Eico 667 - MAINTENANCE (Continued); Calibration, Cleaning, and Fuse Replacement; Roll Chart Mechanism Description

6
67
TUBE
TESTER
"
lE/CO^
'<
PAGE
13
and
insert
the
line plug
into a
105-130
volts
AC,
60
cps
line
outlet.
With
no
tube
or
transistor
inserted
in
the
test socket,
and
the
TRANSISTOR
TEST
selector
set
at
"TUBE",
rotate
the
LINE
ADJ. control
R1 until the
voltmeter
reads
130
volts
AC. d)
Depress
push-switch
"C”
so
that it latches,
and
hold
the
metal
clip on
the
cap
lead
against
the
panel
so
that it
makes
good
electrical
contact.
Adjust
the
internal
LEAK
CAL.
control,
R7, for
full-scale
deflection
on
the meter
(zero
ohms on the
leakage
scale), e)
Release
the
"C”
push-switch
by depressing
the
RESET
push-button.
Now
depress
the
LINE
push-switch
and
hold
it
down
(this
switch
does
not latch) while
adjusting
the
LINE CAL.
control,
R18, for
half-scale
deflection
(the
short verti-
cal
"Line
Adjust" on the
meter
scale).
This
completes
the
calibration
of the
instrument.
NOTE:
The LEAK
CAL.
control,
R7, is
located
on
the
underside
of
the
chassis
near
the
FILAMENT
selector
switch.
The
LINE
CAL. control,
R18, is
also
on
the under-
side
of the
chassigvtj'near
the
LINE
ADJ. control.
i?--
CLEANING
TUBE
& TRAiptSTOR
SOCKET
TERMINALS:
After
along
period
of
time, afilm
of
dirt
may form on
the
ietSIde contact
surfaces
of the socket
terminals
which
will
prevent
good
contact
with the inserted
tube and
transistor
pins
or
leads. Spray
or
pour
a little
contact
cleaner
through
the socket
terminals,
if
this
condition
occurs,
to remove
the dirt
film
andrestore
good
contact surfaces.
FUSE
REPLACEMENT:
A
fuse in
series with
the
primary winding
of the
power
transformer
protects
the
tube tester
against damage
due
to overloading.
Do
not
replace
a blown
fuse until
you have located
and
corrected
the
cause
of the failure,
which
can
be
any
one of
the
following:
a) incorrectly
set
controls;
b)
voltage
applied
to shorted
elements;
c) a
short
developed
with-
in the
circuit of the
tube tester.
In the last
case,
it will
be necessary
to
use the
schematic
diagram
to
locate
andremedythe
source
of trouble.
Note
that the
fuse is
a type
3AG 1
ampere
and
thatis
mounted
in a fuse clip
on the
side
of the bracket
supporting the
power
transformer.
Do
notuse
a
higher ampere rating
fuse
type
for replacement.
ROLL
CHART
MECHANISM:
a) Springs: A
small
spring
inside
the
roll
chart
mounting
bracket
provides
a small tension
against
the bottom
of one
gear wheel
to hold
the
rollchartin
any
posi-
tion
to which
it
is set.
Excessive
tension
will
impede
fast
rotation
of
the wheels
when
seeking
tube information,
and
insufficient
tension
will
result
in
a tendency
of
the
roll
chart
to
move
from
the
set
position.
If
necessary,
reset
the
spring
to
provide
the
slight
tension
against
the
wheel
required
for
satisfactory
operation,
b) Center
shaft
clips:
There
are
speed-nut
clips
on
either
end
of
both
center
shafts that
press
against the
outer
wheel
surfaces
and
hold
the
tube-and-wheels
assemblies
together.
If
these
clips
slip
out of
the
shaft,
the
assemblies
will
become
loose.
Should
this
occur,
it
will
be necessary
to
unscrew
the
bracket
from
the
panel
and
remove
the
roller
assemblies.
Then
press
the
clips
against
the
outer
wheel
faces.
AVAILABILITY
OF NEW
TUBE
&
TRANSISTOR
TEST
DATA
ROLL
CHARTS
AND
SUPPLEMENTS
As
new
tube
and
transistor
types
are
released,
an
adequate
number
of
samples
of
each
type are
carefully
tested
and rated
in
the
EICO
laboratories
to
establish
the
correct
control
settings
for
testing
with
the
Model
667.
Periodically,
new
roll
charts
will
be made
available
that
include
these
new
settings.
With
each new
roll
chart,
a
cumulative
supplement
of testing
information
on
obsolete
and
rarely
used
types will
also
be supplied.
When
necessary,
interim
supplements
of new
testing
information
may
also
be made
available.