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5. 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 10)
5-1. Temperature Compensation Offset Check
When performing adjustments, the set internal temperature and
room temperature of 22 °C to 28 °C.
Checking Procedure:
1. Turn the ≠↔± dial to display "TEMP CHECK".
[ENTER/YES]
2. Press the
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)
5-2. Laser Power Check
Before checking, check the IOP value of the optical pick-up.
(Refer to 7. Recording and Displaying IOP Information)
Connection :
Optical pick-up
objective lens
BD (MD) board
TP170 (I +3V)
TP169 (IOP)
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 button
or ) button to move the optical pick-up)
Connect the digital volt meter to TP170 (I+3V) and TP169
(IOP).
2. Then, turn the ≠↔± dial to display "LDPWR
CHECK" (C02).
[ENTER/YES]
3. Press the
$
". Check that the reading of the laser power meter become
0.84 to 0.92 mW.
[ENTER/YES]
4. Press the
7.0 mW $
". Check that the reading the laser power meter
and digital volt meter satisfy the specified value.
Specifications:
Laser power meter reading: 7.0 ± 0.2 mW
Digital voltmeter reading : Optical pick-up displayed value
±10%
(Optical pick-up label)
KMS260A
27X40
B0567
lOP=56.7 mA in this case
lOP (mA) = Digital voltmeter reading (mV)/1 ( Ω )
[MENU/NO]
5. Press the
button to display "LDPWR CHECK"
and stop the laser emission.
[MENU/NO]
(The
button is effective at all times to stop the
laser emission)
button.
laser
power meter
digital voltmeter
+
–
button once to display "LD 0.9 mW
button once more to display "LD
Note 1: After step 4, each time the
the display will be switched between "LD 0.7 mW $
6.2 mW $
", and "LD Wp
performed here.
5-3. Traverse Check
Note 1: Data will be erased during MO reading if a recorded disc is
used in this adjustment.
Note 2: If the traverse waveform is not clear, connect the oscilloscope
as shown in the following figure so that it can be seen more
clearly.
BD (MD) board
TP233 (TEO)
TP167 (VC)
Connection :
BD (MD) board
TP233 (TEO)
TP167 (VC)
Checking Procedure:
1. Connect an oscilloscope to TP233 (TEO) and TP167 (VC).
2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the ) button and move the optical pick-up outside
the pit.
4. Turn the ≠↔± dial to display "EF MO CHECK"(C03).
[ENTER/YES]
5. Press the
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 turn the ≠↔± dial.
(Read power traverse checking)
(Traverse Waveform)
VC
Specified value : Below 10% offset value
Offset value (%) =
[ENTER/YES]
7. Press the
W".
8. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not turn the ≠↔± dial.
(Write power traverse checking)
(Traverse Waveform)
VC
Specified value : Below 10% offset value
Offset value (%) =
– 33 –
[ENTER/YES]
button is pressed,
$
". Nothing needs to be
oscilloscope
(DC range)
330 k Ω
+
–
10 pF
oscilloscope
(DC range)
+
V: 0.5 V/div
–
H: 10 ms/div
button to display "EFB =
A
B
I A – B I
X 100
2 (A + B)
button to display "EFB =
A
B
I A – B I
X 100
2 (A + B)
", "LD
MO-
MO-
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