Eico 667 - DEVELOPING SETTINGS FOR NEW TUBES (Continued); Diode MERIT Test Procedures; Dual Tube and Rectifier Testing

667
TUBE
TESTER
‘
lE/CO*-,
<
PAGE
19
entering
chart
5 at
the
maximum
allowable
diode
plate
current
and reading
off
the
corresponding
PLATE
control
setting.
The
GRID control
remains
at the
setting
previously
developed
for
thetriode or
pentode
section
(if
any)
in the
same envelope.
(Actually
the
GRID
control
setting
has no
effect
in
this
test provided
that it
is
set
above7;
itisleftat
the
previously
developed
setting
to
avoid
unnecessary
re-setting.
)
The V
lever
is set
first
at position land
the
meter reading
observed
with
the
MERIT
lever
held
down.
Note
that the
voltage
applied
to the
diode
in
this test
is the grid
voltage
selected
by the V lever;
namely
5
volts
at
position
1,
15 volts
atpositions
2
and
3,
and 45
volts
at position
4
(all
in volts
rms,
60
cps). Refer
to
these
voltages
to determine
whether
the
maximum
voltage
that
can
be applied
to the
diode
is
exceeded
at
any V
lever
position.
If
the
meter
reading
at the
V lever
position
1
is
substantially
less
than
100
on
the
0-140
scale,
proceed
to positions
2
and
4
succes-
sively (position
3
is identical
to
2
as
regards
grid
voltage)
if need
be,
observing
the
limitation
of maximum
allowable
applied
voltage.
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
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.
n) The
foregoing
applies
only
to
single
triodes,
pentodes,
light-duty
diodes
included
in the
same envelope
with a triode
or
pentode,
and
half-wave
rectifiers.
For dual
triodes
or
triode-pentodes,
both sections
of the
tubes
should
have
the
correct
opera-
ting
voltages
applies
simultaneously.
For a
triode-pentode,
connect
the
triode
plate
lever
to
position
3,
the pentode
plate
lever
to
position
4,
and
the
pentode
screen
lever
to
position
3;
both control
grid
levers
may
be
set at position
5.
Refer
to the roll
chart settings
for the
6U8
and
12AU7 for
this type
of
operation.
In
the
case of
full-wave
rectifiers,
only
the section under
test
has the
operating
voltage
applied.
Refer
to
the roll
chart settings
for
the5U4as
atypical
full-wave
rectifier.