FILTER BLOCK
Since the sound signal from the CPU is a stepped waveform, the filter block is added to smooth the waveform.
Amp.
IC301
Filter Block
Q305
CPU LSI1
POWER AMPLIFIER (IC301: LA4598)
The power amplifier is a
Pin No. | Terminal | In/Out | Function |
1 | Power GND | In | Ground (0V) source |
2 | Ch1 B.S. | — | Terminal for a bootstrap capacitor |
3 | Ch1 OUT | Out | Channel 1 output |
4 | VCC | In | +9V source |
5 | Ch1 N.F. | In | Negative feedback input |
6 | Ch1 IN | In | Channel 1 input |
7 | D.C. | — | Terminal for a decoupling capacitor |
8 | Pre GND | In | Ground (0V) source |
9 | Stand by | In | Power control signal input. 0 V: Off, +9 V: On |
10 | Ch2 IN | In | Channel 2 input |
11 | Ch2 N.F. | In | Negative feedback input |
12 | Ch2 OUT | Out | Channel 2 output |
13 | Ch2 B.S. | — | Terminal for a bootstrap capacitor |
14 | NC | — | Not used |
LED DRIVING
La ~ Lg | LED |
| |
| Latch | MD0 ~ MD3 | |
| IC3 |
| |
| (Segment) | MWEB | |
| LED | MD4 ~ MD7 | |
| Latch | ||
| MA0 | ||
Q2 ~ Q4 | IC2 | ||
|
(Common)
CPU
LSI1
Keyboard LEDs
LVDD
LX0 ~ LX7
Q5 ~ Q8
LY1 ~ LY7 
Q1 ~ Q4
LG
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