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MDS-SD1
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65
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Service Manual
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Device
Audio
File
mds-sd1.pdf
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Sony MDS-SD1 Service Manual ▷ View online

– 25 –
5-6. CHECKS PRIOR TO REPAIRS
These checks are performed before replacing parts according to
“approximate specifications” to determine the faulty locations. For
details, refer to “Checks Prior to Parts Replacement and
Adjustments” (See page 8).
5-6-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and room
temperature to 22 to 28 C.
Checking Procedure:
1. Rotate the  – 
˜ +  knob to display “TEMP CHECK”.
2. Press the  ENTER/YES  button.
3. “T=@@(##) [OK]” should be displayed. If “T=@@ (##) [NG]”
is displayed, it means that the results are bad.
(@@ indicates the current value set, and ## indicates the value
written in the non-volatile memory.)
5-6-2. Laser Power Check
Before checking, check the IOP value of the optical pick-up.
(Refer to 5-8. Recording and Displaying IOP Information.)
Connection :
KMS
260A
27X40
B0825
N
Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
)
Checking Procedure:
1. Set the laser power meter on the objective lens of the optical
pick-up. (When it cannot be set properly, press the  
0/≠
button or  
)/±  button to move the optical pick-up.)
Connect the digital volt meter to CN110 pin 5 (I+3V) and
CN110 pin 4 (IOP).
2. Then, rotate the  – 
˜ +  knob and display “LDPWR CHECK”.
3. Press the  ENTER/YES  button once and display “LD 0.9 mW $
”. Check that the reading of the laser power meter become
0.84 to 0.92 mW.
4. Press the  ENTER/YES  button once more and display “LD 7.0
mW $ 
”. Check that the reading the laser power meter and
digital volt meter satisfy the specified value.
Specified Value :
Laser power meter reading : 7.0 ± 0.2 mW
Digital voltmeter reading : Optical pick-up displayed value ± 10%
(Optical pick-up label)
5. Press the  MENU/NO  button and display “LDPWR CHECK”
and stop the laser emission.
(The  MENU/NO  button is effective at all times to stop the
laser emission.)
(For details of the method for checking
this value, refer to “5-8. Recording and
Displaying IOP Information”.)
5-6-3. Traverse Check
Connection :
Checking Procedure:
1. Connect an oscilloscope to CN110 pin 3 (TE) and CN110 pin
1 (VC) of the BD board.
2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the  
)/±  button and move the optical pick-up out-
side the pit.
4. Rotate the  – 
˜ +  knob and display “EF MO CHECK”.
5. Press the  ENTER/YES  button and display “EFB = 
 MO-R”.
(Laser power READ power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)
6. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not rotate the  – 
˜ +  knob.
(Read power traverse checking)
(Traverse Waveform)
7. Press the  ENTER/YES  button and display “EFB = 
 MO-W”.
8. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not rotate the  – 
˜ +  knob.
(Write power traverse checking)
(Traverse Waveform)
9. Press the  ENTER/YES  button display “EFB = 
 MO-P”.
Then, the optical pick-up moves to the pit area automatically
and servo is imposed.
Note 1: After step 4, each time the  ENTER/YES  button is pressed,
the display will be switched between “LD 0.7 mW $ 
”,
“LD 6.2 mW $ 
”, and “LD Wp                $ 
”. Nothing
needs to be performed here.
Laser power
meter
Optical pick-up
objective lens
Digital volt meter
BD board
CN110 pin 
5
 (I+3V)
CN110 pin 
4
 (IOP)
V : 0.5 V/div
H : 10 ms/div
Input : DC mode
Oscilloscope
BD board
CN110 pin 
3
 (TE)
CN110 pin 
1
 (VC)
VC
A
B
Specified value : Below 10% offset value
Offset value (%) =                  X 100  
I
A – BI
2 (A + B)
VC
A
B
Specified value : Below 10% offset value
Offset value (%) =                  X 100  
I
A – BI
2 (A + B)
– 26 –
10. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not rotate the  – 
˜ +  knob.
(Traverse Waveform)
11. Press the  ENTER/YES  button display “EF MO CHECK”
The disc stops rotating automatically.
12. Press the  
§  button and remove the disc.
13. Load the check disc (MD) TDYS-1.
14. Roteto the  – 
˜ +  knob and display “EF CD CHECK”.
15. Press the  ENTER/YES  button and display “EFB = 
 CD”.
