Sony MDS-PC2 Service Manual ▷ View online
5
TABLE OF CONTENTS
1. SERVICING NOTE
.......................................................... 6
2. GENERAL
........................................................................ 12
3. DISASSEMBLY
3-1. Case and Front Panel .......................................................... 14
3-2. MD Mechanism .................................................................. 14
3-3. Slider (CAM) ...................................................................... 15
3-4. Base Unit (MBU-5A) BD Board ........................................ 15
3-5. SW Board and Loading Motor (M103) .............................. 16
3-2. MD Mechanism .................................................................. 14
3-3. Slider (CAM) ...................................................................... 15
3-4. Base Unit (MBU-5A) BD Board ........................................ 15
3-5. SW Board and Loading Motor (M103) .............................. 16
4. TEST MODE
..................................................................... 17
5. ELECTRICAL ADJUSTMENTS
............................... 22
6. DIAGRAMS
6-1. Circuit Boards Location ...................................................... 31
6-2. Block Diagrams
6-2. Block Diagrams
• BD Section ....................................................................... 33
• Main Section .................................................................... 34
• Main Section .................................................................... 34
6-3. Printed Wiring Board – BD Section – ................................. 36
6-4. Schematic Diagram – BD (1/2) Section – ........................... 37
6-5. Schematic Diagram – BD (2/2) Section – ........................... 38
6-6. Schematic Diagram – Main (1/2) Section – ........................ 39
6-7. Schematic Diagram – Main (2/2) Section – ........................ 40
6-8. Printed Wiring Board – Main Section – .............................. 41
6-9. Schematic Diagram – Panel Section – ................................ 42
6-10. Printed Wiring Board – Panel Section – ............................ 43
6-11. Schematic Diagram – Power Section – ............................. 44
6-12. Printed Wiring Board – Power Section – .......................... 45
6-13. Schematic Diagram – BD Switch Section – ..................... 46
6-14. Printed Wiring Board – BD Switch Section – ................... 46
6-15. IC Block Diagrams ........................................................... 46
6-15. IC Pin Functions ............................................................... 49
6-4. Schematic Diagram – BD (1/2) Section – ........................... 37
6-5. Schematic Diagram – BD (2/2) Section – ........................... 38
6-6. Schematic Diagram – Main (1/2) Section – ........................ 39
6-7. Schematic Diagram – Main (2/2) Section – ........................ 40
6-8. Printed Wiring Board – Main Section – .............................. 41
6-9. Schematic Diagram – Panel Section – ................................ 42
6-10. Printed Wiring Board – Panel Section – ............................ 43
6-11. Schematic Diagram – Power Section – ............................. 44
6-12. Printed Wiring Board – Power Section – .......................... 45
6-13. Schematic Diagram – BD Switch Section – ..................... 46
6-14. Printed Wiring Board – BD Switch Section – ................... 46
6-15. IC Block Diagrams ........................................................... 46
6-15. IC Pin Functions ............................................................... 49
7. EXPLODED VIEWS
7-1. Cabinet Section ................................................................... 53
7-2. Mechanism Section (MDM-5A) ......................................... 54
7-3. Base Unit Section (MBU-5A) ............................................. 55
7-2. Mechanism Section (MDM-5A) ......................................... 54
7-3. Base Unit Section (MBU-5A) ............................................. 55
8. ELECTRICAL PARTS LIST
........................................ 56
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing safety checks 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.
ing safety checks 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
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). Leak-
age current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers). Leak-
age 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 pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)
V, so analog meters must have an accurate low-voltage scale.
The Simpson 250 and Sanwa SH-63Trd are examples of a pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
AC
voltmeter
(0.75V)
voltmeter
(0.75V)
1.5k
Ω
0.15
µ
F
Earth Ground
To Exposed Metal
Parts on Set
Parts on Set
6
SECTION 1
SERVICING NOTE
JIG FOR CHECKING BD BOARD WAVEFORM
The special jig (J-2501-149-A) is useful for checking the waveform of the BD board. The names of terminals and the checking items to be
performed are shown as follows.
performed are shown as follows.
GND : Ground
I+3V : For measuring IOP (Check the deterioration of the optical pick-up laser)
IOP
I+3V : For measuring IOP (Check the deterioration of the optical pick-up laser)
IOP
: For measuring IOP (Check the deterioration of the optical pick-up laser)
TEO : TRK error signal (Traverse adjustment)
VC
VC
: Reference level for checking the signal
RF
: RF signal (Check jitter)
RF
VC
TEO
VC
TEO
For MDM-3
For MDM-5
IOP
I+3V
I+3V
VC
RF
TEO
IOP
I+3V
GND
RF
TEO
IOP
I+3V
GND
VC
RF
TEO
IOP
I+3V
GND
1
5
1
6
CN110
RF
5P connector
6P connector
VC
TEO
IOP
I+3V
GND
Mechanism deck
7
IOP DATA RECORDING AND DISPLAY WHEN OPTICAL PICK-UP AND NON-VOLATILE MEMORY (IC171 OF
BD BOARD) ARE REPLACED
BD BOARD) ARE REPLACED
The IOP value labeled on the optical pick-up can be recorded in the non-volatile memory. By recording the value, it will eliminate the need
to look at the value on the label of the optical pick-up. When replacing the optical pick-up or non-volatile memory (IC171 of BD board),
record the IOP value on the optical pick-up according to the following procedure.
to look at the value on the label of the optical pick-up. When replacing the optical pick-up or non-volatile memory (IC171 of BD board),
record the IOP value on the optical pick-up according to the following procedure.
Record Precedure:
1. While pressing the INPUT button and
1. While pressing the INPUT button and
p button, connect the power plug to the outlet, and release the INPUT button and p button.
