LG LH-CX640 Series Service Manual page 117

Adjustment
Procedure
1)
Travel
the
tape
and
check the
bottom
surface
of
the
tape
travels
along
with
the
guide line
of
the
lower
drum.
2)
If
the
tape
travels
toward the
lower
part
of
guide line
on
the
lower
drum,
turn
the
guide
roller
height
adjusting
screw
to
the
left
3)
If it
travels
to
the
upper
part,
turn it
to
the right.
4)
Adjust
the
height
of
the
guide
roller
to
ensure
that
the
tape is guided on the guide
line
of
the
lower
drum
at
the
inlet/outlet of
the
drum.
(Fig.
C-4-1)
DECK
MECHANISM
ADJUSTMENT
4-15
Fig. C -4-1
GUIDE
ROLLER
HEIGHT
ADJUSTMENT
SCREW
ADJUSTMENT
DIAGRAM
Purpose
of
adjustment
: To
ensure
that
the
bottom
surfaceof
the
tape
can
travel
along
with
the
tape
lead
line of
the
lower
drum
by
constantly
and
adjusting
and
maintaining
the
height of
the
tape.
4.
Guide
Roller
Height
Adjustment
Fixtures
and
tools
used
VCR
(VCP)
status
Adjustment
position
\342\200\242
Post
Height
Adjusting
Driver
\342\200\242
Play
or
Review
Mode
\342\200\242
The
guide
roller
height adjusting
screw
on the
supplyguide
roller
and
the
take-up
guide
roller
4-1.
Prior
Adjustment
1)
Play
the
standard
test
tape
after
connecting
the
probe
of
oscilloscope to
the
RF
envelope
output
point
and
the
head
switching
output
point.
2)
Tracking
control
(playback) : Locate
it
at
the
center
(Set the
RF
output
to
the
maximum
value
via
the
track-
ing
control
when
such
adjustment
is
completed
after
the
drum
assembly
is
replaced.)
3)
Height
adjusting
screw:
Flatten
the RF
waveform.
(Fig.
C-4-2)
4)
Move
the
tracking
control
(playback)
to
the
right/left.
(Fig.
C-4-3)
5)
Check the
start
and
the
end
of
the
RF
output
reduction
width
are
constant.
CAUTIONS
There
must
exist
no
crumpling
and
folding
of
the
tape
due
to
excess
adjustment
or
insufficient
adjustment.
Fig.
C-4-2
Fig.
C-4-2
P2 POST
ADJUSTMENT
P3
POST
ADJUSTMENT
CH-1 CH-2
RF
ENVELOPE OUTPUT
POINT
HEAD RF
SWITCHING OUTPUT
POINT
Flatten
the
waveform
by
lightly
turning
the
guide
roller
height
adjust-
ment screw.
When
turning
the
tracking
control
to
both
sides.
OSCILLOSCOPE
When
the
tracking
control
locates at
the center.
Waveform
Connection
Diagram
Fixtures and
tools
used
Measuring
tools
and
connection
position
VCR
(VCP)
status
Adjustment
position
\342\200\242
Oscilloscope
\342\200\242
Standard
test
tape
\342\200\242
Post
height
adjusting
driver
\342\200\242
CH-1:
PB
RF
Envelope
\342\200\242
CH-2:
NTSC
: SW
30Hz
PAL
: SW
25Hz
\342\200\242
Head
switching
output
point
\342\200\242
RF
Envelope
output
point
\342\200\242
Play
the
standard
test
tape.
\342\200\242
Guide
roller
height
adjusting
screw
4-2.
Fine
Adjustment