Servo is imposed automatically.
16. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not rotate the  – 
˜ +  knob.
(Traverse Waveform)
17. Press the  ENTER/YES  button and display “EF CD CHECK”.
18. Press the  
§  button and remove the check disc (MD) TDYS-1.
Note 1 : MO reading data will be erased during if a recorded disc is
used in this adjustment.
Note 2 : If the traverse waveform is not clear, connect the oscillo-
scope as shown in the following figure so that it can be
seen more clearly.
5-6-4. Focus Bias Check
Change the focus bias and check the focus tolerance amount.
Checking Procedure :
1. Load a test disk (MDW-74/AU-1).
2. Rotate the  – 
˜ +  knob and display “CPLAY MODE”.
3. Press the  ENTER/YES  button twice and display “CPLAY MID”.
4. Press the  MENU/NO  button when “C1 = 
 AD = 
” is
displayed.
5. Rotate the  – 
˜ +  knob and display “FBIAS CHECK”.
6. Press the  ENTER/YES  button and display “ 
/
 c = 
”.
The first four digits indicate the C1 error rate, the two digits
after [/] indicate ADER, and the 2 digits after [c =] indicate the
focus bias value.
Check that the C1 error is below 220 and ADER is below 2.
7. Press the  ENTER/YES  button and display “ 
/
 b = 
”.
Check that the C1 error is below 220 and ADER is below 2.
8. Press the  ENTER/YES  button and display “ 
/
 a = 
”.
Check that the C1 error is below 220 and ADER is below 2.
9. Press the  MENU/NO  button, next press the  
§  button, and
remove the test disc.
5-6-5. C PLAY Checking
MO Error Rate Check
Checking Procedure :
1. Load a test disk (MDW-74/AU-1).
2. Rotate the  – 
˜ +  knob and display “CPLAY MODE”.
3. Press the  ENTER/YES  button and display “CPLAY MID”.
4. The display changes to “C1 = 
 AD = 
”.
5. If the C1 error rate is below 80, check that ADER is below 2.
6. Press the  MENU/NO  button, stop playback, press the  
§  but-
ton, and test disc.
CD Error Rate Check
Checking Procedure :
1. Load a check disc (MD) TDYS-1.
2. Rotate the  – 
˜ +  knob and display “CPLAY MODE”.
3. Press the  ENTER/YES  button twice and display “CPLAY MID”.
4. The display changes to “C1 = 
 AD = 
”.
5. Check that the C1 error rate is below 50.
6. Press the  MENU/NO  button, stop playback, press the  
§  but-
ton, and the test disc.
5-6-6. Self-Recording/playback Check
Prepare a continuous recording disc using the unit to be repaired
and check the error rate.
Checking Procedure :
1. Insert a recordable disc (blank disc) into the unit.
2. Rotate the  – 
˜ +  knob to display “CREC MODE”.
3. Press the  ENTER/YES  button to display the “CREC MID”.
4. When recording starts, “  
REC
  ” is displayed, this becomes
“CREC @@@@" (@@@@ is the address), and recording starts.
5. About 1 minute later, press the  MENU/NO  button to stop
continuous recording.
6. Rotate the  – 
˜ +  knob to display “C PLAY MODE”.
7. Press the  ENTER/YES  button to display “C PLAY MID”.
8. “C1 = 
 AD = 
” will be displayed.
9. Check that the C1 error becomes below 80 and the AD error
below 2.
10. Press the  MENU/NO  button to stop playback, and press the
§  button and remove the disc.
VC
A
B
Specified value : Below 10% offset value
Offset value (%) =                  X 100  
I
A – BI
2 (A + B)
VC
A
B
Specified value : Below 10% offset value
Offset value (%) =                  X 100  
I
A – BI
2 (A + B)
330 k
Oscilloscope
10pF
BD board
CN110 pin 
3
 (TE)
CN110 pin 
1
 (VC)
– 27 –
5-7. INITIAL SETTING OF ADJUSTMENT VALUE
Note:
Mode which sets the adjustment results recorded in the non-volatile
memory to the initial setting value. However the results of the
temperature compensation offset adjustment will not change to the
initial setting value.
If initial setting is performed, perform all adjustments again
excluding the temperature compensation offset adjustment.
For details of the initial setting, refer to “5-4. Precautions on
Adjustments” and execute the initial setting before the adjustment
as required.
