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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 “Checks Prior to Parts Replacement and
Adjustments” (See page 13).
5-6-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and room
temperature to 22 to 28°C.
Checking Procedure:
1. Press the =0/MD/CD/TUNING – button or )+/
MD/CD/TUNING + button to display “TEMP CHECK”.
2. Press the ENTER/YES “R” 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 IOP Information.)
KMS
260A
27X40
B0825
N
Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
Ω
)
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/
MD/CD/TUNING – button or )+/MD/CD/TUNING +
button continuously to move the optical pick-up.)
Connect the digital volt meter to CN110 pin 5 (I+3V) and
CN110 pin 4 (IOP).
2. Then, press the =0/MD/CD/TUNING – button or
)+/MD/CD/TUNING + button and display “LDPWR
CHECK”.
3. Press the ENTER/YES “R” button once and display “LD 0.9
mW $ ”. Check that the reading of the laser power meter be-
come 0.84 to 0.92 mW.
4. Press the ENTER/YES “R” button once more and display “LD
7.0 mW $ ”. 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%
(Optical pick-up label)
(For details of the method for checking
this value, refer to “5-8. Recording and
Displaying IOP Information”.)
5. Press the MENU/NO “R” button and display “LDPWR
CHECK” and stop the laser emission.
(The MENU/NO “R” button is effective at all times to stop the
laser emission.)
Note 1: After step 4, each time the ENTER/YES “R” button is
pressed, the display will be switched between “LD 0.7 mW
$ ”, “LD 6.2 mW $ ”, and “LD WP $ ”.
Nothing needs to be performed here.
5-6-3. Traverse Check
Connection :
Laser power
meter
Optical pick-up
objective lens
Digital volt mete
r
BD (MD) board
CN110 pin
5
(I+3V)
CN110 pin
4
(IOP)
V : 0.5 V/div
H : 10 ms/div
Input : DC mod
e
Oscilloscope
BD (MD) board
CN110 pin
3
(TE)
CN110 pin
1
(VC)
Checking Procedure:
1. Connect an oscilloscope to CN110 pin 3 (TE) and CN110 pin
1 (VC) of the BD (MD) board.
2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the )+/MD/CD/TUNING + button continuously
and move the optical pick-up outside the pit.
4. Press the =0/MD/CD/TUNING – button or )+/
MD/CD/TUNING + button and display “EF MO CHECK”.
5. Press the ENTER/YES “R” button and display “EFB = MO-
R”.
(Laser power READ power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)
6. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not press the =0/MD/CD/
TUNING – button or )+/MD/CD/TUNING + button.
(Read power traverse checking)
(Traverse Waveform)
VC
A
B
Specified value : Below 10% offset value
Offset value (%) = X 100
I
A – B
I
2 (A + B)
7. Press the ENTER/YES “R” button and display “EFB = MO-
W”.
8. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not press the =0/MD/CD/
TUNING – button or )+/MD/CD/TUNING + button.
(Write power traverse checking)
(Traverse Waveform)
VC
A
B
Specified value : Below 10% offset value
Offset value (%) = X 100
I
A – B
I
2 (A + B)