- Remove the two screws and the mechanism’s top cover to expose the tray and laser platform.
- Locate the top pawl under the tray by inserting a small screwdriver between the platform and tray. The pawl is just in front of the spindle motor.
- Slide the pawl to the right to lower the platform and free the tray.
- Remove the tray.
Tilt Motor: Purpose
- Maximum RF output level occurs when the laser beam is perpendicular to the disc’s information layer. The tilt motor raises one end of the laser platform so its beam is perpendicular to the disc.
- The tilt motor is a stepping motor located next to the incline gear. At power OFF, the incline gear lowers one end of the laser platform. At power ON, the incline gear raises the platform to full height.
The stepping motor then increments the incline
gear to the middle position. This
position is stored in EEProm IC201 and updated during the test mode automatic
adjustments. During DVD playback, if the RF level fluctuates, the tilt motor
rotates until the RF level stabilizes. The incline gear remains at the middle
position during CD playback.
SLED POSITION
The
sled motor moves the laser assembly away from home position at the spindle
motor. The laser assembly‘s home position is marked as it blocks the light to a
photo detector sensor. This picture shows the photo sensor location under the
sled motor shaft.
- FOCUS COILVoltage applied to the focus coil that is connected to the lens opposes a stationary vertical magnet. The force generated moves the objective lens up or down to focus the laser spot on the information layer of the disc.
- LASERA ribbon cable connects the laser assembly to its circuit board. A circuit board connector clamps the assembly’s ribbon cable. Free the cable from the connector by pulling the connector tabs on both sides 1mm toward the cable. The connector will slide out. In a replacement laser assembly, a spot of solder is placed on the foils of the ribbon cable to protect the laser diode from static damage that will shorten its life. Remove the solder spot AFTER connecting the laser assembly cable to the circuit board.