Setting Procedure :
1. Rotate the  – 
˜ +  knob to display “ADJ CLEAR”.
2. Press the  ENTER/YES  button. “Complete!” will be displayed
momentarily and initial setting will be executed, after which “ADJ
CLEAR” will be displayed.
5-8. RECORDING AND DISPLAYING THE IOP
INFORMATION
The IOP data can be recorded in the non-volatile memory. The IOP
value on the label of the optical pickup and the IOP value after the
adjustment will be recorded. Recording these data eliminates the
need to read the label on the optical pick-up.
Recording Procedure :
1. While pressing the  ENTER/YES  button and  
π  button, con-
nect the power plug to the outlet, and release the  ENTER/YES
button and  
π  button.
2. “TEMP CHECK” will be displayed. Press the  MENU/NO  but-
ton to display “Check”.
3. Rotate the  – 
˜ +  knob to display “[Service]”, and press the
ENTER/YES  button.
4. Rotate the  – 
˜ +  knob to display “Iop.Write”, and press the
ENTER/YES  button.
5. The display becomes Ref=@@@.@ (@ is an arbitrary number)
and the numbers which can be changed will blink.
6. Input the IOP value written on the optical pick-up.
To select the number : Rotate the  – 
˜ +  knob.
To select the digit : Press the  CD SYNC/MD WM SYNC  but-
ton.
7. When the  ENTER/YES  button is pressed, the display becomes
“Measu=@@@.@” (@ is an arbitrary number).
8. As the adjustment results are recorded for the step 7 value. Leave
it as it is and press the  ENTER/YES  button.
9. “Complete!” will be displayed momentarily. The value will be
recorded in the non-volatile memory and the display will become
“Iop Write”.
Display Procedure :
1. Rotate the  – 
˜ +  knob to display “Iop.Read”.
2. “@@.@/##.#” is displayed and the recorded contents are
displayed.
@@.@ indicates the Iop value labeled on the pick-up.
##.# indicates the Iop value after adjustment
3. To end, press the  CD SYNC/MD WM SYNC  button. or  MENU/
NO  button to display “Iop Read”.
5-9. TEMPERATURE COMPENSATION OFFSET
ADJUTMENT
Save the temperature data at that time in the non-volatile memory
as 25 ˚C reference data.
Note :
1. Usually, do not perform this adjustment.
2. Perform this adjustment in an ambient temperature of 22 ˚C to
28 ˚C. Perform it immediately after the power is turned on when
the internal temperature of the unit is the same as the ambient
temperature of 22 ˚C to 28 ˚C.
3. When D101 has been replaced, perform this adjustment after the
temperature of this part has become the ambient temperature.
Adjusting Procedure :
1. Rotate the  – 
˜ +  knob and display “TEMP ADJUST”.
2. Press the  ENTER/YES  button and select the “TEMP ADJUST”
mode.
3. “TEMP = 
[OK]” and the current temperature data will be
displayed.
4. To save the data, press the  ENTER/YES  button.
When not saving the data, press the  MENU/NO  button.
5. When the  ENTER/YES  button is pressed, “TEMP = 
 SAVE”
will be displayed and turned back to “TEMP ADJUST” display
then. When the  MENU/NO  button is pressed, “TEMP AD-
JUST” will be displayed immediatelly.
Specified Value :
The “TEMP =  
” should be within “E0 - EF”, “F0 - FF”, “00 -
0F”,  “10 - 1F” and “20 - 2F”.
5-10. LASER POWER ADJUSTMENT
Check the IOP value of the optical pick-up before adjustments.
(Refer to 5-8. Recording and Displaying IOP Information.)
Connection :
Adjusting Procedure :
1. Set the laser power meter on the objective lens of the optical
pick-up. (When it cannot be set properly, press the  
0/≠
button or  
)/±  button to move the optical pick-up.)
Connect the digital volt meter to CN110 pin 5 (I+3V) and
CN110 pin 4 (IOP).
2. Rotate the  – 
˜ +  knob and display “LDPWR ADJUST”.
(Laser power : For adjustment)
3. Press the  ENTER/YES  button once and display “LD 0.9 mW $
”.
4. Rotate the  – 
˜ +  knob so that the reading of the laser power
meter becomes 0.85 to 0.91 mW. Press the  ENTER/YES  but-
ton after setting the range knob of the laser power meter, and
save the adjustment results. (“LD SAVE $ 
” will be displayed
for a moment.)
