Safety Interlock; Ac Power Source - C.E.C. 780CD Service Manual

SAFETY INTERLOCK
The Digital Compact Disc Player reads the disc signal by
detecting the laser beam. It must be avoided for the human
body to directly receive the beam. Especially human eyes are
badly affected by the beam. Therefore, the unit is equipped
with an interlock to prevent the unnecessary laser outputs.
The laser outputs are controlled by the injection or cutoff of
the constant voltage source to the laser diode with Pin 43 of
ICO6 (LC6554H-4301). When Pin 43 is in "L" (Low) level, the
laser emits the beam. When Pin 43 is in "H" (High) level, the
laser does not emit the beam.
Pin 43 is set in "H" level when the unit is loaded with the
disc and it reads the index signals or when the unit is set in
the play mode after that. When the unit reads the index
ICO6
LC6554H-4301
Pick-up Inner Limit
SWITCH
PLAY
SWITCH
signals and the following two conditions are met, the laser
emits the beam.
1) When the Pick-up Inner Limit Switch is on. (The disc tray
is closed.)
2) The pickup is located at the area of the minimum internal
circumference.
After the above conditions are met and the index signals
_have been read, the laser emits the beam when the following
two conditions are met.
1) When the PLAY button is pressed.
2) When the PLAY indicator is on.
CONTROL |
AC POWER SOURCE
LASER
DIODE
FL401
PLAY Indicator
qs