Sony RCD-W3 Service Manual page 17

CD-R LD Setting Check
(VRDC/VWDC/FPD Level Value Check)
This routine is for checking performances of the record/playback D-A converter (IC304), the encoder/decoder IC
(IC301), CPLD (IC207), the optical pick-up block (KRS-220C), the microcomputer(IC203) and so on.
It diagnoses malfunctions of interface, the pick-up or so on.
It diagnoses the circuit in the recording mode without disc.
Description of each item
OFF LEVEL: In case of the laser turns off, FPDO output is 3V. Sampling value at this time.
VRDC LEVEL: APC circuit VRDC signal sampling value after READ power setting.
VRDC FPD: Optical pick-up FPDO signal sampling value after READ power setting.
VWDC1 LEVEL:APC circuit VWDC signal sampling value after setting WRITE power to regular value.
VWDC1 FPD: Optical pick-up FPDO signal sampling value after setting WRITE power to regular value.
VWDC2-1 FPD: There are two types of characteristics because of a non-linearity period of laser diode in the
over drive portion. This is FPDO sampling value in case of setting one of them to VWDC2 value.
VWDC2-2 FPD: FPDO sampling value in case of setting the other to VWDC2 value.
Specification of each item
38400-3300<OFF_LEVEL<38400+3300 (3.0±0.25V)
10<VRDC_LEVEL<20000
880<VRDC_FPD<1320
2000<VWDC1_LEVEL<25000
6160<VWDC1_FPD<12960
10<VWDC2-1_FPD<15000
2500<VWDC2-2_FPD<20000
Procedure:
1. Eject a disc from CD-R.
2. Select "Laser Inspection" on "LD Inspection" pull-down menu, then "Laser Power Test" window is open.
3. Click Trigger to execute LD check.
4. LD checked results are displayed.
("OK"/"NG" is displayed for every items.)
5. Click X to close "Laser Power Test" window.
Fig 3 : LD inspection menu windows
CD-R LD Power Setting
(VRDC/VWDC1 Resetting)
The optical pick-up and ICs in the circuit have a characteristics individually. In this routine, the parameters related to the
recording/playback power are actually measured and set properly.
The parameters are VRDC, VWDC1, VWDC2, VWDC2 Offset and so on. The reading power and playback power are set
properly by computing the related parameters on the basis of actually measuring values.
The preset parameters are used on power setting in case of performing Read/Write CD-R, CD-RW and so on.
Actual operation: The microcomputer receives serial data, then executes the related performances, and send parameter values to PC.
PC checks its related parameters and judges OK/NG.
Fig 4 : Laser power test window
RCD-W3
17