5. Then “LD 7.0 mW $ 
” will be displayed.
6. Rotate the  – 
˜ +  knob so that the reading of the laser power
meter becomes 6.9 to 7.1 mW, press the  ENTER/YES  button and
save it.
Note : Do not perform the emission with 7.0 mW more than 15
seconds continuously.
Laser power
meter
Optical pick-up
objective lens
Digital volt meter
BD board
CN110 pin 
5
 (I+3V)
CN110 pin 
4
 (IOP)
– 28 –
KMS
260A
27X40
B0825
N
Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
)
7. Then, rotate the  – 
˜ +  knob and display “LDPWR CHECK”.
8. Press the  ENTER/YES  button once and display “LD 0.9 mW $
”. Check that the reading of the laser power meter become
0.85 to 0.91 mW.
9. Press the  ENTER/YES  button once more and display “LD 7.0
mW $ 
”. Check that the reading the laser power meter and
digital volt meter satisfy the specified value.
Note down the digital voltmeter reading value.
Specified Value :
Laser power meter reading : 7.0 ± 0.1 mW
Digital voltmeter reading : Optical pick-up displayed value ± 10%
(Optical pick-up label)
10. Press the  MENU/NO  button and display “LDPWR CHECK”
and stop the laser emission.
(The  MENU/NO  button is effective at all times to stop the
laser emission.)
11. Rotate the  – 
˜ +  knob to display “Iop.Write”.
12. Press the  ENTER/YES  button. When the display becomes
Ref=@@@.@ (@ is an arbitrary number), press the  ENTER/
YES  button to display “Measu=@@@.@” (@ is an arbitrary
number).
13. The numbers which can be changed will blink. Input the Iop
value noted down at step 9.
To select the number : Rotate the  – 
˜ +  knob.
To select the digit : Press the  CD SYNC/MD WM SYNC  but-
ton.
14. When the  ENTER/YES  button is pressed, “Complete!” will
be displayed momentarily. The value will be recorded in the
non-volatile memory and the display will become “Iop Write”.
Note 1: After step 4, each time the  ENTER/YES  button is pressed,
the display will be switched between “LD 0.7 mW $ 
”,
“LD 6.2 mW $ 
”, and “LD Wp               $ 
”. Nothing
needs to be performed here.
(For details of the method for checking
this value, refer to “5-8. Recording and
Displaying IOP Information”.)
5-11. TRAVERSE  ADJUSTMENT
Connection :
Adjusting Procedure :
1. Connect an oscilloscope to CN110 pin 3 (TE) and CN110 pin
1 (VC) of the BD board.
2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the  
)/±  button and move the optical pick-up out-
side the pit.
4. Rotate the  – 
˜ +  knob and display “EF MO ADJUST”.
5. Press the  ENTER/YES  button and display “EFB = 
 MO-R”.
(Laser power READ power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)
6. Rotate the  – 
˜ +  knob so that the waveform of the oscillo-
scope becomes the specified value.
(When the  – 
˜ +  knob is rotated, the   of “EFB=  ” changes
and the waveform changes.) In this adjustment, waveform var-
ies at intervals of approx. 2%. Adjust the waveform so that the
specified value is satisfied as much as possible.
(Read power traverse adjustment)
(Traverse Waveform)
7. Press the  ENTER/YES  button and save the result of adjustment
to the non-volatile memory (“EFB = 
 SAVE” will be displayed
for a moment. Then “EFB = 
 MO-W” will be displayed).
8. Rotate the  – 
˜ +  knob so that the waveform of the oscillo-
scope becomes the specified value.
(When the  – 
˜ +  knob is rotated, the   of “EFB-  ” changes
and the waveform changes.) In this adjustment, waveform var-
ies at intervals of approx. 2%. Adjust the waveform so that the
specified value is satisfied as much as possible.
(Write power traverse adjustment)
(Traverse Waveform)
9. Press the  ENTER/YES  button, and save the adjustment results
in the non-volatile memory. (“EFB = 
 SAVE” will be displayed
for a moment.)
10. “EFB = 
 MO-P”. will be displayed.
The optical pick-up moves to the pit area automatically and servo
is imposed.
V : 0.5 V/div
H : 10 ms/div
Input : DC mode
Oscilloscope
BD board
CN110 pin 
3
 (TE)
CN110 pin 
1
 (VC)
VC
A
B
Specification A = B
VC
A
B
Specification A = B
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