Sony MDS-PC3 - Manual (Page 27)

27
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 Adjust-
ments” (See page 8).
5-6-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and room
temperature to 22 to 28ºC.
Checks cannot be performed properly if performed after some time
from power ON due to the rise in the temperature of the IC and
diode, etc. So, perform the checks again after waiting some time.
Checking Procedure:
1. Rotate the AMS knob to display “TEMP CHECK” (C12).
2. Press the @/1 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 Iop value of the optical pick-up.
(Refer to 5-8. Recording and Displaying Iop Information.)
Connection :
KMS 260B
20101
H0576
Iop = 57.6 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (
Ω )
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 AMS knob and display “LDPWR CHECK”
(C13).
3. Press the @/1 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 @/1 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)
5. Press the x/Z button and display “LDPWR CHECK” (C13)
and stop the laser emission.
(The x/Z button is effective at all times to stop the laser
emission.)
(For details of the method for checking
this value, refer to “5-8. Recording and
Displaying Iop Information”.)
Note 1: After step 4, each time the @/1 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.
Laser power
meter
optical pick-up
objective lens
Digital volt meter
BD board
CN105 pin 1 (I+3V)
CN105 pin 2 (Iop)
R
5-5. 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 AMS knob and display “CREC 1MODE” (C35).
3. Press the @/1 button again to display “CREC1 MID”.
Display “CREC (0300)” and start to recording.
4. Complete recording within 5 minutes.
5. Press the x/Z button and stop recording .
6. Press the x/Z“PGM” 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.
5-6-3. Iop Compare
The current Iop value at laser power 7 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. Rotate the AMS knob to display “Iop Compare” (C27).
2. Press the @/1 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 x/Z button to end.