Table Motor Drive; Front Panel Rotary Encoder Operation; Direction Of Rotation; Tray Table Position Sensors - Sony CDP-CX235 Training Manual

Table Motor Drive

Syscon IC501 drives the Disc's Tray Table. IC501 receives information
from three tray table position sensors and the front panel rotary encoder
knob to determine where the tray is and where to stop.
Front Panel Rotary Encoder
Operation
At the front panel there is a large knob that is used to select discs. The
knob is connected to a rotary encoder switch on the jog board behind the
knob. When the knob is turned to the next detent position, the display
shows the information on the next disc in the tray. If that disc is desired,
the same encoder button is pressed ("Enter") and that disc is accessed.
When the disc door is open, the rotary encoder rotates the tray to any disc
slot position, permitting the user to load discs. The FL display tube dis-
plays the same disc slot number marked on the tray at the opened door.
With the door closed, the display tube shows the disc slot facing the CD
Mechanism.
Display
Front
Panel
The rotary encoder switch is connected to Syscon at
IC501/pins 42 and 43 respectively. At the encoder
itself there are three contacts for the rotary encoder
and two for the enter button. In the detent position,
pin 1 is connected to pin 2 (ground). In the neutral
position (in-between detents), pin 3 is connected to
pin 2.
Rotary
Encoder
knob
Door
Rotary
Encoder
rear view
3 2
19

Direction of Rotation

The encoder is constructed so its direction from the detent position can
be determined by IC501. In the detent position, pin 1 is grounded. In the
neutral position, pin 3 is grounded. When turning the encoder knob in the
CCW direction, both pins 1 and 3 are momentarily grounded before pin 1
is ungrounded ("make before break") in neutral. When turning the en-
coder knob CW, both pins 1 and 3 are open circuited before pin 3 is
grounded in neutral. This is how IC501 determines the direction the user
has turned the knob and rotates the tray accordingly.

Tray Table Position Sensors

Three sensors monitor the gaps in the tray table's rings to determine home
position. Sensors IC802 and IC803 are used to determine the center of
each disc slot. Sensors IC801 and the composite signal from IC802 and
IC803 are used to determine where the tray is positioned.
For testing purposes, when the tray table is in a detent position, sensors
IC802 and IC803 should output a HIGH at CN506/pins 1 and 2. Sensor
IC801 outputs a HIGH when certain disc slot positions have been se-
lected. The chart lists the disc positions IC801 will output a high in the
current 200 disc changers.
With the door open, you can rotate rotary encoder and verify the disc
positions in case the chassis has been bent or incorrectly aligned.
Disc positions when IC801 Output = HIGH (CN506/4)
Disc Positions
(# displayed on the tray)
10-18
1
30-39
50-60
70-71
90-92
110-113
130-134
150-155
170-176
190-197
Number of disc slots
8
9
10
1
2
3
4
5
6
7