Philips AS660C/41 - Page 68

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AF2 BOARD oe
BRIEF INTRODUCTION OF PCBAS AF-2:
The AF2 board consists of the following :
a. SOFAC IC which includes functions such as source selection, loudness control, bass control, treble control, front/rear
volume control and muting function. All function are controllable via 12¢ data from the master microprocessor.
The SOFAC IC caters for 4 input sources, namely tuner, tape, CD and AUX.
b. Karaoke Mic. Mixing. (not applicable for MC150/MC170)
NK : Non Karaoke
SK : Simple Karaoke which caters for mic. mixing with additional mic. amp. board.
FK : Full Karaoke with vocal fader and echo effect with additional Karaoke board.
ees Incredible Sound using IC LM324DT quad Op-Amp to create phase shifting and spatial effect.
d. Headphone Amplifier using Op-Amp . NUM4556M.
e. CD standby control circuit which switches on the CD servo supply in CD mode only.
f. Headphone Sensing circuit to mute speaker for Dolby Prologic application.
f.
Attenuation
network
is
provided
at
the
output
of
the
AF2
board
for
interfacing
with
power
board
of
different
output
:
power.
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PCS 83 420