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Audio / Display Output
Analog Audio Output
The left and right channels of Servo Control IC101 are applied to amplifier
IC401. Their outputs are AC coupled to the rear panel phono jacks. The
following signal levels were measured using the Sony YEDS-18 test disc
track #5 (10kHz mono, 0db).
IC401 voltages
Measurement Pin 2 Pin 3 Pin 1
DC 0V 0V 0V
AC 3Vp-p 3Vp-p 5Vp-p
Muting transistors Q325, Q327, and Q425 mute the output audio at power
ON and OFF.
Digital Output
The digital output signal from Servo Control IC101/pin 60 is applied to
IC901 at the rear panel of the changer. Inside IC901 is a visible LED in a
plastic package that can connect to the consumer standard optical cable.
There is always a base waveform at the Digital Output pin 60 of IC101,
producing an average DC voltage of 2.47Vdc. This waveform keeps the
optical output LED lit (red) when the changer is powered ON.
1
T
Digital Output Signal Power ON, No PB
Name Location Frequency
Digital Output
(electrical)
CN502/pin 10 (from
IC101/pin 60)
1.4MHz
Time base = 0.5usec/div
When a disc is played, the base frequency square wave is replaced with
data.
1
T
Digital Output Signal Power ON, Disc PB
Name Location Frequency
Digital Output
(electrical)
CN502/pin 10 (from
IC101/pin 60)
data
Time base = 0.5usec/div
Display
SQ data and clock from Servo Control IC101/pins 1 and 2 are applied to
Syscon IC501 for processing. The results of this data will be the CD time,
track, and name information applied to the FL display driver IC701. The
SQ data and clock are only present when a disc is played.
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