Sony HCD-J3MD Service Manual page 36

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 14).
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 lm/TUNING – button or ML/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".)
Connection :
Optical pick-up
objective lens
BD (MD) board
CN110 pin 5 (I+3V)
CN110 pin 4 (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 lm/
TUNING – button or ML/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 lm/TUNING – button or ML/
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
become 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 of 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
KMS
260A
this value, refer to "5-8. Recording and
27X40
Displaying IOP Information".)
B0825
Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 ( Ω )
36
5.
Note 1: After step 4, each time the ENTER/YES "R" button is
5-6-3. Traverse Check
Connection :
Checking Procedure:
1. Connect an oscilloscope to CN110 pin 3 (TE) and CN110 pin
Laser power
meter
2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the ML/TUNING + button continuously and move
4. Press the lm/TUNING – button or ML/TUNING +
5. Press the ENTER/YES "R" button and display "EFB =
Digital voltmeter
6. Observe the waveform of the oscilloscope, and check that the
7. Press the ENTER/YES "R" button and display "EFB =
8. Observe the waveform of the oscilloscope, and check that the
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.)
pressed, the display will be switched between "LD 0.7 mW
$ ", "LD 6.2 mW $
Nothing needs to be performed here.
BD (MD) board
CN110 pin 3 (TE)
CN110 pin 1 (VC)
1 (VC) of the BD board.
the optical pick-up outside the pit.
button and display "EF MO CHECK".
R".
(Laser power READ power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)
specified value is satisfied. Do not press the lm/TUNING
– button or ML/TUNING + button.
(Read power traverse checking)
(Traverse Waveform)
VC
Specified value : 10% or less of the offset value
IA – BI
Offset value (%) = X 100
2 (A + B)
W".
specified value is satisfied. Do not press the lm/TUNING
– button or ML/TUNING + button.
(Write power traverse checking)
(Traverse Waveform)
VC
Specified value : 10% or less of the offset value
IA – BI
Offset value (%) = X 100
2 (A + B)
", and "LD WP $
Oscilloscope
V : 0.5 V/div
H : 10 ms/div
Input : DC mode
MO-
A
B
MO-
A
B
".