the meter
for
several
other tubes of
the identical type and establish an average setting.
k) Record the
final
settings
of
all
controls
under
the
proper
column headings
on
the
roll chart. The settings so obtained
will
permit you to test other tubes of this type
until information
is
obtained from
EICO
on
a
new roll
chart
or supplement.
Note
that the settings you obtain
may
differ from
the
settings
obtained using standardized
or
"bogie"
tubes.
l)
For a power rectifier,
the
procedure for
obtaining
MERIT test
settings
is
the same
up to step h).
(The
S
lever
and
the PLATE
control
are
set as
usual
to cause a
meter
reading
of
100
on the
0-140
scale when
maximum
allowable
plate
current
is drawn.
)
The
GRID control
is set at zero
to actuate the
switch which
inserts
the 4000
current-
limiting
resistor.
The V
lever
is set
to
position
1
and
the
MERIT lever
held down
while
the meter
is
read.
If
the
reading
is
substantially
below
100,
move
the
V
lever
to
position
2,
providing
the voltage
rating
of the
tube
is
not
exceeded.
If
the
reading
is
still
substantially
below
100
move the
V lever
to
position
3,
again pro-
viding
that
the voltage
rating
of the
tube
is not
exceeded.
If
and
when
you come
to
a position
of the V
lever
for
which the meter
reading
does
appreciably
exceed
100,
return
the V lever
to
the next
lower
position and
adjust
the
PLATE
control
for
a
meter reading
of
100.
If
this
does not
occur even
at V lever
position
3
(the same
plate
voltage
is applied
at position
4),
adjust
the
PLATE
control
for a meter reading
of 100
at this
position;
the
current drawn
will
normally
be sufficient
for
a
good
test.
Completion
of the
procedure
is covered in
steps
j
and k above,
except
that instead
of finding
an average
GRID
control
setting
(step
j),
find
an average
PLATE
control
setting.
m)
For light-duty detecting
diodes,
such
as
are
normally
included
in the
same envelope
with
a triode or pentode,
MERIT test
settings should
be obtained
after developing
the
settings for the triode
or pentode
section. As instructed
earlier,
the
diode
plate
levers are
set to position
6
(which
position
they
retain
for
the
triode
or pentode
test.
It
will therefore
normally not
be
necessary
to reset
levers
1 through
12
& C
when
going
from the triode or
pentode
test to the diode(s)
test(s).
The
S
lever
is
always set
at position
6
and the
preliminary
PLATE
control
setting
determined
by