Read Sony CMT-EH12 / HCD-EH12 Service Manual online
2
HCD-EH12
Notes on chip component replacement
•
Never reuse a disconnected chip component.
•
Notice that the minus side of a tantalum capacitor may be
damaged by heat.
Flexible Circuit Board Repairing
•
Keep the temperature of the soldering iron around 270 ˚C
during repairing.
•
Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
•
Be careful not to apply force on the conductor when soldering
or unsoldering.
1.
SERVICING NOTES
...............................................
3
2.
GENERAL
...................................................................
4
3.
DISASSEMBLY
3-1.
Disassembly Flow ...........................................................
6
3-2.
Rear Cabinet Section .......................................................
6
3-3.
Front Cabinet Section, Top Cabinet Section and
MAIN Board ....................................................................
MAIN Board ....................................................................
7
3-4.
Mechanical Deck (H-21SB) ............................................
7
3-5.
Base Unit Section (BU-K8BD83S-WOD) ......................
8
3-6.
Optical Pick-up Block (KSM-213CDP) ..........................
8
4.
TEST MODE
..............................................................
9
5.
MECHANICAL ADJUSTMENTS
....................... 10
6.
ELECTRICAL ADJUSTMENTS
......................... 10
7.
DIAGRAMS
7-1.
Block Diagram – CD SERVO Section – ......................... 14
7-2.
Block Diagram – TUNER Section – ............................... 15
7-3.
Block Diagram – MAIN Section – .................................. 16
7-4.
Printed Wiring Board – CD Board – ............................... 18
7-5.
Schematic Diagram – CD Board – .................................. 19
7-6.
Printed Wiring Boards – MAIN Section – ...................... 20
7-7.
Schematic Diagram – MAIN Section (1/3) – .................. 21
7-8.
Schematic Diagram – MAIN Section (2/3) – .................. 22
7-9.
Schematic Diagram – MAIN Section (3/3) – .................. 23
7-10. Printed Wiring Board – PANEL Board – ........................ 24
7-11. Schematic Diagram – PANEL Board – ........................... 25
7-11. Schematic Diagram – PANEL Board – ........................... 25
8.
EXPLODED VIEWS
8-1.
Overall Section ................................................................ 33
8-2.
Front Cabinet Section ...................................................... 34
8-3.
Top Cabinet Section ........................................................ 35
8-4.
Base Unit Section (BU-K8BD83S-WOD) ...................... 36
9.
ELECTRICAL PARTS LIST
................................ 37
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation
exposure.
other than those specified herein may result in hazardous radiation
exposure.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK
0
OR DOTTED LINE
WITH MARK
0
ON THE SCHEMATIC DIAGRAMS AND IN
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR
IN SUPPLEMENTS PUBLISHED BY SONY.
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR
IN SUPPLEMENTS PUBLISHED BY SONY.
TABLE OF CONTENTS
SAFETY CHECK-OUT
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.
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 microamperes.).
Leakage current can be measured by any one of three methods.
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microamperes.).
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.
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” indication
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)
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)
Fig. A.
Using an AC voltmeter to check AC leakage.
1.5 k
Ω
0.15
µ
F
AC
voltmeter
(0.75 V)
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Parts on Set
Earth Ground
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