Sony PMC-MD55 Service Manual page 23

6. CHECK 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 Adjust-
ments" (See page 5).
6-1. Laser Power Check
Connection :
Optical pick-up
objective lens
BD board
CN110 pin 5 (I +3V)
CN110 pin 4 (IOP)
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 but-
ton or ) button to move the optical pick-up)
[ ]
Connect the digital voltmeter to CN110 pin 5 (I+3V) and
CN110 pin 4 (IOP) on the BD board.
2. Then, turn the JOG dial to display "LDPWR CHECK".
[YES, ENTER]
3. Press the
$ ". Check that the reading of the laser power meter become
0.84 to 0.92 mW.
[YES, ENTER]
4. Press the
7.0 mW $ ". Check that the reading the laser power meter
and digital voltmeter satisfy the specified value.
Specified Value:
Laser power meter reading: 7.0 ± 0.2 mW
Digital voltmeter reading : Value on the optical pick-up label
±10%
(Optical pick-up label)
KMS260A
27X40
B0825
lOP=82.5 mA in this case
lOP (mA) = Digital voltmeter reading (mV)/1 ( Ω )
[NO, CANCEL]
5. Press the button to display "LDPWR CHECK"
and stop the laser emission.
[NO, CANCEL]
(The button is effective at all times to stop
the laser emission)
Note 1: After step 4, each time the
the display will be switched "LD 0.7 mW $
", and "LD WP
here.
laser
power meter
digital voltmeter
+
–
[ ]
button once to display "LD 0.9 mW
button once more to display "LD
[YES, ENTER]
button is pressed,
", "LD 6.2 mW $
$ ". Nothing needs to be performed
6-2. Focus Bias Check
Change the focus bias and check the focus tolerance amount.
Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
2. Turn the JOG dial to display "CPLAY MODE".
[YES, ENTER]
3. Press the
MID".
[NO, CANCEL]
4. Press the
is displayed.
5. Turn the JOG dial to display "FBIAS CHECK".
[YES, ENTER]
6. Press the
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 50 and ADER is below 2.
[YES, ENTER]
7. Press the
Check that the C1 error is about 200 and ADER is below 2.
[YES, ENTER]
8. Press the
Check that the C1 error is about 200 and ADER is below 2.
[NO, CANCEL]
9. Press the
button and take out the test disc.
6-3. C PLAY Check
MO Error Rate Check
Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
2. Turn the JOG dial to display "CPLAY MODE".
[YES, ENTER]
3. Press the
4. The display changes to "C1 =
5. If the C1 error rate is below 80, check that ADER is below 2.
[NO, CANCEL]
6. Press the
[MD EJECT ]
the
CD Error Rate Check
Checking Procedure :
1. Load the check disc (MD) TDYS-1.
2. Turn the JOG dial to display "CPLAY MODE".
[YES, ENTER]
3. Press the
MID".
4. The display changes to "C1 =
5. Check that the C1 error rate is below 50.
[NO, CANCEL]
6. Press the
6
[MD EJECT ]
the
6-4. Self-Recording/playback Check
Prepare a continuous recording disc using the unit to be repaired
and check the error rate.
Checking Procedure :
1. Load a recordable disc (blank disc).
2. Turn the JOG dial to display "CREC MODE".
[YES, ENTER]
3. Press the
4. When recording starts, lights up "
@@@@" (@@@@ is the address).
5. About 1 minute later, press the
continuous recording.
6. Turn the JOG dial to display "CPLAY MODE".
[YES, ENTER]
7. Press the
8. "C1 = AD =
9. Check that the C1 error becomes below 80 and the ADER be-
low 2.
[NO, CANCEL]
10. Press the
[MD EJECT ]
the
– 23 –
button twice to display "CPLAY
button when "C1 =
button to display "
button to display "
button to display "
[MD EJECT ]
button, then press the
button to display "CPLAY MID".
AD = ".
button to stop playback, then press
6
button and take out the test disc.
button twice to display "CPLAY
AD = ".
button to stop playback, then press
button and take out the check disc.
button to display "CREC MID".
[REC]
" and display "CREC
[NO, CANCEL]
button to display "CPLAY MID".
" will be displayed.
button to stop playback, then press
6
button and take out the disc.
AD = "
/ c = ".
/ b = ".
/ a = ".
6
button to stop