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Mechanical Adjustment and Repairs
a
REC/PB head
1. Turn the adjustment screws ((A)and
screws
If either of the record/play-
(Azimuth
) so that measure ''a" is 3.5mm.
back head and the erase head
inclination)
2. Insert screws
in the spring and
shown low performance be-
unfasten it on the head panel.
cause of wear, broken wire of
3. Fasten the screw(D) on the head
excessive magnetization, it
panel.
should be replaced.
4. Fasten the screw (C).
If necessary, adjust playback
5. Turn the adjustment screw(D)so that
sensitivity, REC bias current,
the head is horizontal.
and bias trap.
6. Playback the test tape C-120 (front
(Screw (A) and(B) are head
cutted cassette) and turn the adjust-
inclination adjustment.
ment screws ().6) and(D) so that
Screw
is head azimuth
the test tape move running to no
adjustment.
touch the tape guide tip (upper or
Screw(C)is fixed.)
under side).
If checking is difficult, cut
1)When the test tape uncorrect touch-
front upper side (near E head,
ing at upper side of tape guide,
REC/PB head and capstan) of
loose the adjustment screws
and
the cassette C-120 by a cutter
to move the head position at
knife, etc, then easy check it.
under side.
2)When the test tape uncorrect touch-
ing at under side of tape guide
fasten the adjustment screws (A)and
(B)to move the head position at
upper side.
7. Insert the cord plug into the LINE
OUT jack (or REC/PB), and connect
the other end of the cord to a
V.T.V.M. (vacuum tube voltmeter}.
8. Play the azimuth adjustment test tape
(e.g. JVC's VTT-653, 10kHz).
9. Turn the azimuth screw
so that
the output will become maximum.
10. If output of left and right channels
unbalance level, turn the adjustment
screws (A) and
for correct the head
Position.
1) If output of right_channel less level
loose the screw
and fasten the
screw(B).
2) If output of left channel less level,
fasten the screw
and loose the
screw(B).
11. After this adjustment, the screw(B)
should be locked with a bond.
head
panel
tape guide
—=—
(upper side)
tape
tape
tape guide
(under side)
<_
After replacement, adjust the
head height position.
Playback the test tape C-120 (front
cutted cassette), and turn the adjust-
ment screw
so that the test tape
move running to no touch the tape
guide tip (up or under side).
1)When the test tape uncorrect touch-
ing, at under side of tape guide, loose
the screw
;
2)When the test tape uncorrect touch-
ing, at under side of tape guide, fasten
screw
( F ) .
Erasing head
(height)
tape guide
~=—(upper
side)
tape
tape
el
tape guide
(under side)
CD-1770/A/B/C/E
No. 4144
— 10 —
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