C Play Check; Focus Bias Check; Self-Recording/Playback Check - Sony MDS-SP55 Service Manual

10. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not rotate the m button or
M button.
(Traverse Waveform)
VC
Specified value : Below 10% offset value
IA – BI
Offset value (%) = X 100
2 (A + B)
11. Press the ENTER/YES button display "MD EF MO CHECK"
The disc stops rotating automatically.
12. Press the A button and remove the disc.
13. Load the check disc (MD) TDYS-1.
14. Roteto the l L knob and display "MD EF CD CHECK".
15. Press the ENTER/YES button and display "MD 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 m button or
M button.
(Traverse Waveform)
VC
Specified value : Below 10% offset value
IA – BI
Offset value (%) =
2 (A + B)
17. Press the ENTER/YES button and display "MD EF CD
CHECK".
18. Press the A 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.
330 kΩ
BD board
CN110 pin 3 (TE)
CN110 pin 1 (VC)
A
B
A
B
X 100
Oscilloscope
10pF

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/GA-1).
2. Rotate the l L knob and display "MD CPLAY MODE".
3. Press the ENTER/YES button twice and display "MD CPLAY
MID".
4. Press the MENU/NO button when "MD C =
displayed.
5. Rotate the l L knob and display "FBIAS CHECK".
6. Press the ENTER/YES button and display "MD
".
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 "MD
".
Check that the C1 error is below 220 and ADER is below 2.
8. Press the ENTER/YES button and display "MD
".
Check that the C1 error is below 220 and ADER is below 2.
9. Press the MENU/NO button, next press the A button, and
remove the test disc.

5-6-5. C PLAY Check

MO Error Rate Check
Checking Procedure :
1. Load a test disk (MDW-74/GA-1).
2. Rotate the l L knob and display "MD CPLAY MODE".
3. Press the ENTER/YES button and display "MD CPLAY MID".
4. The display changes to "MD C1 =
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 A but-
ton, and test disc.
CD Error Rate Check
Checking Procedure :
1. Load a check disc (MD) TDYS-1.
2. Rotate the l L knob and display "MD CPLAY MODE".
3. Press the ENTER/YES button twice and display "MD CPLAY
MID".
4. The display changes to "MD C1 =
5. Check that the C1 error rate is below 50.
6. Press the MENU/NO button, stop playback, press the A 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 l L knob to display "MD CREC MODE".
3. Press the ENTER/YES button to display the "MD CREC MID".
4. When recording starts, this becomes "MD CREC (@@@@)"
(@@@@ is the address), and recording starts.
5. About 1 minute later, press the MENU/NO button to stop con-
tinuous recording.
6. Rotate the l L knob to display "MD CPLAY MODE".
7. Press the ENTER/YES button to display "MD CPLAY MID".
8. "MD 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
A button and remove the disc.
AD = " is
/ c =
/ b =
/ a =
AD = ".
AD = ".
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