CFD-S250 - Sony Audio Service Manual (repair manual). Page 3

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3-1.   Cabinet (Upper) Assy .......................................................... 7
3-2.   Cabinet (Front) Assy, Cabinet (Rear) Assy ......................... 7
3-3.   Wires ................................................................................... 8
3-4.   MD Block ............................................................................ 8
3-5.   Holder (Cassette) ................................................................. 9
3-6.   LCD Board .......................................................................... 9
3-7.   Main Board ....................................................................... 10
3-8.   Tuner Board ....................................................................... 10
3-9.   Power Board ...................................................................... 11
3-10. CD Lid ............................................................................... 11
3-11. CD Block Assy .................................................................. 12
3-12. Optical Pick-up ................................................................. 12
3-13. R/P Head (HRP301), TC Board ........................................ 13
3-14. Motor Assy (M801), Main Belt (B), Sub Belt (B) ............ 13

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Tape Section .......................................................................... 14
Tuner Section ......................................................................... 15
CD Section ............................................................................ 16

6-1.   IC Pin Description ............................................................. 17
6-2.   Circuit Boards Location .................................................... 17
6-3.   Block Diagram – CD Section – ......................................... 18
6-4.   Block Diagram – Main Section – ...................................... 19
6-5.   Printed Wiring Board – CD Section – ............................... 20
6-6.   Schematic Diagram – CD Section – .................................. 21
6-7.   Printed Wiring Board – Tuner Section – ........................... 22
6-8.   Schematic Diagram – Tuner Section – .............................. 23
6-9.   Printed Wiring Boards – Main Section – .......................... 24
6-10. Schematic Diagram – Main Section (1/2) – ...................... 25
6-11. Schematic Diagram – Main Section (2/2) – ...................... 26
6-12. Printed Wiring Board – TC Section – ............................... 27
6-13. Schematic Diagram – TC Section – .................................. 28
6-14. Printed Wiring Boards – Control Section – ....................... 29
6-15. Schematic Diagram – Control Section – ........................... 30
6-16. Printed Wiring Boards – Power Supply Section – ............ 31
6-17. Schematic Diagram – Power Supply Section – ................. 32
6-18. IC Block Diagrams ............................................................ 33

7-1.   Main Section ..................................................................... 36
7-2.   Cabinet (Front) Section ..................................................... 37
7-3.   Cabinet (Upper) (1) Section .............................................. 38
7-4.   Cabinet (Upper) (2) Section .............................................. 39
7-5.   Cabinet (Rear) Section ...................................................... 40
7-6.   Tape Mechanism Section .................................................. 41
7-7.   CD Mechanism Section .................................................... 42

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SAFETY  CHECK-OUT (US MODEL)
After correcting the original service problem, perform the following
safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage.
Check leakage as described below.

LEAKAGE  TEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA

WT-540A. Follow the manufacturers’ instructions to use these
instruments.

2. A battery-operated AC milliammeter. The Data Precision 245

digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a

VOM or battery-operated AC voltmeter. The “limit” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are
examples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are
suitable.  (See Fig. A)

1.5 k

Ω

0.15 

µ

F

AC
voltmeter
(0.75 V)

To Exposed Metal
Parts on Set

Earth Ground