TEST MODE-2/3
The servo circuit of this model has been designed to be free of adjustments and controlled within the IC. Therefore, adjustments and disk judgement are performed automatically every time the TOC is read out. The adjustment status of each servo inside the IC can be monitored in this test mode.
1. Startup procedure
1) Short the test land. 2) Insert the AC plug. 3) Press the STOP button. (The test mode starts.) Note 1) The test mode is canceled by disconnecting the AC plug. Note 2) The OPEN/CLOSE switch cannot be operated during the test mode.
2. Checking the RF level
Test point: RF & VC (Vref) Test disk: TCD-782 Play back the disk and confirm that the RF waveform is in the following state:
0.8Vp-p or more
VOLT/DIV:200mV TIME/DIV:0.5us
3. Checking each servo
The adjustment values of each servo can be checked by pressing the MODE button repeatedly during playback. The switching procedure is as follows. Check mode OFF�Vref offset (RO)�focus offset (FO)�tracking offset (TO)�tracking balance (TB)�tracking gain (TG) � focus gain (FG)�focus bias (FB)�check mode OFF Example: Tracking offset (TO) Adjustment value�F5
RNDM
RESUME 1 DSL
Tracking offset
Adjustment value
* Adjustment values are indicated in hexadecimal. When displaying each mode on the LCD and pressing the PLAY button in the STOP status, the center value is displayed on the LCD. After the disk starts rotating, the adjustment value that was set during automatic adjustment is displayed. The display range of the center values and adjustment values of each mode are as follows. There are 256 steps for displaying the values of all modes. Center value 1) Vref offset (RO) 2) Focus offset (FO) 3) Tracking offset (TO) 4) Tracking balance (TB) 5) Tracking gain (TG) 6) Focus gain (FG) 7) Focus bias (FB) Center value 00 00 00 80 40 40 00 Display range 80-7F 80-7F 80-7F 00-FF 00-FF 00-FF 80-7F
