Home Position Detection - Sony DVP S530D Training Manual

Sled Stepping Motor
Name
Channel 1 STVC (ref)
Channel 2 SLDA (inward)
Channel 3 SLDB (outward)
Time base
The sled motor can be driven manually in either direction to produce the
waveforms shown by using the test mode's manual servo control.
Sled Driver IC802 Sends Voltages to the Stepper Sled Motor
When the input pulses to pulse Sled motor Driver IC802 are not identical
to the input reference, the sled motor is driven. At the output, if pulses to
the B coil of the stepper type sled motor are lower than the pulses applied
to the A coil, the sled moves the laser outward. This can be seen in the
waveforms taken at IC802's output.
Sled Motor Waveforms
All four sled motor drive signals in these waveforms show that the B coil of
the stepper motor gets a reduced amplitude pulse to move the laser as-
sembly outward.
P M 3 3 9 4 , F L U K E & P H I L I P S
c h 1
c h 2
1
c h 3
c h 4 2
T
3
C H 1 ! 5 . 0 0 V =
C H 2 ! 5 . 0 0 V =
C H 3 ! 5 . 0 0 V =
4
C H 4 ! 5 . 0 0 V = C H P M T B 5 0 . 0 m s - 1 . 3 4 d v c h 3 -
Outward Sled Drive Waveforms
Name
Channel 1 B coil -
Channel 2 B coil +
Channel 3 A coil -
Channel 4 A coil +
Time base
Location Voltage/div
IC701/pin 7 2Vp-p
IC701/pin 9 2Vp-p
IC701/pin 8 2Vp-p
5usec/div.
S T O P
Location Voltage/div
CN003/pin 11 5Vp-p
CN003/pin 8 5Vp-p
CN003/pin 7 5Vp-p
CN003/pin 9 5Vp-p
50msec/div.
45
Sled Drive Mute/Inhibit
The sled and loading motors are inhibited when the tray is out. IC601
performs this operation by grounding IC802/pin 9 to stop the driver IC802.
Driver IC 802/pin 9 Mute/Inhibit
IC802/pin 9 Voltage
2.3V = normal operation
0V = tray loading and sled motors inhibited

Home Position Detection

The laser assembly's home position is identified by a in-limit photodetec-
tor within the assembly. The photodetector consists of an IR LED and a
photo transistor. Light from the LED passes through an open area to
turn on the phototransistor, placing CN003/pin 11 at ground level. When
the laser assembly arrives at home position, it blocks the light, permit-
ting IC701/pin 23 to go high. IC701 relays this information to Syscon
IC201, via IC601 and home is identified.
The verification of this detector is important to determine if IC202 can
complete the initial check sequence and remain powered ON.
1. Place the unit in the special test mode (From power OFF, Press front
panel buttons RETURN and STOP together. Press MENU on the
remote. The unit will power up if IC201 and the power supply are
OK).
2. Measure the voltage at MB-85 board, CN003/pin 11.
· 3V = Laser at home (by the spindle motor)
· 0V = Laser away from home
3. You can manually push the metal laser base to slide the laser.
Mode
Tray closed
Tray open