36
MXD-D400
5-7.
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 Adjust-
ments” (see page 13).
5-7-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and
room temperature to 22 to 28ºC.
Checking Procedure:
1. Rotate the
l
AMS
L
(MD) knob to display “TEMP
CHECK” (C12).
2. Press the
[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.)
5-7-2. Laser Power Check
Before checking, check the Iop value of the optical pick-up.
(Refer to 5-9. Recording and Displaying the Iop Information (see
page 39.)
Connection:
Checking Procedure:
1. Set the laser power meter on the objective lens of the optical
pick-up.
Connect the digital volt meter to CN105 pin
1
(I+3V) and
CN105 pin
2
(IOP).
2. Then, rotate the
l
AMS
L
(MD) knob and display
“LDPWR CHECK” (C13).
3. Press the
[YES]
button once and display “L 0.93 mW $
”.
Check that the reading of the laser power meter becomes the
specified value.
Note:
Never allow the laser emission at 8.65 mW for 1.5 seconds or longer.
Specified Value: 0.84 to 0.92 mW (KMS-262A)
0.90 to 0.96 mW (KMS-262E)
4. Press the
[YES]
button once more and display “ L 8.65 mW $
”. Check that the reading the laser power meter and digital
volt meter satisfy the specified value.
Specified Value:
Laser power meter reading : 8.1 to 8.7 mW (KMS-262A)
8.4 to 8.9 mW (KMS-262E)
Digital voltmeter reading : Optical pick-up displayed value
±
10%
(Optical pick-up label)
5. Press the
[MENU/NO]
button and 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
[YES]
button is pressed, the display
will be switched between “L 0.73 mW $
”, “L 7.70 mW $
”,
and “L Wp
$
”. Nothing needs to be performed here.
Check Location: BD (MD) board (see page 43)
5-7-3. Iop Compare
The current Iop value at laser power 8.65 mW (KMS-262E) or 8.4
mW (KMS-262A) 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. Rotate the
l
AMS
L
(MD) knob to display “Iop Com-
pare” (C27).
2. Press the
[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 this mode.
5-6.
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. Rotate the
l
AMS
L
(MD) knob and display “CREC
2MODE” (C37).
3. Press the
[YES]
button again to display “CREC 2MID”.
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
[EJECT]
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.
Optical pick-up
objective lens
laser
power meter
+
–
BD (MD) board
digital voltmeter
CN105 pin
1
(I +3 V)
CN105 pin
2
(IOP)
KMS
262E
20101
B0576
Iop = 57.6 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
Ω
)
(For details of the method for
checking this value, refer to “5-9.
Recording and Displaying the Iop
Information”.)