2. Press the
+ button to display “[Service]”, and press the ^ “PROGRAM” button.
3. Press the
+ button to display “lop.Write”, and press the ^ “PROGRAM” button.
4. The display becomes “Ref=@@@.@” (@ is an arbitrary number) and the numbers which can be changed will blink.
5. Input the IOP value written on the optical pick-up.
5. Input the IOP value written on the optical pick-up.
To select the number : Press the
+ button.
To select the digit
: Press the
r “PROGRAM” button.
6. When the
^ “PROGRAM” button is pressed, the display becomes “Measu=@@@.@” (@ is an arbitrary number).
7. As the adjustment results are recorded for the 6 value. Leave it as it is and press the
^ “PROGRAM” button.
8. “Complete!” will be displayed momentarily. The value will be recorded in the non-volatile memory and the display will become “Iop
Write”.
9. Press the
6 “1” button to complete. “Standby” will be displayed.
Display Precedure:
1. While pressing the INPUT button and
1. While pressing the INPUT button and
p button, connect the power plug to the outlet, and release the INPUT button and p button.
2. Press the
+ button to display “[Service]”, and press the ^ “PROGRAM” button.
3. Press the
+ button to display “lop.Read”, and press the ^ “PROGRAM” button.
4. “@@.@/##.#” is displayed and the recorded contents are displayed.
@@.@ : indicates the Iop value labeled on the pick-up.
##.#
##.#
: indicates the Iop value after adjustment
5. To end, press the
r “PROGRAM” button or p “PROGRAM” button to display “Iop Read”. Then press the 6 “1” buttun.
*Note:
As this unit has only a few buttons, one button is assigned with several functions in the test mode.
Press the INPUT button to switch the functions.
Each time the INPUT button is pressed, the display switches in the following order; “PROGRAM”
As this unit has only a few buttons, one button is assigned with several functions in the test mode.
Press the INPUT button to switch the functions.
Each time the INPUT button is pressed, the display switches in the following order; “PROGRAM”
n “1” n blank n “PROGRAM”
The functions of each button change with the display.
For simplicity, operations of the INPUT button will not be described here.
Instead, symbols are added to the names of buttons. Press the INPUT button as required to switch the display.
For simplicity, operations of the INPUT button will not be described here.
Instead, symbols are added to the names of buttons. Press the INPUT button as required to switch the display.
Example)
p “PROGRAM” : Display “PROGRAM” and press the p button. p “1” : Display “1” and press the p button.
8
CHECKS PRIOR TO PARTS REPLACEMENT AND ADJUSTMENTS
Before performing repairs, perform the following checks to determine the faulty locations up to a certain extent.
Details of the procedures are described in “5 Electrical Adjustments”.
Details of the procedures are described in “5 Electrical Adjustments”.
Note:
The criteria for determination above is intended merely to determine if satisfactory or not, and does not serve as the specified value for
adjustments.
When performing adjustments, use the specified values for adjustments.
adjustments.
When performing adjustments, use the specified values for adjustments.
• 0.9 mW power
Specified value : 0.84 to 0.92 mW
• 7.0 mW power
Specified value : 6.8 to 7.2 mW
lop (at 7mW)
lop (at 7mW)
• Labeled on the optical pickup
Iop value ± 10mA
• Traverse waveform
Specified value : Below 10% offset
• Error rate check
Specified value : For points a, b, and c
C1 error : Below 220
AD error : Below 2
C1 error : Below 220
AD error : Below 2
• Error rate check
Specified value:
a.When using test disc (MDW-74/AU-1)
a.When using test disc (MDW-74/AU-1)
C1 error : Below 80
AD error : Below 2
AD error : Below 2
b.When using check disc (TDYS-1)
C1 error : Below 50
• CPLAY error rate check
Specified value:
C1 error : Below 80
AD error : Below 2
C1 error : Below 80
AD error : Below 2
• Unsatisfactory if displayed as T=@@ (##) [NG”
NG
(@@, ## are both arbitrary numbers)
(@@, ## are both arbitrary numbers)
Laser power check
(5-6-2 : See page 37)
(5-6-2 : See page 37)
Traverse check
(5-6-3 : See page 37)
Focus bias check
(5-6-4 : See page 38)
(5-6-3 : See page 37)
Focus bias check
(5-6-4 : See page 38)
C PLAY check
(5-6-5 : See page 38)
(5-6-5 : See page 38)
Self-recording/playback
check
(REC/PLAY)
(5-6-6 : See page 38)
check
(REC/PLAY)
(5-6-6 : See page 38)
TEMP check
(Temperature
compensation
offset check)
(5-6-1 : See page 37)
(Temperature
compensation
offset check)
(5-6-1 : See page 37)
Criteria for Determination
(Unsatisfactory if specified value is not satisfied)
(Unsatisfactory if specified value is not satisfied)
• Clean the optical pick-up
• Adjust again
• Replace the optical pick-up
• Adjust again
• Replace the optical pick-up
• Replace the optical pick-up
• Replace the optical pick-up
• Replace the optical pick-up
• Replace the optical pick-up
If always unsatisfactory:
• Replace the overwrite head
• Check for disconnection of the circuits around the
• Replace the overwrite head
• Check for disconnection of the circuits around the
overwrite head
If occasionally unsatisfactory:
• Check if the overwrite head is distorted
• Check the mechanism around the sled
• Check for disconnection of the circuits around D101
• Check if the overwrite head is distorted
• Check the mechanism around the sled
• Check for disconnection of the circuits around D101
(BD board)
• Check the signals around IC101, IC121, CN102,
CN103 (BD board)
Measure if unsatisfactory:
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