BBK AV210, Service Manual

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1.2.1  Hi-Fi Processing Mode: The signal flow is the same as that of the standard stereo 
mode. The electronic volume adjusting IC N402 shut off other audio channels under the 
control of the CPU. Neither the sound fields processing and balance adjustment can be 
performed. Therefore, S-SW cannot be sent out and the whole unit is in the two channel 
output mode.

1.2.3  Cyber Logic: L&R channel signals sent out from N407A and N407B reach the IC 
N402 where the electronic master volume is adjusted. Meanwhile, the signals selected 
from the channel L passes through the low pass filter N408A where it is divided into two 
lines. One line reaches the pin 13 of N411 through R657 and another line reaches the 
pin 5 of N411 after it is amplified through the low pass filter N406B. The signal selected 
from the channel R reaches the pin 1 of N411 after being amplified through the low pass 
filter N408B. N411's pin 9 (SEL) is the low level. According to the real value table, the 
S-SW signal sent out from the pin 4 is added to the pin 6 of N402 where the electronic 
volume is adjusted. The pins 10&11 (SWLL) are high level. According to the real value 
table, the central channel signal (S-C) sent out from the pin 14 of N411 and the surround 
channel signal (S-S) sent out from the pin 15 of N411 are added to the pins 12, 2 and 5 
of N410. (The S-S is divided into two signalssurround left and surround right.) At this 
time, the pins 9, 10 and 11 (SEL) are low level. According to the real value table, these 
three lines of signals sent out from the pins 14, 15 and 4 reach the IC N410 where the 
volume is adjusted separately. This unit is in the six-channel output mode.

The relationship of all input source switches and sound processing mode is shown as 
Figure 1.

Press the INPUT 

button to select 

circularly

Three modes 

input

Hi-Fi mode

Only L & R channel outputs, 

Sound fields and 

EQ settings are invalid

Only L,R & SW channel outputs, 

Capable of setting the 

Concert sound field and EQ

6 CH output, capable of setting 
the Theater sound field and EQ 

6 CH output, capable of setting 
the Theater sound field and EQ 

Standard 

Stereo 

mode

Cyber Logic 

mode

5.1 CH input

(Figure 1)

volume control IC M62446