Sony PMC-MD55 - Md Boombox, Руководство по обслуживанию

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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 :
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”.
3. Press the
[YES, ENTER]
button once to display “LD 0.9 mW
$ ”. Check that the reading of the laser power meter become
0.84 to 0.92 mW.
4. Press the
[YES, ENTER]
button once more to display “LD
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%
5. Press the
[NO, CANCEL]
button to display “LDPWR CHECK”
and stop the laser emission.
(The
[NO, CANCEL]
button is effective at all times to stop
the laser emission)
Note 1: After step 4, each time the
[YES, ENTER]
button is pressed,
the display will be switched “LD 0.7 mW $ ”, “LD 6.2 mW $
”, and “LD WP $ ”. Nothing needs to be performed
here.
Optical pick-up
objective lens
laser
power meter
+
–
BD board
digital voltmeter
CN110 pin
5
(I +3V)
CN110 pin
4
(IOP)
[ ]
[ ]
KMS260A
27X40
B0825
lOP=82.5 mA in this case
lOP (mA) = Digital voltmeter reading (mV)/1 (
Ω
)
(Optical pick-up label)
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”.
3. Press the
[YES, ENTER]
button twice to display “CPLAY
MID”.
4. Press the
[NO, CANCEL]
button when “C1 = AD = ”
is displayed.
5. Turn the JOG dial to display “FBIAS CHECK”.
6. Press the
[YES, ENTER]
button to 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 50 and ADER is below 2.
7. Press the
[YES, ENTER]
button to display “ / b = ”.
Check that the C1 error is about 200 and ADER is below 2.
8. Press the
[YES, ENTER]
button to display “ / a = ”.
Check that the C1 error is about 200 and ADER is below 2.
9. Press the
[NO, CANCEL]
button, then press the
[MD EJECT ]
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”.
3. Press the
[YES, ENTER]
button to 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
[NO, CANCEL]
button to stop playback, then press
the
[MD EJECT ]
button and take out the test disc.
CD Error Rate Check
Checking Procedure :
1. Load the check disc (MD) TDYS-1.
2. Turn the JOG dial to display “CPLAY MODE”.
3. Press the
[YES, ENTER]
button twice to display “CPLAY
MID”.
4. The display changes to “C1 = AD = ”.
5. Check that the C1 error rate is below 50.
6. Press the
[NO, CANCEL]
button to stop playback, then press
the
[MD EJECT ]
button and take out the check disc.
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”.
3. Press the
[YES, ENTER]
button to display “CREC MID”.
4. When recording starts, lights up “
[REC]
” and display “CREC
@@@@” (@@@@ is the address).
5. About 1 minute later, press the
[NO, CANCEL]
button to stop
continuous recording.
6. Turn the JOG dial to display “CPLAY MODE”.
7. Press the
[YES, ENTER]
button to display “CPLAY MID”.
8. “C1 = AD = ” will be displayed.
9. Check that the C1 error becomes below 80 and the ADER be-
low 2.
10. Press the
[NO, CANCEL]
button to stop playback, then press
the
[MD EJECT ]
button and take out the disc.
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