28
MDS-NT1
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 10).
5-7-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and
room temperature to 22 to 28ºC.
Checking Procedure:
1. Click the
[JOG UP]
or
[JOG DOWN]
to display “TEMP
CHECK” (C12).
2. Click the
[ENTER/YES]
.
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 31)
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, click the
[JOG UP]
or
[JOG DOWN]
and display
“LDPWR CHECK” (C13).
3. Click the
[ENTER/YES]
once and display “L 0.90 mW $
”.
Check that the reading of the laser power meter become speci-
fied value.
Specified Value:
Laser power meter reading : 0.84 to 0.92 mW (KMS-262A)
0.90 to 0.96 mW (KMS-262E)
4. Click the
[ENTER/YES]
once more and display “L 8.40 mW $
” (KMS-262A) or “L 8.65 mW $
” (KMS-262E). Check
that the reading the laser power meter and digital volt meter sat-
isfy the specified value.
Specified Value:
Laser power meter reading : 8.4
±
0.3 mW (KMS-262A)
8.65
±
0.25 mW (KMS-262E)
Digital voltmeter reading : Optical pick-up displayed value
±
10%
(Optical pick-up label)
5. Click the
[MENU/NO]
and display “LDPWR CHECK” (C13)
and stop the laser emission.
(The
[MENU/NO]
is effective at all times to stop the laser emis-
sion)
Note:
After step 4, each time the
[ENTER/YES]
is clicked, the display
will be switched between “L 0.70 mW $
” and “L 7.50 mW $
”, Nothing needs to be performed here.
Checking Location: BD board (see page 35)
5-7-3. Iop Compare
The current Iop value at laser power 8.4 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. Click the
[JOG UP]
or
[JOGDOWN]
to display “Iop Compare”
(C27).
2. Click the
[ENTER/YES]
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. Click the
[MENU/NO]
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. Check the
[JOG UP]
or
[JOG DOWN]
and display
“CREC 2MODE” (C37).
3. Click the
[ENTER/YES]
again to display “CREC 2MID”.
Display “CREC 2 (0300)” and start to recording.
4. Complete recording within 5 minutes.
5. Click the
[MENU/NO]
and stop recording .
6. Click the
[EJECT]
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 board
digital voltmeter
CN105 pin
1
(I +3 V)
CN105 pin
2
(Iop)
KMS
262A
20101
B0825
Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
Ω
)
(For details of the method for
checking this value, refer to “6-9.
Recording and Displaying the Iop
Information”)
