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CX-692
3) 0.6mm UP/DOWN Operation
In order to secure clearance with the neighboring disc
the stage mechanism is driven down by the ELV motor
(M4) when clamping is complete. The microcomputer
detects the completion of clamping, and when the tray
Motor is brought to a full stop, the ELV motor (M4) is
forcibly driven for a 400 ms interval in the downward
direction.
When the tray is being retracted, the ELV motor (M4) is
controlled to match the value of EPVO calculated during
the elevation operation. The tray retraction operation is
started when the tray has been moved to the prescribed
position.
4) Disc Detection
The DSP signal waveform (voltage) at the DSP switch
(S851) is used for determinating the existence and non-
existence of a disc and the disc type (8cm or 12cm). The
disc detection operations are carried out while the Tray
is being pulled out of the magazine. Disc detection is
determined when the light passes through (DISC
waveform L:less than 1.5V) or is interrupted (DISC
waveform H:1.5V or above) with an array of LEDs and
photo transistors above and below the Tray.
Each motor is driven by the driver IC305 (LB1836M).
LB1836M is an IC which usually operated through the
combination of H and L of the 4 lines l1, l2, l3 and l4.
With this system, l1=l3 and control is realized through a
combination of H and L of the 3 lines l1, l2 and l4.
Making continuous detection of the DISC waveforms during
the periods "A" and "B" shown above, when "L" is detected
even once, the period is deemed "L" and when "L" is not
detected at all, the period is deemed "H" to make the
determination according to the table indicated at right.
When the magazine is inserted and disc detection is started,
if when period "A" is deemed "H", the determination is that
the disc is found (12cm) and the disc will be restored before
proceeding to the next disc detection.
[
[
]
]
OFF
ON
DSP switch
DISC(12cm)
DISC(8cm)
DISC(Tray only)
A
B
40msec
ELV Motor Tray Motor l1,l3 l2 l4
Forward Brake H H L
Reverse Stand-by L L H
Brake Forward H L H
Stand-by Reverse L H L
Brake Brake H H H
Stand-by Stand-by L L L
* ELV Motor Forward : ELV-up (Disc No. Down)
Tray Motor Forward : Tray Ejection
Fig. 20
A
B
12cm
H
H
8cm tary
L
H
Nil.
-
L
8cm adapter
H/L
H
Determination
H:Found
H:Found
L:Not found
L:Not found
/8cm