40
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 “5-1. Parts Replacement and Adjustments” (see
page 37).
5-6-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and
room temperature to 22 to 28ºC.
Procedure:
1. Turn the
[ENTER/YES]
knob to display “TEMP CHECK” (C12).
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 the Iop Information (see
page 43)
Connection:
Procedure:
1. Set the laser power meter on the objective lens of the optical
p i c k - u p . ( W h e n i t c a n n o t b e s e t p r o p e rl y, t u r n t h e
[CURSOR ]
knob to move the optical pick-
up.)
Connect the digital volt meter to CN105 pin
1
(I+3V) and
CN105 pin
2
(IOP).
2. Then, turn the
[ENTER/YES]
knob to display “LDPWR
CHECK” (C13).
3. Press the
[ENTER/YES]
button once to display “LD
0.9mW$
”. Check that the reading of the laser power meter
become 0.84 to 0.92 mW.
4. Press the
[ENTER/YES]
button once more to display “ LD
7.0mW$
”. 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%
5. Press the
[MENU/NO]
button to display “LDPWR CHECK”
(C13) and stop the laser emission.
(The
[MENU/NO]
button is effective at all times to stop the laser
emission.)
Note:
After step 4, each time the
[ENTER/YES]
button is pressed, the
display will be switched between “LD 0.7W$
”, “LD
7.5mW$
”, and “LD Wp
$
”. Nothing needs to be
performed here.
Checking Location: BD (MD) board (see page 47)
5-6-3. Iop Compare
The current Iop value at laser power 7.0 mW output and reference
Iop value (set at shipment) written in the nonvolatile memory are
compared, and the rate of increase/decrease will be displayed in
percentage.
Note:
Perform this function with the optical pick-up set at room
temperature.
Procedure:
1. Turn the
[ENTER/YES]
knob to display “Iop Compare” (C27).
2. Press the
[ENTER/YES]
button and start measurements.
3. When measurements complete, the display changes to “± xx%
yy”.
xx is the percentage of increase/decrease, and OK or NG is
displayed at yy to indicate whether the percentage of increase/
decrease is within the allowable range.
4. Press the
[MENU/NO]
button to end.
5-5.
USING THE CONTINUOUSLY RECORDED
DISC
* This disc is used in focus bias adjustment and error rate check.
The following describes how to create a continuous recording
disc.
1. Insert a disc (blank disc) commercially available.
2. Turn the
[ENTER/YES]
knob to display “CREC 2MODE” (C37).
3. Press the
[ENTER/YES]
button to display “CREC 2 MID”.
Display “CREC 2(0300” and start to recording.
4. Complete recording within 5 minutes.
5. Press the
[MENU/NO]
button and stop recording .
6. Press the
[MD ]
button and remove the disc.
The above has been how to create a continuous recorded data for
the focus bias adjustment and error rate check.
Note:
Be careful not to apply vibration during continuous recording.
laser
power meter
Z
KMS262A
20101
B0825
lOP=82.5 mA in this case
lOP (mA) = Digital voltmeter reading (mV)/1 (
Ω
)
(Optical pick-up label)
For details of the method for
checking this value, refer to
“5-8. Recording and Displaying
the Iop Information”
m
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