Sony CFS-903L - Mechanical Adjustments; Electrical Adjustments

SECTION 2
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
FRONT CABINET ASSEMBLY jonaie
HANDLE ASSEMBLY
TUNING KNOB
@ Remove the
two hooks,
handle
TEX hook
Tew
screwdriver
NS
aN
2
ROR
Se
DB BE co) ‘
dial pointer
DIAL POINTER SETTING
Orturn the tuning shaft fully counterclockwise.
Oset the left side of the dial pointer to the scratched
life on the tuning chassis. (Arrow
scratched
line
ao:
= "@
tuning
chassis
@ +BVTP3 x 20
@ +BVTPS x 20 (5 pes.)
@ side panel (right
@ +RKTP3 x8
two portions:
There is the same part
on the opposite side.
@ tuning chassis
)
@ +BVTP3 x 12
assembly
tuning shaft
jae Meat a
SECTION 3
MECHANICAL ADJUSTMENTS
PRECAUTION
Clean the following parts with a denatured-alcohol-
moistened swab:
record/playback head pinch roller
erase head rubber belts
capstan idlers
Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head demagnetizer close
to the erase head.)
Do not use a magnetized screwdriver for the adjustments.
After the adjustments, apply suitable locking compound to
the parts adjusted.
The adjustments should be performed with the rated
power supply voltage unless otherwise noted.
Power supply voltage: 9V dc.
Torque Measurement
Torque meter
Meter reading
30 —75 g-cm
0.42 — 1.04 oz-inch
CQ-102C ( 0z-inch)
FWD 2-6 g-cm
back tension (0.03 — 0.08 oz-inch)
30 ~— 75 g-cm
(0.42 — 1.04 oz-inch)
CQ-102RB -
REV 2-6 g-cm
back tension (0.03 — 0.08 oz:inch)
60 —130g-cm
C08 (0.83 — 1.81 oz-inch)
Tape Tension Measurement
Tension meter Meter reading
CQ403A more than 90 g
CQ-403R (more than 3.18 02)
Head Height Adjustment
1. Install a mirror cassette.
(CQ-009C: Part No. 8-909-708-01)
2. In record mode and viewing from the front, ad-
just the head height to eliminate tape curl and
tape twist at portions of arrow.
3. Perform this adjustment in both FWD and REV
modes.
“Sree
erase head record/playback
head
Low
z= |2
3-573~-138-01 (t=0. 1)
a
3-573-138-11. (t=0. 2)
Shim, head height adjustment
C
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SECTION 4
ELECTRICAL ADJUSTMENTS
3-1. TAPE RECODER SECTION
eTest Tape
ee
WS.-48A 3kHz, 0dB tape speed adjustment
P-4-A063 6.3kHz, —30dB head azimuth adjustment
REC/PB Head Azimuth Adjustment
Perform adjustment in both FWD and REV modes.
After adjustment, confirm the specification
in FWD mode.
Procedure:
1. Mode: playback
test tape
P-4-A063
(6.3kHz, —10dB)
320
Headphones jack
2. Turn the adjustment screw for the maximum output
levels. If these levels do not match. turn the adjustment
screw until both of output levels match together within
3dB,
Fe within
Output 308
level
R-CH
screw peak
position L-CH R-CH angle
peak peak
3. Phase Check
Mode: playback
test tape
P.4-A063 oscilloscope
(6.3kHz, — 10d)
320
in phase - 45°
REV FWD
a OM