Sears SILVERTONE 8070 - Page 8

slide
contact
touches
onlythe
first
two wiper
contacts.
At
all
times during
this step,
switch
cam
(?0)
must
touch switch
cam at
end at switch
slide.
5. Move
pusher
stud
(34)
to the
rRecordt'po-
sition
and
tighten set screw
(33).
6.
Reconnect switch
spring"
Oscillator
Coil
Adjustment-
If
theoscillator
coil
(Ll)
is replaced,
the
setting
of the adjustable
slug should
be checked as
follows:
1"
Connect
a frequencymeter
between
point
2
of
the
erase
head and
ground.
2"
Turn
volume
and
tone
controls
on.
3. Set
the Play-Record
knob
(5)
to the
"Recordrt
position.
4. Adjust the
oscillator
slug
for
a
52.5 KC
reading
on the
meter
(A
non-metallic
screwdriver
should
be used for this
adjustment.)
Hum
B4le4qq-
When either
the 12AX?
tube
or the Head
(39)
has
been changed,
the settinq
of the
hum balancing
con-
trol should
be
checked. This can
be
done as follows:
l.
Connect
an A.C.
V.T.V.M. across
the
speaker
coil. The meter's
lowest
scale should
have
a
.
I
volt reading at full
scale
deflection,
or
at
least
1,/ 3
of full scale.
2.
Turn volume control and
tone control fully
clockwise.
3.
Set control knob
(5)
to the
playback position.
4" Adjustthe
hum
balance controlfor aminimum
reading.
This reading
should not exceed
.1
volt.
LUBRICATION
The lubrication
applied at
the time of
manu-
facture
should
be
sufficient
for
a long
period
of time.
In
cases
of unusual use, high
operating temperatures,
or
the replacement
of
a
part,
lubrication
may
be
required.
TROUBLES
Improper
Tape Take-Up-
l.
Spindle
(48)
binding.
(a)
Lubricate and
check end
play.
See ad-
justment
section
"Spindle
End
Playr'.
2.
Improper
Take-up spring
(83)
action.
(a)
See
"Take-up
Lever Adjustment".
3. Drive
belt slipping.
(a)
Clean
pulleys.
4.
Broken drive
belt.
PAGE
8
Fails To Fast
Forward
Properly-
l.
See above
except for
step 2.
(a)
See
corresponding
remedies
above.
Fails
To
Fast
Rewind Properly-
1.
See above
except for step 2.
(a)
See
corresponding
remedies above.
CAUTION:
When replacing
belt
(59)
be
sure
to
give
it a
half-twist.
Stalling Or Binding-
l.
Speed
control
(11
settingchanged
while
unit
is
not
turned on. This should
be
done
only while motor
(62)
is rotating.
(a)
With motor
(62)
turned
on, try moving
Speed Control
(1)
up and
down several
time6.
(b)
Should the above fail,
try holding
Fast
Forward Control
to the left as
far as it
will
go,
and
with the
other hand manually
rotate
Take-up Reel
Spindle
(48).
(c)
If
binding continues it
will
be
necessary
to remove unit from
cabinet and free any
binding
action.
Speed Does
Not Agree
With
Speed Setting-
l.
Bend Speed Control
Bracket
(?4).
(a)
Straighten
bracket
(?4)
so
that upper and
lower fingers
are
equal
distant
from drive
belt when
belt
is in
normal
operating
position.
2.
Broken
"ears"
on
Drive
Pulley
(61).
(a)
Replace entire
motor
(62).
Tape Creeps Out
Of Tape
Slot-
l. Head
(93)
improperly
adjusted.
(a)
See
"Head
Alignment
AdJustment".
Plays Back But Does
Not
Record-
1.
Bad component.
(a)
Cheek
voltage
and
resistance
readings.
2.
Switch slide not
contacting
proper
terminal.
(a)
See
"Switch
Cam
Adjustment".
Does Not
Completely
Erase Previous
Recording-
1.
Bad 6VBGT
tube.
(a)
Replace
tube.
This tube may function
properly
as a
power
amplifler
but
not as
an oscillator
which
is
needed for
erasing.
2.
Bad Head.
(a)
Replace head following
"Head
Alignment
Adjustment".