Mechanical Adjustments - Sony TC-KB920S Service Manual

PRECAUTION
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback/erase head
rubber belts
idler
2. Demagnetize the record/playback head with a head demagne-
tizer.
(Head demagnetizer do not approach for the erase head.)
3. Do not use a magnetized screwdriver for the adjustment.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
• Torque Measurement
Mode Torque Meter
Forward CQ-102C
Forward
back CQ-102C
tension
FF/REW CQ-201B
Record/Playback Head Height/Declination Adjustment
Procedures:
1. Test cassette: CQ-009C
2. Insert the mirror cassette and put the unit in record/Playback
mode.
1) Height Adjustment:
Check to see if the tape is curling at the tape guide of the head.
If it is curling, tighten screws A, B and C, respectively by
the same angle, moving the head so that it remains at the same
angle throughout the procedure. If it curls on the bottom side
of the mirror cassette (actually the inner side), tighten all the
screws equally; but loosen them if the tape begins to curl on
the top side. (outer side.)
inside outside
Normal Curling on the inner
(Record/playback head side
Tighten screws A , B
as seen from the side of
and C .
the erasehead.)
SECTION 3

MECHANICAL ADJUSTMENTS

pinch roller
capstan
Meter Reading
30 to 65 g•cm
(0.42 to 0.90 oz•inch)
1 to 6 g•cm
(0.014 to 0.08 oz•inch)
70 to 120 g•cm
(0.98 to 1.66 oz•inch)
Curling on
the outer side
Loosen screws A ,
B and C .
– 9 –
2) Declination Adjustment:
While in the record/playback position, set the back tension to
0 (wind the supply reel with something thin like a pencil in a
counterclockwise direction) and make sure there is no curling
or shifting (shifting up/shifting down) at the guide of the
record/playback head.
Because shifting can only occur due to a difference in the width
of the tape and that of the tape guides (curling will otherwise
occur), it is necessary to pay close attention since it can be
easily overlooked.
When there is a shift, tighten screws B and C equally and
change the declination of the head. If the tape is shifting up,
tighten the screws, and if it is shifting down, loosen them.
Repeat the adjustments in steps 1) to 2) and fine adjust the
height and the declination.
Adjustment Location: – record/playback head –
A
B C